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https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2010.pdf | 1 | AVOGADRO EXAM 2010
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
13 MAY 2010 TIME: 75 MINUTES
This exam is being written by several thousand students. Please be sure that you follow the instructions below.
We'll send you a report on your performance. Top performers are eligible for a prize. The names of the top 200 students
will be published in the September issue of Chem 13 News.
1. Print your name here:
2. Print your school name
and city on your STUDENT
RESPONSE sheet.
3. Select, and enter on the STUDENT RESPONSE sheet, one of the following CODE numbers:
Code 1 Ontario , now studying Grade 11 Chemistry
in a nonsemestered school
Code 2 Ontario , now studying Grade 11 Chemistry
in a semestered school
Code 3 Ontario , Grade 11 Chemistry
already completed
Code 4 Any other Ontario student
Code 5 Manitoba or Saskatchewan high school
student
Code 6 Québec high school student
Code 7 not used
Code 8 Alberta or British Columbia high school
student
Code 9 New Brunswick, Newfoundland, Nova Scotia,
or Prince Edward Island high school student
Code 10 Northwest Territories, Nunavut, or Yukon
high school student
Code 11 High school student outside Canada
Code 12 Teacher
4. Print
your name (last name, first name and optional
middle initial) on the STUDENT RESPONSE sheet .
Also fill in the corresponding circles below your printed
name.
5. Carefully detach the last page. It is the datasheet.
6. Now answer the exam questions. Questions are not in
order of difficulty. Indicate your choice on the STUDENT RESPONSE sheet by marking one letter beside the question number.
• Mark only one answer for each question. • Questions are all of the same value. • There is a penalty (1/4 off) for each incorrect
answer, but no penalty if you do not answer.
7. Take care that you make firm, black pencil marks, just
filling the oval.
Be careful that any erasures are complete—make the
sheet white again.
Carefully detach the last page.
It is the Data Sheet. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2010.pdf | 2 |
2 / AVOGADRO EXAM © 2010 UNIVERSITY OF WATERLOO 1 Compared to an electron, a proton has
A the same charge and about the same mass
B the same charge but a much greater mass
C the opposite charge and much less mass
*D the opposite charge and a much greater mass
E no charge and a much smaller mass
2 Argon has three isotopes with relative atomic masses
of 36.0, 38.0 and 40.0. Given that the relative atomic
mass of naturally occurring argon is 39.95, which of the following statements must be correct?
A
40Ar is less abundant than 38Ar.
*B 40Ar is more abundant than either 36Ar or 38Ar.
C 38Ar is more abundant than 36Ar.
D 36Ar is more abundant than 40Ar.
E Another isotope of lesser mass must exist.
3 An incomplete equation describing the nuclear decay
of boron-9 is given below. How many neutrons or
protons are also produced?
9
5B → 8
4Be + ?
A one neutron
*B one proton
C one neutron and one proton
D two protons
E two neutrons
4 When 50.0 mL of water and 50.0 mL of ethanol are
mixed, the total volume is found to be 96.5 mL. What
is the density of this water-ethanol solution?
A 1.78 g/mL
B 0.895 g/mL
C 0.211 g/mL
D 3.45 mL
*E 0.927 g/mL 5 Which of the following has a linear geometry?
A O
3
B NO 2−
*C C
2H2
D H2S
E F 2O
6 Which of the following elements has properties that
most closely resemble those of calcium, Ca?
A sodium, Na
B potassium, K
*C magnesium, Mg
D bromine, Br
E krypton, Kr
7 What is the formula of lead(II) nitrate?
A Pb
3N2
B Pb 2N3
C Pb 2NO 3
*D Pb(NO 3)2
E PbNO 3
8 Which of the following reacts with moisture in the air
to form acid rain?
*A sulfur trioxide, SO 3
B nitrogen, N
2
C carbon dioxide, CO 2
D methane, CH 4
E ozone, O
3
9 Which of the following is an example of chemical
change?
A boiling water
B dissolving alcohol in water
C heating copper metal
D compressing a gas
*E rusting of iron
AVOGADRO EXAM 2010 - Answers
Densities, in g/mL:
Water, 1.00
Ethanol , 0.789 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2010.pdf | 3 |
© 2010 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 3 10 What is [Na+] in a solution obtained by mixing 50.0 mL
of 0.100 mol/L NaNO 3(aq) and 25.0 mL of
0.100 mol/L Na 2CO 3(aq)?
*A 0.133 mol L−1
B 0.200 mol L−1
C 0.300 mol L
−1
D 0.167 mol L−1
E 0.125 mol L−1
11 What is the mass of 0.67 mol Na?
A 29 mg
*B 15 g
C 10 g
D 23 g
E 0.67 g
12 One litre of oxygen gas is compared to one litre of
carbon dioxide gas, both at 25 oC and 100 kPa.
Which statement is correct?
A The density of the oxygen gas is greater than that
of the carbon dioxide gas.
B On average, the kinetic energy of a carbon
dioxide molecule is greater than that of an oxygen
molecule.
C On average, a carbon dioxide molecule moves
faster than does an oxygen molecule.
D On average, the kinetic energy of carbon dioxide
molecule is less than that of an oxygen molecule.
* E The two samples contain the same number of
molecules.
13 What is the net ionic equation for the reaction of
Na
2CO 3(aq) and CaCl 2(aq)?
A Na+(aq) + Cl−(aq) → NaCl(s)
B Na 2CO 3(aq) + CaCl 2(aq)
→ 2 NaCl(aq) + CaCO 3(s)
C Ca+(aq) + CO 3−(aq) → CaCO 3(s)
*D Ca2+(aq) + CO 32−(aq) → CaCO 3(s)
E 2 Na+(aq) + CO 32−(aq) → CO 2(g) + Na 2O(s) 14 In an experiment, 16.0 g SO 2 is treated with 6.0 g O 2
and 18.0 g SO 3 is obtained. A balanced chemical
equation for the reaction is given below.
2 SO 2(g) + O 2(g) → 2 SO 3(g)
What is the percentage yield of SO 3 in this experiment?
A 25%
B 38%
C 67%
D 60%
*E 75%
15 What amount of C
8H10O2N4 contains the same
number of C atoms as 2 mol CO 2?
A 2 mol
B 8 mol
C 4 mol
*D 0.25 mol
E 0.5 mol
16 In which region of the peri odic table would you find the
elements of highest electronegativity?
A top, left
* B top, right
C near the middle
D bottom, left
E bottom, right
17 Which of the following has an odd-number of
electrons?
A NO 3−
*B NO 2
C N
2O
D NO+
E NO 2− Molar masses
(in g/mol)
SO 2 64.1
O2 32.0
SO 3 96.2
Using the molar masses given, the “correct”
answer is E. However, the molar mass given for
SO 3 is wrong. Question 14 was deleted. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2010.pdf | 4 |
4 / AVOGADRO EXAM © 2010 UNIVERSITY OF WATERLOO 18 What is the correct electron arrangement for a
scandium (Sc) atom? (The first number in each list refers to the number of electrons in the first shell; the
second number refers to the number of electrons in the
second shell; and so on.)
* A 2, 8, 9, 2
B 2, 8, 2, 8, 1
C 2, 8, 8, 3
D 10, 10, 1
E 4, 4, 4, 4, 1
19 A 10.0 L cylinder containing neon gas with a measured
pressure of 550 kPa at 298 K is connected through a
valve to a 2.50 L cylinder containing 275 kPa of helium gas at 298 K. The valve is opened and the gases mix
with no change in temperature. What is the final total
pressure in the system?
A 277 kPa
B 326 kPa
C 413 kPa
* D 495 kPa
E 599 kPa
20 What is the H-N-H angle in the NH
3 molecule?
Choose the closest value.
A 45o
B 90o
*C 109o
D 120o
E 180o
21 Which of the following molecules has the strongest
carbon-carbon bond?
A ethanol, CH
3CH 2OH
B ethanoic acid, CH 3CO 2H
C ethane, C 2H6
D ethene, C 2H4
*E ethyne, C 2H2
22 Consider the Lewis structure below for the CH 3CCH
molecule.
What is the maximum number of atoms that can lie in
the same plane?
A three
B four
*C five
D six
E seven
23 The following ions all have the same number of
electrons.
O
2−, F−, Na+, Mg2+
In which of following lists are these ions arranged in
order of increasing radius (from smallest to largest)?
A O
2− < F− < Na+ < Mg2+
* B Mg2+ < Na+ < F− < O2−
C Na+ < Mg2+ < O2− < F−
D Mg2+ < Na+ < O2− < F−
E F− < O2− < Na+ < Mg2+
24 Which of the following is not a Bronsted-Lowry
conjugate acid-base pair?
A NH
3 and NH 2−
B OH− and O2−
*C H 3O+ and OH−
D HCl and Cl−
E NH 4+ and NH 3
CC C HH
HH |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2010.pdf | 5 |
© 2010 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 5 25 A 0.350 g sample of acid HX requires 25.4 mL of
0.140 mol/L NaOH(aq) for complete reaction. What is the molar mass of the acid?
A 42.3 g/mol
B 68.4 g/mol
* C 98.4 g/mol
D 121 g/mol
E 84.6 g/mol
26 What is the density of carbon dioxide gas at 0.00
oC
and 101.3 kPa?
* A 1.96 g/L
B 0.0446 g/L
C 22.4 g/L
D 44.6 g/L
E 0.509 g/L
27 An element M forms an ion M
3+. The atom M and the
ion M3+ have the same
* A number of protons
B number of electrons
C radius
D ionization energy
E chemical properties
28 Methanoic acid, HCOOH, is a weak electrolyte. In a
solution prepared by dissolving 0.10 mol HCOOH in water to make 1.0 L of solution, approximately 4.1% of
the HCOOH molecules ionize. What is the pH of this
solution?
A 0.61
B 1.39
* C 2.39
D 4.10
E 6.10
29 In March of this year, the International Union of Pure
and Applied Chemistry (IUPAC) officially approved the name and atomic symbol (Cn) for element 112.
What is the official name of element 112?
*A copernicium
B californium
C cupenium
D cernium
E cuternium
30 Element 114 would be placed directly below lead
(element 82). At the present time, nuclear
scientists have managed to synthesize only a few atoms of element 114 at any one time and thus,
the physical appearance of a larger sample is not
yet known. Based on its position in the periodic table, element 114 is most likely to be a
A reddish-brown volatile liquid
B a pale yellow green gas
C a colourless crystal
* D a gray-silvery metal
E a black powdery solid
31 Sodium hydroxide, NaOH, is most likely found in
which household product?
A vinegar
B soap
C bleach
D window cleaner
* E drain cleaner
|
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2010.pdf | 6 |
6 / AVOGADRO EXAM © 2010 UNIVERSITY OF WATERLOO 32 A balloon was filled with helium gas to a volume of
3.0 L on a day when the atmospheric pressure was 101 kPa and the temperature was 31
oC. The
following day, the atmospheric pressure and temperature were measured as 98.3 kPa and 33
oC,
respectively. The volume of the balloon had not changed. Which of the following statements is consistent with these data?
A Based on the changes in pressure and
temperature that occurred, the volume of the
balloon would not be expected to change.
B The balloon absorbed some air from the
atmosphere.
* C Some helium gas leaked out of the balloon.
D Helium atoms in the balloon lost energy to the
surroundings.
E Based on the changes in pressure and
temperature that occurred, the volume of the
balloon should have decreased.
33 To prepare exactly 250 mL of 0.10 mol/L HCl(aq)
starting from 1.0 L of 0. 20 mol/L HCl(aq), one should
A slowly add exactly 125 mL of 0.20 mol/L HCl(aq)
to exactly 125 mL of water.
*B slowly add exactly 125 mL of 0.20 mol/L
HCl(aq) to about 100 mL of water and then
dilute with water to a total volume of 250 mL.
C evaporate 750 mL of water from 1.0 L of 0.20
mol/L HCl(aq).
D slowly add exactly 125 mL of water to exactly
125 mL of 0.20 mol/L HCl(aq).
E add 750 mL of 0.10 mol/L NaOH to 1.0 L of
0.20 mol/L HCl(aq).
34 Which of the following dilute solutions would allow a
chemist to distinguish between dilute solutions of
NaCl(aq) and NaNO 3(aq)?
A NaOH(aq)
B HCl(aq)
C NH 3(aq)
D H 2SO 4(aq)
*E AgNO 3(aq) 35 Compared to a chlorine atom, a sodium atom has a
larger
* A radius
B mass
C number of electrons
D ionization energy
E electronegativity
36 Which of the following bonds has the greatest ionic
character?
A C−H
B O−H
C O−F
* D H−F
E C−O
37 A compound is found to be 85.62% carbon by mass
and 14.38% hydrogen. What is the simplest formula
of this compound?
A CH
* B CH
2
C CH 3
D CH 4
E C3H4
38 Mercury(II) sulfide, HgS, is practically insoluble in pure
water. Its solubility at 25 oC is probably no more than
3×10−25 g/L. Of the following quantities of pure water,
which is the smallest quantity that could be used to
make a saturated solution of HgS?
A 20,000 L
B 1000 L
C 10,000 L
* D 2000 L
E 200 L
Molar masses
(in g/mol)
Hg 200.6
S 32.07 For question 33, the intended answer was
“B”, but the volume of water was mistakenly given as 200 mL when 100 mL is what was
intended. Question 33 was deleted. Answer
“A” is not the correct answer because 125 mL of HCl(aq) and 125 mL of water may not
give exactly 250 mL of solution because
volumes are not exactly additive. See
question 4 for an extreme example. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2010.pdf | 7 |
© 2010 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 7 39 What is the pH of a solution prepared by mixing
50.0 mL of 0.010 mol/L HCl(aq) and 50.0 mL of
0.010 mol/L Ca(OH) 2(aq)? Assume the temperature
is 25 oC.
A 2.00
B 2.30
C 7.00
*D 11.70
E 12.00
40 Consider the Lewis structure below. What is the
charge on this molecule or ion?
A −2
* B −1
C 0
D +1
E +2
FB r FKw = 1.0×10−14 at 25 oC |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2010.pdf | 8 |
8 / AVOGADRO EXAM © 2010 UNIVERSITY OF WATERLOO
DATA SHEET
AVOGADRO EXAM 2010
DETACH CAREFULLY
C o n s t a n t s : C o n v e r s i o n f a c t o r s :
NA = 6.022 1023 mol1 1 atm = 101.325 kPa = 760 torr = 760 mm Hg
R = 0.082058 atm L K1 mol1 0oC = 273.15 K
= 8.3145 kPa L K1 mol1
= 8.3145 J K1 mol1
Kw = 1.0×10−14 (at 298 K)
F = 96 485 C mol−1
Equations: PV = nRT k t1/2 = 0.693 pH = pK a + log ( [base] / [acid] ) 24
2bb a cx
a
1
1A
18
8A
1
H
1.008
2
2A
13
3A
14
4A
15
5A
16
6A
17
7A 2
He
4.003
3
Li
6.941 4
Be
9.012 5
B
10.816
C
12.01 7
N
14.01 8
O
16.009
F
19.0010
Ne
20.18
11
Na
22.99 12
Mg
24.31
3
3B
4
4B
5
5B
6
6B
7
7B
8
9
8B
10
11
1B
12
2B 13
Al
26.9814
Si
28.09 15
P
30.97 16
S
32.0717
Cl
35.4518
Ar
39.95
19
K
39.10 20
Ca
40.08 21
Sc
44.96 22
Ti
47.88 23
V
50.94 24
Cr
52.00 25
Mn
54.9426
Fe
55.8527
Co
58.9328
Ni
58.6929
Cu
63.5530
Zn
65.3831
Ga
69.7232
Ge
72.59 33
As
74.92 34
Se
78.9635
Br
79.9036
Kr
83.80
37
Rb
85.47 38
Sr
87.62 39
Y
88.91 40
Zr
91.22 41
Nb
92.91 42
Mo
95.94 43
Tc
(98) 44
Ru
101.145
Rh
102.946
Pd
106.447
Ag
107.948
Cd
112.449
In
114.850
Sn
118.7 51
Sb
121.8 52
Te
127.653
I
126.954
Xe
131.3
55
Cs
132.9 56
Ba
137.3 57-71
La-Lu 72
Hf
178.5 73
Ta
180.9 74
W
183.9 75
Re
186.276
Os
190.277
Ir
192.278
Pt
195.179
Au
197.080
Hg
200.681
Tl
204.482
Pb
207.2 83
Bi
209.0 84
Po
(209) 85
At
(210) 86
Rn
(222)
87
Fr
(223) 88
Ra
226 89-103
Ac-Lr 104
Rf 105
Db 106
Sg 107
Bh 108
Hs 109
Mt 110
Ds 111
Sg 112
Cn
57
La
138.9 58
Ce
140.1 59
Pr
140.9 60
Nd
144.2 61
Pm
(145) 62
Sm
150.463
Eu
152.0064
Gd
157.365
Tb
158.966
Dy
162.567
Ho
164.968
Er
167.3 69
Tm
168.9 70
Yb
173.071
Lu
175.0
89
Ac
227. 90
Th
232.0 91
Pa
231.0 92
U
238.0 93
Np
237.094
Pu
(244) 95
Am
(243) 96
Cm
(247) 97
Bk
(247) 98
Cf
(251) 99
Es
(252) 100
Fm
(257) 101
Md
(258) 102
No
(259) 103
Lr
(260) |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2009.pdf | 1 | AVOGADRO EXAM 2009
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
21 MAY 2009 TIME: 75 MINUTES
This exam is being written by several thousand students. Please be sure that you follow the instructions below.
We'll send you a report on your performance. Top performers are eligible for a prize. The names of the top 200 students
will be published in the September issue of Chem 13 News.
1. Print your name here:
2. Print your school name
and city on your STUDENT
RESPONSE sheet.
3. Select, and enter on the STUDENT RESPONSE sheet, one of the following CODE numbers:
Code 1 Ontario , now studying Grade 11 Chemistry
in a nonsemestered school
Code 2 Ontario , now studying Grade 11 Chemistry
in a semestered school
Code 3 Ontario , Grade 11 Chemistry
already completed
Code 4 Any other Ontario student
Code 5 Manitoba or Saskatchewan high school
student
Code 6 Québec high school student
Code 7 not used
Code 8 Alberta or British Columbia high school
student
Code 9 New Brunswick, Newfoundland, Nova Scotia,
or Prince Edward Island high school student
Code 10 Northwest Territories, Nunavut, or Yukon
high school student
Code 11 High school student outside Canada
Code 12 Teacher
4. Print
your name (last name, first name and optional
middle initial) on the STUDENT RESPONSE sheet .
Also fill in the corresponding circles below your printed
name.
5. Carefully detach the last page. It is the datasheet.
6. Now answer the exam questions. Questions are not in
order of difficulty. Indicate your choice on the STUDENT RESPONSE sheet by marking one letter beside the question number.
• Mark only one answer for each question. • Questions are all of the same value. • There is a penalty (1/4 off) for each incorrect
answer, but no penalty if you do not answer.
7. Take care that you make firm, black pencil marks, just
filling the oval.
Be careful that any erasures are complete—make the
sheet white again.
Carefully detach the last page.
It is the Data Sheet. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2009.pdf | 2 |
2 / AVOGADRO EXAM © 2009 UNIVERSITY OF WATERLOO 1 The “lead” of a pencil is mostly
A lead, Pb
*B carbon, C
C silicon dioxide, SiO 2
D silicon, Si
E calcium carbonate, CaCO 3
2 How many protons, neutrons and electrons are there in
a single atom of
209
84Po?
A 84 protons, 84 neutrons, 209 electrons
B 84 protons, 209 neutrons, 84 electrons
C 209 protons, 125 neutrons, 209 electrons
D 125 protons, 84 neutrons, 125 electrons
*E 84 protons, 125 neutrons, 84 electrons
3 The mass of one atom of 12C is exactly 12 atomic mass
units. With the assumption that a proton and a neutron are equally massive, what is the total number of protons
and neutrons in the body of a 75-kg person? (You may
neglect the mass of an electron is negligible compared to that of a proton or neutron.)
A 2.2 × 1027
*B 4.5 × 1028
C 8.0 × 1021
D 3.8 × 1023
E 8.0 × 1024
4 Mercury, Hg( l), has a density of 13.6 g mL−1 at 25 °C.
What is the volume of 4.25 grams of Hg( l) at 25 oC?
A 0.0173 mL
B 3.20 mL
C 0.0562 mL
*D 0.313 mL
E 0.0735 mL 5 Which of the following molecules has the same number
of electrons as a water molecule?
*A HF
B BH 3
C CO
D H2S
E F 2
6 Which of the following elements is a liquid at room
temperature and atmospheric pressure?
A chlorine
B phosphorus
C sulfur
*D bromine
E iodine
7 What is the formula of the binary compound formed
between Mg and P?
A MgP
B Mg 2P
C MgP 2
D Mg 2P3
*E Mg 3P2
8 Which of the following elements has no known stable
compounds?
*A neon, Ne
B xenon, Xe
C gold, Au
D platinum, Pt
E uranium, U
9 Which of the following elements is believed to be the
most abundant in the earth’s crust?
A hydrogen
*B oxygen
C carbon
D nitrogen
E silicon AVOGADRO EXAM 2009 - Answers |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2009.pdf | 3 |
© 2009 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 3 10 Which of the following has the highest concentration at
equilibrium when one mole of HCl is dissolved in 1.0 L of water at 25
oC?
*A Cl−
B Cl+
C Cl 2
D H 2
E HCl
11 What is the symbol for the atom or ion that results from
the addition of two protons to a single atom of 42
20Ca ?
A 42 2+
22Ca
B 44 2+
22Ca
C 42
22Ti
*D 44 2+
22Ti
E 44 2+
20Ti
12 In a mixture of N 2 and O 2 gases, all the N 2 molecules
and the O 2 molecules have the same
A average speed
* B average kinetic energy
C partial pressure
D average molecular mass
E average momentum
13 When ethanol, CH 3CH 2OH, is burned in excess oxygen,
carbon dioxide and water are the only products. What
is the coefficient of O 2 when the chemical equation
representing the combustion reaction is balanced using
the smallest whole number coefficients ?
A 1
B 2
*C 3
D
7
E none of the above 14 In an experiment, 16 g of methane and 32 g of oxygen
react to produce 11 g of carbon dioxide. A balanced chemical equation for the reaction is given below.
CH
4(g) + 2 O 2(g) → CO 2(g) + 2 H 2O(g)
What is the percentage yield of carbon dioxide in this
experiment?
A 10%
B 25%
*C 50%
D 67%
E 75%
15 If an oxide of nitrogen contains 25.9% by mass of
nitrogen, what is its empirical formula?
A NO
B N 2O
C
NO 2
D N 2O4
*E N 2O5
16 What is the percentage by mass of sodium in a mixture
containing 1.00 mol NaCl and 1.00 mol NaF?
A 39.3%
* B 45.8%
C 47.1%
D 50.0%
E 54.8%
17 When the hydrides of the group 16 elements are
arranged in order of increasing boiling point, the order is
*
A H 2S H 2Se H 2Te H 2O
B H 2O H 2S H 2Se H 2Te
C H2Te H 2Se H 2S H 2O
D H 2O H 2Te H 2Se H 2S
E H 2S H 2O H 2Se H 2Te |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2009.pdf | 4 |
4 / AVOGADRO EXAM © 2009 UNIVERSITY OF WATERLOO 18 How many unpaired electrons are there in a ground
state Mn2+ ion?
A zero
B one
C two
D three
* E more than three
19 What is the pressure (in mmHg) of the gas inside the
apparatus below if P atm = 750 mmHg, Δh1 = 40 mm
and Δh2 = 30 mm?
A 710 mmHg
* B 790 mmHg
C 720 mmHg
D 780 mmHg
E 820 mmHg
20
What is the HCH bond angle in a formaldehyde (H 2CO)
molecule? Choose the closest value.
A 45o
B 90o
C 109o
*D 120o
E 180o
21 Which of the following diatomic molecules has the
strongest bond?
*A N 2
B O 2
C F 2
D
Cl 2
E
Br 2 22 Which of the following molecules or ions is planar? (The
central atom is underlined and all other atoms are bonded to it.)
A NH3
B NH4+
C SF4
D SO32−
*E SO3
23 What is the formula of iron(II) sulfate?
A Fe 2S
B FeS 2
*C FeSO 4
D FeSO 3
E
Fe 2(SO 4)3
24
The pH of lemon juice is about 2.3. What is [H+] in
lemon juice?
A 0.36 mol L−1
B 0.83 mol L−1
C 0.10 mol L-1
*D 5.0×10−3 mol L−1
E 0.071 mol L−1
25 Solid aluminum dissolves in hydrochloric acid solution
according to the following chemical equation.
2 Al( s) + 6 HCl( aq) → 2 AlCl 3(aq) + 3 H 2(g)
A reaction mixture contains 0.500 mol HCl and
0.400 mol Al. Assuming the reaction goes to completion, how many moles of the excess reactant remain?
A 0.000 mol
B 0.100 mol
C 0.167 mol
* D 0.233 mol
E 0.400 mol Patm
Δh1
mercury (Hg) Δh2 Gas |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2009.pdf | 5 |
© 2009 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 5 26 What volume does 11 kg of carbon dioxide occupy
at 0 oC and 101.3 kPa?
A 246 m3
*
B 5.6 × 103 L
C 11 L
D 0.25 L
E 0.22 m3
27 What is the ground state electron configuration of an
isolated sulfur (S) atom?
A 1s2 2s2 2p2 3s2 3p2 4s2 3d2 4p2
B 1s2 2s2 2p6 3s1 3p3 3d5
*C 1s2 2s2 2p6 3s2 3p4
D 1s2 2s2 2p6 3s2 3p6
E
1s2 2s2 2p6 3s2 3d6
28 What volume of 0.123 mol/L aqueous H 2SO 4 is needed
to neutralize 40.0 mL of 0.175 mol/L aqueous NaOH? A balanced chemical equation for the reaction is given
below.
H
2SO 4(aq) + 2 NaOH( aq) → Na 2SO 4(aq) + 2 H 2O(l)
*A 28.5 mL
B 56.9 mL
C 114 mL
D 80.0 mL
E 40.0 mL
29 Three successive elements, in order of increasing
atomic number, have these first ionization energies:
1680 2080 494 kJ/mol
Which of following sets represents the three elements?
A N O F
B O F N
C Ne Na Mg
*D F Ne Na
E Na Mg Al 30 Which of the following gases does not burn, does
not support combustion, and has no effect on lime water, Ca(OH)
2(aq)?
A hydrogen, H 2
B oxygen, O 2
C carbon monoxide, CO
* D nitrogen, N 2
E carbon dioxide, CO 2
31 Which of the following elements would you expect to be
the most similar in chemical properties to element 20?
A element 19
B element 21
C element 18
D element 4
*
E element 38
32 A weather balloon filled with helium gas, He( g), has a
volume of 2.00 ×103 m3 at ground level where the
atmospheric pressure is 1.000 atm and the temperature is 27
oC. After the balloon rises high above the earth to
a point where the atmospheric pressure is 0.400 atm, its volume increases to 4.00
×103 m3. What is the
temperature of the atmosphere at this altitude?
*A −33 oC
B −22 oC
C −73 oC
D 22 oC
E 240 oC
33 In which of these compounds is the oxidation state of O
the highest (i.e., the most positive)?
*
A F2O
B O2
C O3
D H 2O2
E H 2SO 4 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2009.pdf | 6 |
6 / AVOGADRO EXAM © 2009 UNIVERSITY OF WATERLOO 34 The molar volumes of C 2H6(g) and H 2(g), measured at
300 K and 10.0 atm, are 2.30 L and 2.51 L, respectively. Which of the following statements accounts for the
observation that the molar volume of C
2H6(g) is smaller
than that of H 2(g)?
A C 2H6 molecules are larger than H 2 molecules.
B The intermolecular attractions in C 2H6(g) are
weaker than they are in H 2(g).
*C The intermolecular attractions in C 2H6(g) are
stronger than they are in H 2(g).
D The average kinetic energy of H 2 molecules is
greater than that of C 2H6 molecules.
E The average kinetic energy of H 2 molecules is less
than that of C 2H6 molecules.
35 When aqueous sodium carbonate, Na 2CO 3, is treated
with dilute hydrochloric acid, HCl, the products are sodium chloride, water and carbon dioxide gas. What
is the
net ionic equation for this reaction?
A Na 2CO 3(aq) + 2 HCl( aq)
→ 2 NaCl( aq) + CO 2(g) + H 2O(l)
B CO 32−(aq) + 2 HCl( aq)
→ H2O(l) + CO 2(g) + 2 Cl−(aq)
*C CO 32−(aq) + 2 H+(aq) → H 2O(l) + CO 2(g)
D Na 2CO 3(s) + 2 H+(aq)
→ 2 Na+(aq) + CO 2(g) + H 2O(l)
E H+(aq) + OH−(aq) → H2O(l)
36 Which of the following is the best Lewis structure (i.e.,
the best electron dot structure) for the N 2O molecule?
A
B
C
*
D
E
37 A 2.4917-g sample of a hydrate of cobalt (II)
fluoride, ⋅x2 2CoF H O , was heated to drive off all of the
water of hydration. The remaining solid weighed
1.4290 g. What is the formula of the hydrate?
A ⋅2 2CoF H O
B ⋅2 2CoF 2H O
C ⋅2 2CoF 3H O
* D ⋅2 2CoF 4H O
E ⋅2 2CoF 5H O
38 How many isomers are there for C 4H8? Consider both
structural (i.e. constitutional) isomers and
stereoisomers.
A one
B two
C three
D four
* E more than four
39 Which of the following combinations reagents react to
form an insoluble precipitate?
A HNO 3(aq) and Ca(OH) 2(aq)
B Zn( s) and HCl( aq)
C Zn( s) and Cu(NO 3)2(aq)
D NaHCO 3(aq) and NaOH( aq)
*E Na 2CO 3(aq) and CaCl 2(aq)
40 Which of the following will occur if a 0.10 mol L−1
solution of acetic acid (CH 3COOH) is diluted to
0.010 mol L−1 at constant temperature?
A the pH will decrease
B the dissociation constant of CH 3COOH will increase
C the dissociation constant of CH 3COOH will decrease
D the hydrogen ion concentration will decrease to
0.010 mol L−1
*
E the percentage ionization of CH 3COOH will increase NN O
NN O
NN O
NN O
NNO |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2009.pdf | 7 |
© 2009 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 7
1
1A
18
8A
1
H
1.008
2
2A
13
3A
14
4A
15
5A
16
6A
17
7A 2
He
4.003
3
Li
6.941 4
Be
9.012 5
B
10.816
C
12.01 7
N
14.01 8
O
16.009
F
19.0010
Ne
20.18
11
Na
22.99 12
Mg
24.31
3
3B
4
4B
5
5B
6
6B
7
7B
8
←
9
8B
10
→
11
1B
12
2B 13
Al
26.9814
Si
28.09 15
P
30.97 16
S
32.0717
Cl
35.4518
Ar
39.95
19
K
39.10 20
Ca
40.08 21
Sc
44.96 22
Ti
47.88 23
V
50.94 24
Cr
52.00 25
Mn
54.9426
Fe
55.8527
Co
58.9328
Ni
58.6929
Cu
63.5530
Zn
65.3831
Ga
69.7232
Ge
72.59 33
As
74.92 34
Se
78.9635
Br
79.9036
Kr
83.80
37
Rb
85.47 38
Sr
87.62 39
Y
88.91 40
Zr
91.22 41
Nb
92.91 42
Mo
95.94 43
Tc
(98) 44
Ru
101.145
Rh
102.946
Pd
106.447
Ag
107.948
Cd
112.449
In
114.850
Sn
118.7 51
Sb
121.8 52
Te
127.653
I
126.954
Xe
131.3
55
Cs
132.9 56
Ba
137.3 57
La
138.9 72
Hf
178.5 73
Ta
180.9 74
W
183.9 75
Re
186.276
Os
190.277
Ir
192.278
Pt
195.179
Au
197.080
Hg
200.681
Tl
204.482
Pb
207.2 83
Bi
209.0 84
Po
(209) 85
At
(210) 86
Rn
(222)
87
Fr
(223) 88
Ra
226 89
Ac
227.0 104
Rf 105
Db 106
Sg 107
Bh 108
Hs 109
Mt 110
Uun 111
Uuu 112
Uub 113
Uut
58
Ce
140.1 59
Pr
140.9 60
Nd
144.2 61
Pm
(145) 62
Sm
150.463
Eu
152.0064
Gd
157.365
Tb
158.966
Dy
162.567
Ho
164.968
Er
167.3 69
Tm
168.9 70
Yb
173.071
Lu
175.0
90
Th
232.0 91
Pa
231.0 92
U
238.0 93
Np
237.094
Pu
(244) 95
Am
(243) 96
Cm
(247) 97
Bk
(247) 98
Cf
(251) 99
Es
(252) 100
Fm
(257) 101
Md
(258) 102
No
(259) 103
Lr
(260) DATA SHEET
AVOGADRO EXAM 2009
DETACH CAREFULLY
C o n s t a n t s : C o n v e r s i o n f a c t o r s :
NA = 6.022 × 1023 mol−1 1 atm = 101.325 kPa = 760 torr = 760 mm Hg
R = 0.082058 atm L K−1 mol−1 0oC = 273.15 K
= 8.3145 kPa L K−1 mol−1
= 8.3145 J K−1 mol−1
Kw = 1.0×10−14 (at 298 K)
F = 96 485 C mol−1
Equations: PV = nRT k t1/2 = 0.693 pH = pK a + log ( [base] / [acid] ) −± −=24
2bb a cx
a |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2008.pdf | 1 | AVOGADRO EXAM 2008
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
15 MAY 2008 TIME: 75 MINUTES
This exam is being written by several thousand students. Please be sure that you follow the instructions below.
We'll send you a report on your performance. Top performers are eligible for a prize. The names of the top 200 students
will be published in the September issue of Chem 13 News.
1. Print your name here:
2. Print your school name
and city on your STUDENT
RESPONSE sheet.
3. Select, and enter on the STUDENT RESPONSE sheet, one of the following CODE numbers:
Code 1 Ontario , now studying Grade 11 Chemistry
in a nonsemestered school
Code 2 Ontario , now studying Grade 11 Chemistry
in a semestered school
Code 3 Ontario , Grade 11 Chemistry
already completed
Code 4 Any other Ontario student
Code 5 Manitoba or Saskatchewan high school
student
Code 6 Québec high school student
Code 7 not used
Code 8 Alberta or British Columbia high school
student
Code 9 New Brunswick, Newfoundland, Nova Scotia,
or Prince Edward Island high school student
Code 10 Northwest Territories, Nunavut, or Yukon
high school student
Code 11 High school student outside Canada
Code 12 Teacher
4. Print
your name (last name, first name and optional
middle initial) on the STUDENT RESPONSE sheet .
Also fill in the corresponding circles below your printed
name.
5. Carefully detach the last page. It is the datasheet.
6. Now answer the exam questions. Questions are not in
order of difficulty. Indicate your choice on the STUDENT RESPONSE sheet by marking one letter beside the question number.
• Mark only one answer for each question. • Questions are all of the same value. • There is a penalty (1/4 off) for each incorrect
answer, but no penalty if you do not answer.
7. Take care that you make firm, black pencil marks, just
filling the oval.
Be careful that any erasures are complete—make the
sheet white again.
Carefully detach the last page.
It is the Data Sheet. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2008.pdf | 2 |
2 / AVOGADRO EXAM © 2008 UNIVERSITY OF WATERLOO 1 Which of the following elements is not a metal?
*A Se
B Sn
C Sr
D Sc
E Cs
2 A colourless, odourless gas is thought to be oxygen.
Which of the following experimental results would support this conclusion?
A Burning the gas in air produces only water.
B The gas extinguishes a flame.
C The gas turns a Ca(OH)
2 solution milky.
*D A glowing piece of wood bursts into flames in the
gas.
E The gas tarnishes silver.
3 Which of the following particles is the most massive?
*A α-particle
B β-particle
C electron
D proton
E neutron
4 What volume of 5.0 mol L
−1 H2SO 4(aq) must be diluted
with water to make 1.00 L of 0.45 mol L−1 H2SO 4(aq)?
*A 0.090 L
B 0.44 L
C 0.090 mL
D 0.045 L
E 2.22 mL
5 How many neutrons are there in the nucleus of
131I?
A 44
B 53
*C 78
D 131
E 184
6 Which group of elements contains no metals or
metalloids?
A group 13
B group 14
C group 15
D group 16
*E group 17
7 Which of these chloride salts is least likely to exist?
A NaCl
B CuCl
C CaCl 2
D FeCl 3
*E MgCl
8 When a sample of atomic hydrogen gas is heated, it
emits violet, blue, green and red light. Which of the
following statements best explains this observation?
*A The energy of the electron in a hydrogen atom is
restricted to certain values.
B The energy of the electron in a hydrogen atom is
not restricted in any way.
C The electron in a hydrogen atom is restricted to one
of only four possible circular orbits.
D The distance between the electron and the nucleus
in a hydrogen atom is restricted to certain values.
E none of the above
AVOGADRO EXAM 2008 - Answers |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2008.pdf | 3 |
© 2008 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 3 9 Which of the following is not a mixture?
A seawater
*B table sugar
C brass
D cement
E smoke
10 Radioactive 131I is used to treat thyroid cancer. An
incomplete chemical equati on for the radioactive decay
of 131I is given below.
131I → ? + −0
1e
What is the missing product in the equation above?
A 130I
B 129I
*C 131Xe
D
131Te
E 131I+
11 Which of the following has the highest concentration in
air at STP?
A He
B H 2O
C CO 2
*D N 2
E O 2
12 The average mass of a solid copper penny is 2.63 g.
What is the mass of one mole of pennies?
* A 1.58×1024 g
B 6.02×1023 g
C 6.36×1023 g
D 63.6 g
E 1.58×1023 g
13 What is the sum of the coefficients when the following
equation is balanced using the smallest whole number coefficients?
__ P
4 + __ Cl 2 → __ PCl 3
A 12
*B 11
C 6
D 5
E 3
14
How many litres of gaseous methane (CH 4) must be
burned in oxygen to produce enough H 2O and CO 2 to
fill a 3.0-L balloon? Assume that H 2O and CO 2 are the
only combustion products and that the temperature and pressure remain constant.
*A 1.0 L
B 1.5 L
C 2.0 L
D 2.5 L
E 3.0 L
15 A compound that contains only Fe and O is 69.9% Fe
by mass. What is the empirical formula of this
compound?
A FeO
B FeO 2
*C Fe 2O3
D Fe 2O
E Fe 3O4
|
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2008.pdf | 4 |
4 / AVOGADRO EXAM © 2008 UNIVERSITY OF WATERLOO 16 If 17.0 grams of sodium chloride are dissolved in water
to make 0.5 L of solution, then what is the final concentration of the solution? Give your answer with
the correct number of significant figures.
*
A 0.6 mol L−1
B 0.58 mol L−1
C 0.581 mol L−1
D 0.3 mol L−1
E 0.291 mol L−1
17 What is the effect of adding a catalyst to a reaction
mixture?
A It increases the equilibrium concentrations of the
products.
B It decreases the enthalpy change of the reaction.
* C It reduces the activation energy of the reaction.
D It increases the value of the equilibrium constant for
the reaction.
E It increases the time it takes for the reaction to
reach equilibrium.
18 How many valence electrons are there in one Al3+ ion?
A 2
B 4
C 6
*
D 8
E 10
19 What volume of He( g) contains the same number of
moles of gas as 1.00 L of N 2(g) at the same
temperature and pressure?
A 7.00 L
* B 1.00 L
C 0.143 L
D 35.7 mL
E 4.00 L 20 What is the HNH bond angle in an ammonia (NH 3)
molecule? Choose the closest value.
A 90o
B 45o
C 120o
*D 109o
E 180o
21 Which of the following types of radiation has the lowest
energy per photon?
*A radio waves
B ultraviolet radiation
C infrared radiation
D
x-rays
E purple laser light
22 An incomplete Lewis structure (i.e. electron dot
structure) for the O 3 molecule is given below.
How many lone pairs of electrons are there in the
completed structure?
A two
B four
C five
*D six
E eight
23 Which of the following is not a common oxide of
nitrogen?
A NO
B NO 2
C N 2O4
D N 2O
*E NO 3
O O O |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2008.pdf | 5 |
© 2008 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 5 24 In an experiment, 0.12 L of 0.10 mol L−1 H2SO 4(aq) and
0.20 L of 0.10 mol L−1 NaOH( aq) are combined. Which
of the following statements is true?
* A The pH of the resulting solution is less than 7.
B The pH of the resulting solution is greater than 7.
C The pH of the resulting solution is close to 7.
D The pH of the resulting solution is exactly 7.
E None of the statements above are true.
25 Solid aluminum dissolves in hydrochloric acid solution
according to the following chemical equation.
2 Al( s) + 6 HCl( aq) → 2 AlCl 3(aq) + 3 H 2(g)
How many moles of H 2 are produced if 17.5 moles of Al
are added to a solution containing 24.8 moles of HCl?
A 26.3 mol
* B 12.4 mol
C 7.30 mol
D 17.5 mol
E 24.8 mol
26 Which of the following choices does not involve a
chemical change?
A evaporation and neutralization
B neutralization and sublimation
C oxidation and sublimation
* D evaporation and sublimation
E neutralization and oxidation
27
Which of the following atoms or ions has the electron
configuration 1s2 2s2 2p6 3s1 in its ground electronic
state?
A Na−
*B Mg+
C K
D Ca+
E
Al3+
28 Which of the following is a brittle solid and an electrical
insulator at room temperature, but an excellent electrical conductor in its liquid form?
A sulphur
* B sodium chloride
C aluminum
D mercury
E carbon
29 Which of the following salts produces a basic solution
when it is dissolved in water?
A KCl
B NH 4Cl
*C K 2CO 3
D NaNO 3
E CuBr 2
30 Which of the following de scribes the pr ocess that
produces Fe( s) from Fe 2O3(s)?
A combustion
B precipitation
C hydrolysis
* D reduction
E oxidation
|
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2008.pdf | 6 |
6 / AVOGADRO EXAM © 2008 UNIVERSITY OF WATERLOO 31 Which one of the following solutions will be the worst
electrical conductor at 25oC?
A 0.10 mol L−1 Na 2SO 4 (aq)
B 0.10 mol L−1 NaCl( aq)
C 0.10 mol L−1 CaSO 4(aq)
* D 0.10 mol L−1 CH 3OH(aq)
E 0.10 mol L−1 CsCl( aq)
32 Which of the following atoms is not present in large
numbers in biological molecules?
A C
* B F
C O
D N
E H
33
In which of these compounds is the oxidation state of Cl
the highest?
A HClO 2
B ClO 2
C Cl2O5
D Cl 2O
* E HClO 4
34 Which of the gases most closely resembles an ideal
gas at standard temperature and pressure?
A CO 2
B NH 3
C HI
*D H 2
E H 2O
35 Which of the following have ground state electron
configurations of the type ns2 np2 ?
A group 2 atoms
B group 4 atoms
C group 6 atoms
*D group 14 atoms
E group 16 atoms
36 Which of the species in the reaction below are
Brønsted-Lowry acids?
−
4HSO + −
3HCO U −2
4SO + H 2CO 3
A −
4HSO and −
3HCO
*
B −
4HSO and H 2CO 3
C −
3HCO and −2
4SO
D −2
4SO and H 2CO 3
*
E −
4HSO and −2
4SO
37 Which of the following is not an alkane?
*
A C 2H4
B C 3H8
C C 4H10
D
C 5H12
E C 6H14
|
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2008.pdf | 7 |
© 2008 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 7 38 What happens when a solution of lithium chloride (LiCl)
and a solution of ammonium nitrate (NH 4NO 3) are
mixed?
A A precipitate forms.
B A new salt is formed.
C A gas is evolved.
D A metal is formed.
* E No reaction occurs.
39 An average person expends approximately 100 kJ to
walk 1 km. How far will the average car travel by the
time it expends the same amount of energy (i.e. 100 kJ)
as a person who walked 1 km? Use the data given below to determine the answer. Choose the closest
answer.
A 2 km
B 0.2 km
* C 0.02 km
D 20 km
E 200 km
40 How many structural isomers are there for C 5H12?
A less than three
* B three
C four
D five
E more than five
Fuel consumption
of an average car, 8 km L−1
Heat of combustion of
gasoline, 50 kJ g−1
Density of gasoline, 0.7 g mL−1 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2008.pdf | 8 |
8 / AVOGADRO EXAM © 2008 UNIVERSITY OF WATERLOO
1
1A
18
8A
1
H
1.008
2
2A
13
3A
14
4A
15
5A
16
6A
17
7A 2
He
4.003
3
Li
6.941 4
Be
9.012 5
B
10.816
C
12.01 7
N
14.01 8
O
16.009
F
19.0010
Ne
20.18
11
Na
22.99 12
Mg
24.31
3
3B
4
4B
5
5B
6
6B
7
7B
8
←
9
8B
10
→
11
1B
12
2B 13
Al
26.9814
Si
28.09 15
P
30.97 16
S
32.0717
Cl
35.4518
Ar
39.95
19
K
39.10 20
Ca
40.08 21
Sc
44.96 22
Ti
47.88 23
V
50.94 24
Cr
52.00 25
Mn
54.9426
Fe
55.8527
Co
58.9328
Ni
58.6929
Cu
63.5530
Zn
65.3831
Ga
69.7232
Ge
72.59 33
As
74.92 34
Se
78.9635
Br
79.9036
Kr
83.80
37
Rb
85.47 38
Sr
87.62 39
Y
88.91 40
Zr
91.22 41
Nb
92.91 42
Mo
95.94 43
Tc
(98) 44
Ru
101.145
Rh
102.946
Pd
106.447
Ag
107.948
Cd
112.449
In
114.850
Sn
118.7 51
Sb
121.8 52
Te
127.653
I
126.954
Xe
131.3
55
Cs
132.9 56
Ba
137.3 57
La
138.9 72
Hf
178.5 73
Ta
180.9 74
W
183.9 75
Re
186.276
Os
190.277
Ir
192.278
Pt
195.179
Au
197.080
Hg
200.681
Tl
204.482
Pb
207.2 83
Bi
209.0 84
Po
(209) 85
At
(210) 86
Rn
(222)
87
Fr
(223) 88
Ra
226 89
Ac
227.0 104
Rf 105
Db 106
Sg 107
Bh 108
Hs 109
Mt 110
Uun 111
Uuu 112
Uub 113
Uut
58
Ce
140.1 59
Pr
140.9 60
Nd
144.2 61
Pm
(145) 62
Sm
150.463
Eu
152.0064
Gd
157.365
Tb
158.966
Dy
162.567
Ho
164.968
Er
167.3 69
Tm
168.9 70
Yb
173.071
Lu
175.0
90
Th
232.0 91
Pa
231.0 92
U
238.0 93
Np
237.094
Pu
(244) 95
Am
(243) 96
Cm
(247) 97
Bk
(247) 98
Cf
(251) 99
Es
(252) 100
Fm
(257) 101
Md
(258) 102
No
(259) 103
Lr
(260) DATA SHEET
AVOGADRO EXAM 2008
DETACH CAREFULLY
C o n s t a n t s : C o n v e r s i o n f a c t o r s :
NA = 6.022 × 1023 mol−1 1 atm = 101.325 kPa = 760 torr = 760 mm Hg
R = 0.082058 atm L K−1 mol−1 0oC = 273.15 K
= 8.3145 kPa L K−1 mol−1
= 8.3145 J K−1 mol−1
Kw = 1.0×10−14 (at 298 K)
F = 96 485 C mol−1
Equations: PV = nRT k t1/2 = 0.693 pH = pK a + log ( [base] / [acid] ) −± −=24
2bb a cx
a |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2007.pdf | 1 | AVOGADRO EXAM 2007
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
17 MAY 2007 TIME: 75 MINUTES
This exam is being written by several thousand students. Please be sure that you follow the instructions below.
We'll send you a report on your performance. Top performers are eligible for a prize.
1. Print your name here:
2. Print your school name
and city on your STUDENT
RESPONSE sheet.
3. Select, and enter on the STUDENT RESPONSE sheet, one of the following CODE numbers:
Code 1 Ontario , now studying Grade 11 Chemistry
in a nonsemestered school
Code 2 Ontario , now studying Grade 11 Chemistry
in a semestered school
Code 3 Ontario , Grade 11 Chemistry
already completed
Code 4 Any other Ontario student
Code 5 Manitoba or Saskatchewan high school
student
Code 6 Québec high school student
Code 7 not used
Code 8 Alberta or British Columbia high school
student
Code 9 New Brunswick, Newfoundland, Nova Scotia,
or Prince Edward Island high school student
Code 10 Northwest Territories, Nunavut, or Yukon
high school student
Code 11 High school student outside Canada
Code 12 Teacher
4. Print
your name (last name, first name and optional
middle initial) on the STUDENT RESPONSE sheet .
Also fill in the corresponding circles below your printed
name.
5. Carefully detach the last page. It is the datasheet.
6. Now answer the exam questions. Questions are not in
order of difficulty. Indicate your choice on the STUDENT RESPONSE sheet by marking one letter beside the question number.
• Mark only one answer for each question. • Questions are all of the same value. • There is a penalty (1/4 off) for each incorrect
answer, but no penalty if you do not answer.
7. Take care that you make firm, black pencil marks, just
filling the oval.
Be careful that any erasures are complete—make the
sheet white again.
Carefully detach the last page.
It is the Data Sheet. |
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2 / AVOGADRO EXAM © 2007 UNIVERSITY OF WATERLOO 1 Which atom has the most neutrons?
A
F18
9
*B O18
8
C C14
6
D N15
7
E B11
5
2
Which of the following pairs of atomic symbols and
elements is incorrect?
A Fe, iron
B Mg, magnesium
C Ca, calcium
*D Br, boron
E Mn, manganese
3 Which of the following particles is not a charged
particle?
A α-particle
B β-particle
C electron
D proton
*E neutron
4 The formula of a compound is X 2O. Which of the
following is X least likely to be?
*A barium (Ba)
B sodium (Na)
C cesium (Cs)
D hydrogen (H)
E copper (Cu)
5 How many protons are there in the nucleus of I127
53?
A 7
*B 53
C 74
D 127
E 180
6 Which group of elements has the greatest electron
affinity?
A group 14
B group 15
C group 16
*D group 17
E group 18
7 The difference between deuterium, H2
1, and the more
common form hydrogen is that deuterium
A does not occur naturally.
B is radioactive.
C has one more atom per molecule.
D has one more proton in the nucleus.
*E has one more neutron in the nucleus.
8 Which group of atoms and ions contain the same
number of electrons?
A F, Ne, Na
B O2-, S2-, Se2-
C Mg, Al, Si
D Ca2+, Fe3+, Zn2+
*E Cl-, Ar, K+
AVOGADRO EXAM 2007 - Answers |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2007.pdf | 3 |
© 2007 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 3 9 Which of the following is an ionic solid?
A N 2O
B HCl
*C LiCl
D CO 2
E CH 4
10
What volume of CO 2 is produced when you burn
exactly 1.0 litre of gaseous propane (C 3H8) in the
presence of excess oxygen in your backyard
barbecue? Assume H 2O and CO 2 are the only
combustion products and that the pressure and
temperature remain constant.
A 1.0
B 1.5
C 2.0
D 2.5
*E 3.0
11 Polonium-210 (210Po) is radioactive, extremely toxic,
and it decays according to the chemical equation below. What is the missing product in the equation?
210Po → + He4
2
A 214Po
B 212Tl
*C 206Pb
D 214Rn
E 210Po
12
The bubbles in boiling water are mostly
A He
*B H 2O
C CO 2
D N 2
E O 2 13 An element, X, from group 1 of the periodic table,
combines to form a stable compound with an element, Y, from group 16. The formula of that
compound is most likely to be
A X 3Y
B XY 3
C XY
*D X 2Y
E XY 2
14 After a large meal the pH of your stomach drops to
1.78. What is [H+] in your stomach after the meal?
*
A 1.66 x 10-2 mol L-1
B 0.250 mol L-1
C 1.78 mol L-1
D 1.83 x 10-3 mol L-1
E 6.03 x 10-2 mol L-1
15 The chemical formula of barium perrhenate is
Ba(ReO 4)2. What is the charge on the perrhenate ion?
A +2
B +1
C 0
*D -1
E -2
16
These three compounds have been isolated: NaCl,
Na2O, and AlCl 3. What is the formula of aluminum
oxide?
A Al 2O
* B Al 2O3
C Al 3O
D AlO
E AlO 3
? |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2007.pdf | 4 |
4 / AVOGADRO EXAM © 2007 UNIVERSITY OF WATERLOO 17 The average car in Canada uses 0.93 L of gasoline to
go 100 km. If it is assumed that gasoline is pure octane (C
8H18), with a density of 0.70 g/mL and a
molar mass of 114.2 g/mol, then how many moles of
octane are consumed by driving 100 km?
A 0.93 mol
*
B 5.7 mol
C 11 mol
D 5.7 x 10-4 mol
E 1.1 x 10-3 mol
18 How many moles of gas are present in a 15.0-L
scuba tank, if the pressure in the tank is 23.0 MPa
and the temperature is 298 K? Assume the gas behaves ideally.
A 23 mol
B 72 mol
C 44 mol
D 14.1 mol
* E 139 mol
19 Chlorine has two abundant stable isotopes, 35Cl and
37Cl, with atomic masses of 34.97 amu and 36.96 amu
respectively. What is the percent abundance of the
heavier isotope?
A 78%
* B 24%
C 64%
D 50%
E 36%
20 Which of the following is not a gas at 298 K?
A Ar
B He
*C Br 2
D H 2
E O 2 21 Which of the following types of radiation has the
highest energy per photon?
A radio waves
B ultraviolet radiation
C
infrared radiation
*D x-rays
E
purple laser light
22 The Lewis structure (i.e. electron dot) structure for the
HCN molecule is given below.
The bond angle is nearest to
A 60o
B 90o
C 105o
D 120o
*E 180o
23 What volume of 0.100 mol L-1 NaOH( aq) is required to
neutralize 0.245 L of 0.200 mol L-1 H3PO 4(aq)?
A 0.490 L
B 0.500 L
*C 1.47 L
D
2.30 L
E 1.47 mL
24 Which of the following molecules forms hydrogen
bonds amongst themselves?
A dimethyl ether (CH 3OCH 3)
B methane (CH 4)
C hydrogen sulfide (H 2S)
*D ethanol (CH 3CH 2OH)
E formaldehyde (H 2CO)
H C N
1 MPa = 1 ×103 kPa |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2007.pdf | 5 |
© 2007 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 5 25 Aluminum dissolves in acidic solution according to the
chemical equation below.
2 Al( s) + 6 HCl( aq) → 2 AlCl 3(aq) + 3 H 2(g)
How many grams of aluminum (27 g mol-1) are
required to produce 0.50 mol H 2?
A 20 g
*
B 9.0 g
C 14 g
D 27 g
E 0.24 g
26 For which of the following reactions is the change in
energy equal to the first ionization energy of oxygen?
A O-(g) + e- → O2-(g)
B O(g) + 2e- → O2-(g)
* C O(g) → O+(g) + e-
D O(g) + e- → O-(g)
E O( g) → O2+(g) + 2e-
27
How does the pH of a solution change as HCl is
added to a solution of NaOH?
* A The pH decreases and may go below 7.
B The pH will not change.
C The pH decreases until it reaches a value of 7
and then stops.
D The pH increases until it reaches a value of 7 and
then stops.
E The pH increases and may go above 7.
28
The volume of a gas, initially at 1 atm and 20oC, is
increased from 40.0 mL to 80.0 mL. If the pressure remains constant, what is the final temperature of
the gas?
A
40.080.0 K 293+
B ×80.020 C 40.0D
* C
40.080.0 K 293×
D
80.040.0 K 293×
E ×40.020 C 80.0D
29
Which drawing shows a pipet correctly filled for
delivery?
A 1
*B 2
C 3
D 4
E none of the above
30 What is the mass percentage of copper in CuCl 2 ?
A 12.1%
B 64.2%
C 91.2%
D 25.2%
*E 47.3% 1 2 3 4 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2007.pdf | 6 |
6 / AVOGADRO EXAM © 2007 UNIVERSITY OF WATERLOO 31 Which one of the following solutions will be the best
electrical conductor at 25oC?
*A 0.10 mol L−1 Na 2SO 4(aq)
B 0.10 mol L−1 NaCl( aq)
C 0.10 mol L−1 H2SO 4(aq)
D 0.10 mol L−1 HNO 3(aq)
E 0.10 mol L−1 CsCl( aq)
32 What is the coefficient of O 2 when the following
equation is balanced with the smallest whole-number
coefficients?
__Cr 2O3 + ___ KOH + ___O 2 → __K 2CrO 4 + __H 2O
A 2
* B 3
C 4
D 5
E 6
33 What is the oxidation state of N in HNO 2?
A +5
* B +3
C +1
D −1
E −3
34 If the Kelvin temperature of a sample of ideal gas doubles (e.g. from 200 K to 400 K), then the average kinetic energy of the molecules in the sample
A increases by a factor of 2
B decreases by a factor of 2
*C increases by a factor of 2
D increases by a factor of 4
E remains the same
35 The ground state electronic configuration of a certain neutral atom is [Xe] 6s
2 4f14 5d10 6p4. To which group
of the periodic table does this atom belong?
A group 1
B group 3
C group 6
D group 14
*E group 16
36 How many moles of water are there in 1.80 L of
H2O(l) at 1.00 atm and 298 K? The density of water
is 1.00 g/mL at 1.00 atm and 298 K.
A 1.00 mol
B 0.0736 mol
C 55.6 mol
*D 1.00 x 102 mol
E 13.6 mol
37 The reaction 2 Al(s) + 6 HCl(aq) → 2 AlCl 3(aq) + 3 H2(g)
is an example of
A a precipitation reaction
B an acid-base reaction
C a decomposition reaction
*D an oxidation-reduction reaction
E an isomerization reaction
38 If equal volumes of 0.10 mol L-1 solutions of NaOH
and HCl are mixed, what is the pH of the resulting
solution at 298 K?
A 1
B 13
* C 7
D 1.3
E 12.7
This question was NOT marked.
The electron configuration was
mistakenly given as:
[Xe] 6s2 5f14 6d10 6p4 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2007.pdf | 7 |
© 2007 UNIVERSITY OF WATERLOO AVOGADRO EXAM / 7 39 A calcium chloride solution was prepared by
dissolving 11.00 g CaCl 2 in water to make 500 mL of
solution. What is the correct way to report the
concentration of this solution?
*
A 0.2 mol L-1
B 0.1982 mol L-1
C 0.198 mol L-1
D 0.2000 mol L-1
E 0.20 mol L-1
40 A compound of carbon and hydrogen is found to be
85.6 % carbon, by mass, and 14.38% hydrogen. What
is the simplest formula of the compound?
A CH
*
B CH 2
C CH 3
D CH 4
E C 3H4
CaCl 2, 110.98 g mol-1
The number of significant figures in the volume is
ambiguous (i.e. we don’t know if the zeros are significant),
so we must assume the wors t: that the volume is known
only to 1 significant figure. Therefore, we report the
concentration to 1 significant figure only. If the volume had
been recorded as 0.500 L, then we could have given the
concentration as 0.198 mol L−1. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/avogadro-exam-solution-2007.pdf | 8 |
8 / AVOGADRO EXAM © 2007 UNIVERSITY OF WATERLOO
1
1A
18
8A
1
H
1.008
2
2A
13
3A
14
4A
15
5A
16
6A
17
7A 2
He
4.003
3
Li
6.941 4
Be
9.012 5
B
10.816
C
12.01 7
N
14.01 8
O
16.009
F
19.0010
Ne
20.18
11
Na
22.99 12
Mg
24.31
3
3B
4
4B
5
5B
6
6B
7
7B
8
←
9
8B
10
→
11
1B
12
2B 13
Al
26.9814
Si
28.09 15
P
30.97 16
S
32.0717
Cl
35.4518
Ar
39.95
19
K
39.10 20
Ca
40.08 21
Sc
44.96 22
Ti
47.88 23
V
50.94 24
Cr
52.00 25
Mn
54.9426
Fe
55.8527
Co
58.9328
Ni
58.6929
Cu
63.5530
Zn
65.3831
Ga
69.7232
Ge
72.59 33
As
74.92 34
Se
78.9635
Br
79.9036
Kr
83.80
37
Rb
85.47 38
Sr
87.62 39
Y
88.91 40
Zr
91.22 41
Nb
92.91 42
Mo
95.94 43
Tc
(98) 44
Ru
101.145
Rh
102.946
Pd
106.447
Ag
107.948
Cd
112.449
In
114.850
Sn
118.7 51
Sb
121.8 52
Te
127.653
I
126.954
Xe
131.3
55
Cs
132.9 56
Ba
137.3 57
La
138.9 72
Hf
178.5 73
Ta
180.9 74
W
183.9 75
Re
186.276
Os
190.277
Ir
192.278
Pt
195.179
Au
197.080
Hg
200.681
Tl
204.482
Pb
207.2 83
Bi
209.0 84
Po
(209) 85
At
(210) 86
Rn
(222)
87
Fr
(223) 88
Ra
226 89
Ac
227.0 104
Rf 105
Db 106
Sg 107
Bh 108
Hs 109
Mt 110
Uun 111
Uuu 112
Uub 113
Uut
58
Ce
140.1 59
Pr
140.9 60
Nd
144.2 61
Pm
(145) 62
Sm
150.463
Eu
152.0064
Gd
157.365
Tb
158.966
Dy
162.567
Ho
164.968
Er
167.3 69
Tm
168.9 70
Yb
173.071
Lu
175.0
90
Th
232.0 91
Pa
231.0 92
U
238.0 93
Np
237.094
Pu
(244) 95
Am
(243) 96
Cm
(247) 97
Bk
(247) 98
Cf
(251) 99
Es
(252) 100
Fm
(257) 101
Md
(258) 102
No
(259) 103
Lr
(260) DATA SHEET
AVOGADRO EXAM 2007
DETACH CAREFULLY
C o n s t a n t s : C o n v e r s i o n f a c t o r s :
NA = 6.022 × 1023 mol−1 1 atm = 101.325 kPa = 760 torr = 760 mm Hg
R = 0.082058 atm L K−1 mol−1 0oC = 273.15 K
= 8.3145 kPa L K−1 mol−1
= 8.3145 J K−1 mol−1
Kw = 1.0×10−14 (at 298 K)
F = 96 485 C mol−1
Equations: PV = nRT k t1/2 = 0.693 pH = pK a + log ( [base] / [acid] ) −± −=24
2bb a cx
a |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-solution-2011.pdf | 1 |
2 /CHEM 13 NEWS EXAM © 2011 UNIVERSITY OF WATERLOO 1 At 25 oC and 100 kPa, most of the known elements are
A monatomic gases
B diatomic gases
C liquids
*D metallic solids
E non-metallic or semi -metallic solids
2 Which of the following series lists the compounds in
order of increasing boiling point? (from lowest to
highest)
A H2Te < H 2Se < H 2S < H 2O
*B H2S < H2Se < H 2Te < H 2O
C H2S < H 2O < H 2Se < H 2Te
D H2O < H 2S < H 2Se < H 2Te
E H2O < H 2Te < H 2Se < H 2S
3 In which of the following compounds does oxygen
have the highest oxidation state ?
A CsO 2
B H2O
C O2
D H2O2
*E OF 2
4 Which of the following processe s is the most
endothermic ?
A H2O(l) H2O(g)
B F(g) + e− F−(g)
C NaCl(s) 2H O NaCl(aq)
*D Na(g) Na+(g) + e−
E K+(g) + Cl−(g) KCl(s)
5 Which of the following atoms has electrons in its
outermost shell arranged in the configuration 4s2 4p3 ?
Assume each atom is in its lowest energy state .
A Rb
B Kr
*C As
D Cr
E Sb
6 The following reaction reaches equilib rium in a closed
reaction vessel at 200 oC.
CO(g) + 3 H 2(g) CH4(g) + H2O(g), Ho=−206 kJ
Which of the following actions causes the reaction to
proceed from left to right in order to restore
equilibrium?
A increasing the volume of the container , holding
temperature constant
B adding some CH 4 gas to the system, with volume
and temper ature held constant
*C adding some H 2 gas to the system, with volume
and temperature held constant
D increasing the temperature, holding the pressure
constant
E removing some CO gas from the system, with
volume and temperature held constant
7 At a ce rtain temperature, the following equilibrium
constants have been measured.
A2(s) + 2 B(g) 2 C(g) K1 = 36
D(s) + 2 E(g) C(g) K2 = 20
What is the equilibrium constant at the same
temperature for the reaction below ?
½ A 2(s) + B(g) D(s) + 2 E(g)
A 720
B 1.8
C 0.56
*D 0.30
E 0.090
CHEM 13 NEWS EXAM 20 11 - Answers |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-solution-2011.pdf | 2 |
© 2011 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 3 8 In a particular solution , [Br− ] = 0.020 mol L−1 and
[CrO 42− ] = 0.0030 mol L−1. Finely -divided solid silver
nitrate, AgNO 3, is slowly added to the solution. What
is [Br− ] when Ag 2CrO 4(s) just begins to precipitate?
*A 2.1×10−8 mol L−1
B 6.0×10−8 mol L−1
C 2.7×10−7 mol L−1
D 5.2×10−13 mol L−1
E 6.4×10−4 mol L−1
9 What is the formula of the stable compound for med
by magnesium and nitrogen?
A MgN
B Mg 2N
*C Mg 3N2
D Mg 2N3
E MgN 2
10 Which of the following ions has the smallest tendency
to be protonated when dissolved in liquid acetic acid,
CH 3COOH(l)?
A hydroxide,OH−
B fluoride, F−
C chloride, Cl−
D bromide, Br −
*E iodide, I−
11 X-ray radiation is more energetic than microwave
radiation because
A photons of X-ray radiation travel faster than those
of microwave radiation
B photons of X-ray radiation are heavier than those
of microwave radiation
*C X-ray rad iation has a higher frequency than does
microwave radiation
D X-ray radiation has a longer wavelength than
does microwave radiation
E photons of X-ray radiation travel slower than
those of microwave radiation
12 Which of the following contains only single bonds ?
A NO+
B CO
C CN−
D N22−
*E O22−
13 What is the empirical formula of a compound that is
66.64% carbon , 7.45% hydrogen and 25.91%
nitrogen by mass ?
*A C3H4N
B C3H4N2
C C3H3N
D C4H4N
E C4H3N2
14 Let DC=C represent the C=C bond dissociation energy
in ethene, H 2C=CH 2, and DC−C the C -C bond
dissociation energy in ethane, H 3C−CH 3. How do
these bond dissociation energies compare?
A DC=C equals DC−C
B DC=C is exactly equal to 2 × DC−C
C DC=C is exactly equal to ½ × DC−C
*D DC=C is greater than DC−C but less than 2 × DC−C
E DC=C is greater than 2 × DC−C
15 Which of the following bonds is most polar?
A B−O
*B B-F
C C-O
D C=O
E C−F
Ksp
Ag2CrO 4 1.9×10−12
AgBr 5.2×10−13 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-solution-2011.pdf | 3 |
4 /CHEM 13 NEWS EXAM © 2011 UNIVERSITY OF WATERLOO 16 Consider the following energy level diagram for the
reaction R → P.
Which of the following statements is false ?
*A The conversion of R to P occurs via a two-step
process.
B X and Y represent reaction intermediates .
C The conversion of R to P is endothermic.
D At equilibrium, the rate of conversion of R to P is
equal to the rate of conversion of P to R.
E The rate -limiting step is the conversion of X to Y.
17 A solution in which the bromide concentration is
2.0×10−5 mol L−1 is in equilibrium with solid AgBr and
solid AgI. What is the concentration of iodide ion ?
A 2.6×10−8 mol L−1
*B 5.8×10−9 mol L−1
C 1.5×10−16 mol L−1
D 7.5×10−12 mol L−1
E 2.9×10−4 mol L−1
18 Consider the hydrogen halides HF, HCl, H Br and HI.
Which of the statements about them is true?
A They are all strong acids.
B They are all weak acids.
C The boiling point increases with molar mass.
D The bond dissociation energy increases with
molar mass .
*E none of above
19 For the reaction below, Kc = 1.0×10−20.
2 A(g) + B(g) C(g)
In an experiment, 1.0 mol each of A, B and C are
placed in an empty 1.0 L container and then the
container is quickly sealed. When equilibrium is
established, w hich of the following will be true?
A [A] < [B] < [C]
*B [A] > [B] > [C]
C [A] = [B] = [C]
D [A] = [B] < [C]
E [A] > [B] = [C]
20 What percentage of CH 3COOH molecules are ionized
in 1.8×10−5 mol L−1 CH 3COOH(aq) ?
A 1.8%
B 4.2%
C 42%
*D 62%
E almost 100%
21 A technician rec orded the following curve during a
titration.
The curve represents the titration of a
A weak acid by adding strong base
B strong aci d by adding weak base
C strong base by adding weak acid
D strong base by adding strong acid
*E a weak base by adding strong acid Y
R X P
Reaction progress Potential
Energy
Volume of reagent added
from burette (in mL) pH
Ksp
AgBr 5.2×10−13
AgI 1.5×10−16 Ka(CH 3COOH) = 1.8×10−5 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-solution-2011.pdf | 4 |
© 2011 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 5 Use the table of standard reduction potentials
given below to answer questions 22 through 25.
22 Which of the following is the strongest oxidizing agent
under standard conditions ?
*A Ag+(aq)
B Ag(s)
C H+(aq)
D Al(s)
E Al3+(aq)
23 When Ag+(aq) reacts completely with exactly one
mole of H2(g) under stan dard conditions, how many
moles of solid Ag are produced ?
A 1 mol
*B 2 mol
C 0.5 mol
D 4 mol
E 0.25 mol
24 What is Eo for the reaction 2 H2(g) + O2(g) → 2 H2O(l)?
*A 1.23 V
B 0.43 V
C 4.06 V
D 0.43 V
E 2.06 V 25 Which of the following reagents would spontaneously
reduce Ni2+(aq) to Ni(s) under standard conditions ?
A Ag+(aq)
B Ag(s)
*C Zn(s)
D Sn(s)
E Al3+(aq)
26 Consider the ions K+, Ca2+, Cl− and S2−. In which
series are the species listed in order of decreasing
radius? (from largest to smallest)
*A S2− > Cl− > K+ > Ca2+
B K+ > Ca2+ > S2− > Cl−
C S2− > Ca2+ > Cl− > K+
D Ca2+ > K+ > Cl− > S2−
E Ca2+ > K+ > S2− > Cl−
27 A solu tion is prepared by completely dissolving a
solid mixture of NaOH and Mg(OH) 2 in water. For the
resulting solution, which of the following conditions
must be satisfied?
A [Na+ ] = [Mg2+ ] = [OH− ]
B [Na+ ] = [Mg2+ ] = 3 [OH− ]
C [Na+ ] + [Mg2+ ] = 3 [O H− ]
*D [Na+ ] + 2 [Mg2+ ] = [OH− ]
E [Na+ ] + [Mg2+ ] = [OH− ]
28 What is the minimum volume of water needed to
dissolve completely 1.0 g SrF 2?
*A 9.0 L
B 150 L
C 10.5 L
D 5.6 L
E 2.8 L
Half–Reaction Eo
Ag+(aq) + e− Ag(s) +0.80 V
O2(g) + 2 H2O(l) + 4e– 4 OH–(aq) +0.40 V
2 H+(aq) + 2e− H2(g) 0.0 V
Sn2+(aq) + 2e− Sn(s) –0.14 V
Ni2+(aq) + 2e− Ni(s) –0.25 V
Fe2+(aq) + 2e− Fe(s) –0.41 V
Zn2+(aq) + 2e− Zn(s) –0.76 V
2 H2O(l) + 2e− H2(g) + 2 OH−(aq) –0.83 V
Al3+(aq) + 3 e− Al(s) –1.66 V
Ksp(SrF 2) = 2.8×10−9
Sr, 87.62 g mol−1
F, 19.00 g mol−1 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-solution-2011.pdf | 5 |
6 /CHEM 13 NEWS EXAM © 2011 UNIVERSITY OF WATERLOO 29 What is the molecular geometry of SF 4?
A T-shaped
B tetrahedral
*C see-saw
D square planar
E square pyramidal
30 In the incomplete equation below, NH 3 acts as a
Bronsted -Lowry acid and “X” represents a Bronsted -
Lowry base. What is the conjugate base of NH 3?
NH 3 + X → ?
A X
B XH+
C NH 4+
*D NH 2−
E OH−
31 What is the general trend observed for the first
ionization energies of the elements in groups 13
through 17?
A Ionization energies tend to increase from left to
right in a period, and are approximately constant
in a g roup.
*B Ionization energies tend to increase from left to
right in a period, and decrease from top to bottom
in a group.
C Ionization energies tend to decrease from left to
right in a period, and increase from top to bottom
in a group.
D Ionization energies tend to decrease from left to
right in a period, and decrease from top to bottom
in a group.
E Ionization energies are approximately constant in
a period, and decrease from top to bottom in a
group.
32 What is the hybridization of the sulfur atom in the
SO 32− ion?
A sp
B sp2
*C sp3
D sp3d
E sp3d2
33 The phase diagram for an unidentified substance is
shown below.
Which of the following statements is true?
A Liquid can be converted to solid by increasing the
pressure at constant temperature .
B The melting temperature of the solid increases as
pressure increases.
C Solid cannot be converted into gas without first
being converted to liquid.
*D There is only one combination of temperature and
pressure for which solid, liquid and gas can
coexist.
E More than one of the statements above are true.
34 When the following equation is balanced using the
smallest whole number coefficients, what is the
coefficient of O 2?
NH 3 + O 2 → NO + H 2O
A 2
B 3
C 4
*D 5
E 6 Pressure
gas liquid
solid
Temperature |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-solution-2011.pdf | 6 |
© 2011 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 7 35 What is [CH 3COOH] at equilibrium if 0.10 moles of
CH 3COOH and 0.15 moles of NaOH are dissolved in
enough water to make 1.0 L of solution at 25 oC? For
CH 3COOH, Ka = 1.8×10−5 at 25 oC.
A 0 mol L−1
B 1.8×10−5 mol L−1
C 5.6×10−10 mol L−1
*D 1.1×10−9 mol L−1
E 1.3 × 10−3 mol L−1
36 The following diagram is sometimes used to illustrate
the structure of benzene, C 6H6.
Which of the statements concerning the structure of
benzene is false ?
*A The double bonds oscillate rapidly back and forth
between adjacent pairs of carbon atoms.
B The H -C-C angles are 120o.
C The carbon atoms form a flat hexagonal ring.
D The oxidation state of carbon is −1.
E The carbon -carbon bonds are all the s ame length.
37 A particular substance, X, decomposes such that its
concentration decreases by a factor of two every 35 s.
If the initial concentration of X was 1.0 mol L−1, what is
[X] after exactly 140 s?
A 0.33 mol L−1
B 0.13 mol L−1
C 0.25 mol L−1
*D 0.063 mol L−1
E 0.67 mol L−1
38 The bond dissociation energies for F 2 and Cl 2 are
approximately 158 and 242 kJ mol−1, respectively.
Given that the enthalpy change for the reaction below
is ΔH = −54 kJ mol−1, what is the bond dissociation
energy for the F -Cl bond?
½ F2(g) + ½ Cl 2(g) → FCl(g)
A 200 kJ mol−1
*B 254 kJ mol−1
C 146 kJ mol−1
D 454 kJ mol−1
E 346 kJ mol−1
39 Which of the following has the greatest number of
unpaired electrons in its ground electronic state?
A Al
B Cl
*C Ti2+
D Zn2+
E S2−
40 Let HA represent a weak monoprotic acid with
Ka = 1.0×10−5. In an experiment, a 50.0 mL
sample of 0.1 0 mol L−1 HA(aq) is titrated with
0.10 mol L−1 NaOH(aq) . At which point during the
titration are the equi librium concentrations of H+
and OH− equal?
A after the addition of exactly 25.0 mL of NaOH(aq)
*B after the addition of slightly less than 50.0 mL of
NaOH(aq)
C after the addition of exactly 50.0 mL of NaOH(aq)
D after the addition of more than 50.0 m L of
NaOH(aq)
E The equilibrium concentrations of H+ and OH− are
never equal .
|
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2010.pdf | 1 | CHEM 13 NEWS EXAM 2010
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
20 MAY 2010 TIME: 75 MINUTES
This exam is being written by several thousand students. Please be sure that you follow the instructions below.
We'll send you a report on your performance. T op performers are eligible for a prize.
The names of the top 200 students will be published in the September issue of Chem 13 News.
1. Print your name here:
2. Print your school name
and city on your STUDENT
RESPONSE sheet.
3. Select, and enter on the STUDENT RESPONSE sheet, one of the following CODE numbers:
Code 1 Ontario , now studying Grade 12 Chemistry
in a nonsemestered school
Code 2 Ontario , now studying Grade 12 Chemistry
in a semestered school
Code 3 Ontario , Grade 12 Chemistry
already completed
Code 4 Any other Ontario student
Code 5 Manitoba or Saskatchewan high school
student
Code 6 Québec high school student
Code 7 Québec CEGEP student
Code 8 Alberta or British Columbia high school
student
Code 9 New Brunswick, Newfoundland, Nova Scotia,
or Prince Edward Island high school student
Code 10 Northwest Territories, Nunavut, or Yukon
high school student
Code 11 High school student outside Canada
Code 12 Teacher
4. Print
your name (last name, first name and optional
middle initial) on the STUDENT RESPONSE sheet .
Also fill in the corresponding circles below your printed
name.
5. Carefully detach the last page. It is the datasheet.
6. Now answer the exam questions. Questions are not in
order of difficulty. Indicate your choice on the STUDENT RESPONSE sheet by marking one letter beside the question number.
• Mark only one answer for each question. • Questions are all of the same value. • There is a penalty (1/4 off) for each incorrect
answer, but no penalty if you do not answer.
7. Take care that you make firm, black pencil marks, just
filling the oval.
Be careful that any erasures are complete—make the
sheet white again.
Carefully detach the last page.
It is the Data Sheet. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2010.pdf | 2 |
2 /CHEM 13 NEWS EXAM © 2010 UNIVERSITY OF WATERLOO 1 Of the first 18 elements, how many are gases at
25 oC and 100 kPa?
A less than seven
B seven
*C eight
D nine
E more than nine
2 Which of the following substances has the highest
vapour pressure at 25 oC?
A CH
3OH
B CH 3CH 2CH 2OH
C LiF
*D H 2CO
E Li
3 Which of the following compounds has the highest
melting point?
A LiF
*B ZnO
C LiCl
D NaF
E NaCl
4 For a given substance, which of the following phase
transitions is the most exothermic?
A solid → liquid
B gas → liquid
C liquid → gas
D solid → gas
*E gas → solid
5 What is the ground state electron configuration of
selenium, Se?
A 1s
2 2s2 2p6 3s2 3p6 4s2 4p4
B 1s2 2s2 2p6 3s2 3p6 3d10 4p6
*C 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p4
D 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6
E 1s2 2s2 2p6 3s2 3p6 4s2 4p4 4d10 6 The reaction below reaches equilibrium in a closed
reaction vessel.
C 6H12O6(s) 2 C 2H5OH(l) + 2 CO 2(g), ∆Ho = −72 kJ
Which of the following actions causes an increase in
the value of Kc?
(i) adding some CO 2(g)
(ii) transferring the reaction mixture to a vessel of
larger volume
(iii) increasing the temperature
A (i) only
B (ii) only
C (iii) only
D (i) and (ii)
*E none of the above
7 Given that
2 Hg
2+(aq) + 2 e− Hg 22+(aq) E o = 0.920 V
Ag+(aq) + e− Ag(s) E o = 0.799 V
what is E o for the reaction below?
2 A g+(aq) + Hg 22+(aq) 2 Ag(s) + 2 Hg2+(aq)
A 0.121 V
*B −0.121 V
C 0.678 V
D −0.678 V
E 0.339 V
8 Given that
F e2+(aq) + 2 e− Fe(s) E o = −0.40 V
2 H+(aq) + 2 e− H2(g) E o = 0.00 V
B r 2(l) + 2 e− 2 Br−(aq) E o = +1.09 V
which of the following is the strongest reducing agent
under standard conditions?
A Fe2+(aq)
B H+(aq)
C Br 2(l)
D Br−(aq)
*E H 2(g)
CHEM 13 NEWS EXAM 2010 - Answers
Ionic Radii (in pm)
Li+, 68 F−, 136
Zn2+, 74 O2−, 140
Na+, 97 Cl−, 181 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2010.pdf | 3 |
© 2010 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 3 9 What is the coefficient of O 2 when the following
equation is balanced?
1 C 10H8(s) + x O2(g) → y CO 2(g) + z H2O(l)
A 1
B 6
C 7
*D 12
E 14
10 Which of the following will react appreciably with
water at room temperature and pressure to produce
hydrogen?
*A NaH
B NH
3
C CH 4
D HCl
E H 2S
11 Cesium forms a number of compounds with oxygen.
A particular compound is found to be 26.5% oxygen
by mass. What is the formula of this compound?
A Cs 2O
B Cs 2O2
C CsO 2
*D CsO 3
E CsO 4
12 Which of the following is the strongest acid in water?
A HBr
B HOBrO
2
C HF
D HOIO 2
*E HI
13 Let the energy of the 2s level in a hydrogen atom
be –E. What is the energy of the 3s level?
A
E23
*B E49
C E32
D E94
E E3
14 Natural oils, such as vegetable oil, are converted into
solid, edible fats by a process called
A fusion
*B hydrogenation
C crystallization
D flash freezing
E saponification
15 The value for the activation energy of the forward
reaction is represented by which letter in the diagram
below?
* A A
B B
C C
D D
E E
reactants
productsA
C
B E
D
Reaction progress Energy Molar masses
(in g/mol)
O, 16.00
Cs, 132.9 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2010.pdf | 4 |
4 /CHEM 13 NEWS EXAM © 2010 UNIVERSITY OF WATERLOO 16 The heat of combustion of C(s) is −394 kJ/mol and
that of CO(g) is −111 kJ/mol. What is the enthalpy
change for the reaction below?
CO(g) → C(s) + ½ O 2(g)
A 505 kJ
* B 283 kJ
C 111 kJ
D −283 kJ
E −505 kJ
17 Exactly 850 mL of O
2 gas is collected over water at
30.0 oC using the setup below. Given that the
barometric pressure was 98.5 kPa and the vapour
pressure of water is 4.24 kPa at 30 oC, what volume
would the pure O 2 gas occupy at 98.5 kPa and 30 oC?
* A 813 mL
B 818 mL
C 850 mL
D 882 mL
E 888 mL
18 How are the boiling and freezing points of water
affected by the addition of a soluble salt?
A The freezing and boiling points are both lowered.
B The freezing and boiling points are both raised.
* C The freezing is lowered and the boiling point is
raised.
D The freezing is raised and the boiling point is
lowered.
E The boiling and freezing po ints are not affected.
19 The reaction below comes to equilibrium in a closed
reaction vessel of volume 2.50 L.
2 NO
2(g) 2 NO(g) + O 2(g)
At equilibrium, there are 3.0 mol NO, 4.00 mol O 2 and
22.0 mol NO 2. What is the value of Kc for the reaction
above?
*A 0.0298
B 33.6
C 1.83
D 13.4
E 0.218
20 Which of the following occurs if a 0.10 mol/L solution
of a weak acid is diluted to 0.010 mol/L at constant temperature?
A The hydrogen ion concentration decreases to
0.010 mol/L.
B The pH decreases.
C The ionization constant,
Ka, decreases.
*D The percentage ionization increases.
E all of the above
21 What is the equilibrium concentration of Ag
+ in
solution when 0.50 L of 0.10 mol/L AgNO 3(aq) and
0.50 L of 0.20 mol/L NaCl(a q) are mixed? Assume the
temperature is 25 oC.
A 0 mol/L
* B 3.6×10−9 mol/L
C 9.0×10−10 mol/L
D 1.3×10−5 mol/L
E 0.05 mol/L
22 In which ionic compound does the cation have the
same number of electrons as the anion?
A LiF
B NaCl
C CaO
*D MgF 2
E KI
O2(g)
water
For AgCl, Ksp = 1.8×10−10
at 25 oC. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2010.pdf | 5 |
© 2010 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 5 23 How many moles of NaOH or HCl should be added to
1.0 L of 0.010 mol L−1 formic acid (HCOOH) solution
to obtain a solution with pH = 3.50? Assume no
change in volume. (Choose the closest value.)
*A 3.6×10
−3 mol NaOH
B 3.6×10−3 mol HCl
C 5.8×10−3 mol NaOH
D 5.8×10−3 mol HCl
E 3.2×10−4 mol HCl
24 For the reaction below, Kc = 6.3×104 at 25 oC.
2 NO(g) + Cl 2(g) 2 NOCl(g)
In an experiment, carried out at 25 oC, 1.0 mol NO
and 1.0 mol Cl 2 are added to an evacuated reaction
vessel of volume 1.0 L and then the vessel is quickly
sealed. What is the equilibrium concentration of NO?
A 0.50 mol/L
*B 5.6×10−3 mol/L
C 2.8×10−3 mol/L
D 1.6×10
−5 mol/L
E 7.9×10−6 mol/L
25 What is the molecular geometry of the BrF
3 molecule?
The Br atom is the central atom and all the F atoms
are bonded directly to Br.
A trigonal planar
B trigonal bipyramidal
* C T-shaped
D square planar
E trigonal pyramidal
26 When 0.012 moles of a monoprotic acid is dissolved in
water to give 1.0 L of solution at 25
oC, the final pH is
1.95. What is Ka for this acid?
A 2.9×10−1
B 1.1×10−2
* C 1.6×10
−1
D 1.3×10−4
E 1.5×10−6
27 A 1.00 mol/L solution of Cu(NO 3)2(aq) is electrolyzed
using the setup illustrated below . What is the reaction
occurring at the anode?
A Cu
2+(aq) + 2 e− → Cu(s)
B Cu(s) → Cu2+(aq) + 2 e−
C 2 H 2O(l) + 2 e− → H 2(g) + 2 OH−(aq)
*D 2 H 2O(l) → O2(g) + 4 H+(aq) + 4 e−
E Pt(s) → Pt4+(aq) + 4 e−
28 Which of the following forms of radiation has the
longest wavelength?
A infrared
B x-ray
* C microwave
D ultraviolet
E visible
Ka = 1.8×10−4 for HCOOH
Cu(s)
Cu(NO 3)2(aq) battery
Pt(s) − + |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2010.pdf | 6 |
6 /CHEM 13 NEWS EXAM © 2010 UNIVERSITY OF WATERLOO 29 In the unbalanced chemical equation below, x, y and
z are coefficients to be determined.
1 Fe2+ + x Br2 → y Fe3+ + z Br −
When the equation is properly balanced, what is the
value of z?
*A 1
B 2
C
12
D 4
E 14
30 If the pH of a solution changed from 4.0 to 8.0, what
happened to the hydrogen ion concentration?
A It increased by a factor of two.
B It decreased by a factor of two.
C It increased by a factor of 104.
*D It decreased by a factor of 104.
E It decreased by a factor of 102.
31 Which of the following compounds displays only
covalent bonding?
A NH
4OH
B Li2O
* C HOCN
D NaNO
3
E KH
32 How many sigma ( σ) and pi ( π) bonds are there in the
allene molecule, H 2CCCH 2?
* A six σ bonds and two π bonds
B two σ bonds and six π bonds
C four σ bonds and four π bonds
D eight σ bonds and no π bonds
E two σ bonds and six π bonds 33 What is the oxidation state of each sulfur atom in the
peroxydisulfate ion, S 2O82−? In the structure below,
lone pairs are not shown.
A −2
B 0
C +4
* D +6
E +7
34 A Lewis structure for POCl
3 is shown below.
Which of the following statements is correct?
A This is most important Lewis structure for the
POCl
3 molecule.
B The phosphorus atom is sp2-hybridized.
C The Cl-P-Cl angles are 90
o.
D The oxidation state of phosphorus is +4.
* E None of the statements above are true.
35 What is the maximum number of electrons that can
have a principal quantum number of 4 within one atom?
A two
B four
C eight
D sixteen
* E thirty-two OSO
OO O SO
O
O2
PO
Cl
ClCl |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2010.pdf | 7 |
© 2010 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 7 36 How many unpaired electrons are there in a Mn2+ ion in
its ground electronic state? The atomic number of manganese is Z = 25 .
A 0
B 2
C 3
* D 5
E 6
37 The skeletal structure below for the CH
2CHOCN
molecule is incomplete; additional bonding pairs or
lone pairs must be added. When the structure is
properly completed, how many lone pairs are there in this molecule?
A none
B one
C two
* D three
E four
38 When temperature is increased, the rate of a reaction
also increases. This obse rvation is best explained by
A an increase in the frequency of molecular
collisions
B a decrease in the activation energy,
Ea, for the
reaction
C an increase in the activation energy, Ea, for the
reaction
D a decrease in the enthalpy change, ∆H, for the
reaction
* E an increase in the fraction of molecules that have
enough energy to react
39 Which of the following would need the smallest
quantity of heat to change the temperature of 5 g by 10°C?
A I
2(s)
B H2O(l)
* C Au(s)
D He(g)
E Cu(s)
40 Let HA represent a weak monoprotic acid with
Ka = 1.0×10−5. What is the pH at the equivalence
point in the titration of 50. 0 mL of 0.20 mol/L HA(aq)
with 0.20 mol/L NaOH(aq)?
A 5.00
*B 9.00
C 7.00
D 3.00
E 11.00
Specific Heat
(in J g−1 °C−1)
I2(s) 0.158
H2O(l) 4.18
Au(s) 0.129 He(g) 5.19
Cu(s) 0.385
HC
HC
HO C N |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2010.pdf | 8 |
8 /CHEM 13 NEWS EXAM © 2010 UNIVERSITY OF WATERLOO
DATA SHEET
CHEM 13 NEWS EXAM 2010
DETACH CAREFULLY
C o n s t a n t s : C o n v e r s i o n f a c t o r s :
NA = 6.022 1023 mol1 1 atm = 101.325 kPa = 760 torr = 760 mm Hg
R = 0.082058 atm L K1 mol1 0oC = 273.15 K
= 8.3145 kPa L K1 mol1
= 8.3145 J K1 mol1
Kw = 1.0×10−14 (at 298 K)
F = 96 485 C mol−1
Equations: PV = nRT k t1/2 = 0.693 pH = pK a + log ( [base] / [acid] ) 24
2bb a cx
a
1
1A
18
8A
1
H
1.008
2
2A
13
3A
14
4A
15
5A
16
6A
17
7A 2
He
4.003
3
Li
6.941 4
Be
9.012 5
B
10.816
C
12.01 7
N
14.01 8
O
16.009
F
19.0010
Ne
20.18
11
Na
22.99 12
Mg
24.31
3
3B
4
4B
5
5B
6
6B
7
7B
8
9
8B
10
11
1B
12
2B 13
Al
26.9814
Si
28.09 15
P
30.97 16
S
32.0717
Cl
35.4518
Ar
39.95
19
K
39.10 20
Ca
40.08 21
Sc
44.96 22
Ti
47.88 23
V
50.94 24
Cr
52.00 25
Mn
54.9426
Fe
55.8527
Co
58.9328
Ni
58.6929
Cu
63.5530
Zn
65.3831
Ga
69.7232
Ge
72.59 33
As
74.92 34
Se
78.9635
Br
79.9036
Kr
83.80
37
Rb
85.47 38
Sr
87.62 39
Y
88.91 40
Zr
91.22 41
Nb
92.91 42
Mo
95.94 43
Tc
(98) 44
Ru
101.145
Rh
102.946
Pd
106.447
Ag
107.948
Cd
112.449
In
114.850
Sn
118.7 51
Sb
121.8 52
Te
127.653
I
126.954
Xe
131.3
55
Cs
132.9 56
Ba
137.3 57-71
La-Lu 72
Hf
178.5 73
Ta
180.9 74
W
183.9 75
Re
186.276
Os
190.277
Ir
192.278
Pt
195.179
Au
197.080
Hg
200.681
Tl
204.482
Pb
207.2 83
Bi
209.0 84
Po
(209) 85
At
(210) 86
Rn
(222)
87
Fr
(223) 88
Ra
226 89-103
Ac-Lr 104
Rf 105
Db 106
Sg 107
Bh 108
Hs 109
Mt 110
Ds 111
Sg 112
Cn
57
La
138.9 58
Ce
140.1 59
Pr
140.9 60
Nd
144.2 61
Pm
(145) 62
Sm
150.463
Eu
152.0064
Gd
157.365
Tb
158.966
Dy
162.567
Ho
164.968
Er
167.3 69
Tm
168.9 70
Yb
173.071
Lu
175.0
89
Ac
227. 90
Th
232.0 91
Pa
231.0 92
U
238.0 93
Np
237.094
Pu
(244) 95
Am
(243) 96
Cm
(247) 97
Bk
(247) 98
Cf
(251) 99
Es
(252) 100
Fm
(257) 101
Md
(258) 102
No
(259) 103
Lr
(260) |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2009.pdf | 1 | CHEM 13 NEWS EXAM 2009
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
14 MAY 2009 TIME: 75 MINUTES
This exam is being written by several thousand students. Please be sure that you follow the instructions below.
We'll send you a report on your performance. T op performers are eligible for a prize.
The names of the top 200 students will be published in the September issue of Chem 13 News.
1. Print your name here:
2. Print your school name
and city on your STUDENT
RESPONSE sheet.
3. Select, and enter on the STUDENT RESPONSE sheet, one of the following CODE numbers:
Code 1 Ontario , now studying Grade 12 Chemistry
in a nonsemestered school
Code 2 Ontario , now studying Grade 12 Chemistry
in a semestered school
Code 3 Ontario , Grade 12 Chemistry
already completed
Code 4 Any other Ontario student
Code 5 Manitoba or Saskatchewan high school
student
Code 6 Québec high school student
Code 7 Québec CEGEP student
Code 8 Alberta or British Columbia high school
student
Code 9 New Brunswick, Newfoundland, Nova Scotia,
or Prince Edward Island high school student
Code 10 Northwest Territories, Nunavut, or Yukon
high school student
Code 11 High school student outside Canada
Code 12 Teacher
4. Print
your name (last name, first name and optional
middle initial) on the STUDENT RESPONSE sheet .
Also fill in the corresponding circles below your printed
name.
5. Carefully detach the last page. It is the datasheet.
6. Now answer the exam questions. Questions are not in
order of difficulty. Indicate your choice on the STUDENT RESPONSE sheet by marking one letter beside the question number.
• Mark only one answer for each question. • Questions are all of the same value. • There is a penalty (1/4 off) for each incorrect
answer, but no penalty if you do not answer.
7. Take care that you make firm, black pencil marks, just
filling the oval.
Be careful that any erasures are complete—make the
sheet white again.
Carefully detach the last page.
It is the Data Sheet. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2009.pdf | 2 |
2 /CHEM 13 NEWS EXAM © 2009 UNIVERSITY OF WATERLOO 1 In the third period of the elements, how do the atomic
radii of the elements vary?
A The radii increase steadily from Na to Ar.
B The radii increase from Na to Al and decrease
from Al to Ar.
C There is no regular pattern.
D The radii decrease from Na to S and increase
from S to Ar.
*E The radii decrease steadily from Na to Ar.
2 Which of the following compounds has the highest
boiling point?
3 Nitrous acid, HNO
2, is a weak acid in water. Which of
the following statements concerning NO 2− is true?
*A NO 2− is a weak base.
B NO 2− is a strong base.
C NO 2− is a weak acid.
D NO 2− is a strong acid.
E NO 2− is neither an acid nor a base.
4 How many moles of NaOH should be added to 1.0 L
of 0.10 mol L−1 HCOOH( aq) to obtain a solution
having a final pH of 4.0 at 298 K? Assume no change
in volume. (Choose the closest value.)
A 0.018 mol
B 1.8 mol
C 0.26 mol
*D 0.064 mol
E 0.0099 mol
5 Which of the following molecules do not
form
hydrogen bonds amongst themselves?
A CH 3COOH
B H2O2
*C CH 3OCH 3
D HF
E CH
3CH 3OH
6 The reaction below reaches equilibrium in a closed
reaction vessel.
4 HCl( aq) + MnO 2(s)
U Cl 2(g) + 2 H 2O(l) + Mn2+(aq) + 2 Cl−(aq), ΔH < 0
Which of the following actions increases the mass of
Cl2(g) in the equilibrium mixture?
A adding some MnO 2(s)
B increasing the temperature
C adding some MnCl 2(s)
D decreasing the volume of the reaction vessel
*E adding something that precipitates Mn
2+
Ka = 1.8×10−4 at 298 K
for HCOOH. CHEM 13 NEWS EXAM 2009 - Answers
Ka = 7.2×10−4 at
298 K for HNO 2. CC
CH3Cl CH3
Cl
CC
CH3Cl Cl
CH3
CC ClA
B
C
DCH3CC C H3
Cl
CC
CH3CH3 CH3
CH3E* |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2009.pdf | 3 |
© 2009 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 3
7 What is
oE for the cell described above?
A 0.15 V
*B 0.91 V
C 2.43 V
D 3.49 V
E 6.53 V
8 In the cell described above, where does reduction
occur?
A at the aluminum electrode
*B at the zinc electrode
C at the voltmeter
D in the salt bridge
E in the aluminum nitrate solution
9 Considering the standard reduction potentials given in
the box on the right, which of the following is the strongest reducing agent under standard conditions?
*A Al(s)
B Al3+(aq)
C Zn( s)
D Zn2+(aq)
E impossible to determine
10 What is E
cell equal to when the cell described in the
box reaches equilibrium at 25 oC?
A −2.43 V
B +5.62 V
*C 0 V
D 1.06 V
E none of the above
11 A compound is 54.6% C, 36.2% O and 9.2% H by
mass. What is the empirical formula of the
compound?
A CH 2O
*B C 2H4O
C C 3H6O2
D C 4H4O
E C 6H6O
12 What is the pH of a 1.25 ×10−7 mol L−1 HCl( aq)?
A 6.90
*B 6.74
C 7.00
D 6.67
E less than 6.67
Use the following information and diagram
to answer questions 7-10.
A galvanic cell is constructed by placing a strip of zinc into a 1.0 mol L
−1 solution of zinc nitrate
and a strip of aluminum into a 1.0 mol L−1
solution of aluminum nitrate. The two metal strips are connected to a voltmeter by wires
and a salt bridge connects the solutions. (See
the diagram below.) The temperature is 25
oC.
The following standard reduction potentials
apply:
Al3+(aq) + 3e– U Al(s) oE= −1.67 V
Zn2+(aq) + 2e– U Zn( s) oE= −0.76 V
Zn(s) Al(s)
1.0 mol L−1
Zn(NO 3)2(aq) 1.0 mol L−1
Al(NO 3)3(aq) salt bridge Voltmete r |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2009.pdf | 4 |
4 /CHEM 13 NEWS EXAM © 2009 UNIVERSITY OF WATERLOO 13 Which of the following statements is true?
A A single covalent bond consists of a single
delocalized electron.
B For a bond formed between a given pair of atoms,
the bond dissociation energy increases as the
bond order decreases.
C The bond dissociation energy for a C=C bond is
twice that of a C −C bond.
D A polar covalent bond results from the transfer of
one or more electrons from one atom to another.
*E none of the above
14 How many isomers are there for C 5H12?
A one
B two
*C three
D four
E more than four
15 The enthalpy change for the reaction below is
ΔH = −58 kJ (per mole of N
2O4 formed).
2 NO 2(g) + 2 I−(aq)
−⎯⎯→←⎯⎯k
k1
1 2 N 2O4(aq) + I 2(s)
If k1 and k−1 are the rate constants for the forward
and reverse reactions, respectively, and Kc is the
equilibrium constant for the reaction as written, then what effect does increasing the temperature have on
the values of k
1, k−1 and Kc?
A k1 increases, k−1 decreases, Kc increases
B k1 increases, k−1 increases, Kc increases
* C k
1 increases, k−1 increases, Kc decreases
D k1 increases, k−1 decreases, Kc decreases
E k1 decreases, k−1 decreases, Kc decreases
16 Consider the thermochemical equations below.
C
2H4(g) + 3 O 2(g) → 2 CO 2(g) + 2 H 2O(l)
ΔH° = −1411 kJ (per mol C 2H4)
2 C(s) + 3 H 2 (g) + ½ O 2(g) → C 2H5OH(l)
ΔH° = −278 kJ (per mol C 2H5OH)
C2H4(g) + H 2O(l) → C2H5OH(l)
ΔH° = −44 kJ (per mol C 2H4)
What is ΔH° for the following reaction? All the
answers below are for the combustion of one mole of
C2H5OH.
C2H5OH(l) + 3 O 2(g) → 2 CO 2(g) + 3 H 2O(l)
A −1089 kJ
B 632 kJ
C −1455 kJ
D −1733 kJ
*E −1367 kJ
17 A 10.0-L gas cylinder contains neon gas with a
measured pressure of 5.50 atm at 298 K. The 10.0-L
cylinder is then connected to an empty gas cylinder of unknown volume, and the neon gas expands to fill
both cylinders. If the final pressure is found to be
3.76 atm at 298 K, then what is the volume of the second cylinder?
A 14.6 L
B 6.52 L
C 10.0 L
* D 4.63 L
E 9.26 L
18 Which of the following correctly describes what
happens when aqueous solutions of ammonium
carbonate, (NH
4)2CO 3, and potassium bromide, KBr,
are mixed?
A Br− neutralizes NH 4+.
B K2CO 3(s) precipitates.
C HBr is formed.
D NH
4Br(s) precipitates.
* E none of the above
|
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2009.pdf | 5 |
© 2009 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 5
19 For the titration descri bed above, which of the
following is true at the equivalence point?
A [HA] = [Na
+]
B [A− ] = [HA]
* C [Na+ ] = [A− ]
D [H+] = [OH−]
E [A− ] = [H+]
20 Based on the titration curve above, what was the
concentration of the original sample solution (i.e.
before the titration started)?
A 0.63 mol L
−1
*B 0.15 mol L−1
C 0.24 mol L−1
D 0.067 mol L−1
E 0.20 mol L−1
21 Based on the titration curve above, what is the
ionization constant ( Ka) for the acid, HA?
A 10−12.40
B 10−8.91
* C 10−4.89
D 10−2.86
E 10+2.86
22 How many unpaired electron s are there in the nickel
(Ni) atom in its ground state electron state?
A 5
B 4
C 6
*D 2
E 0
23 Equal volumes of 0.1 mol L−1 HCl( aq) and 0.1 mol L−1
HF(aq) are titrated in separate experiments with
0.1 mol L−1 NaOH( aq). Which of the following would be
equal for both titrations?
A the initial pH (i.e. the pH before any NaOH
is added)
B the pH when half the acid has been neutralized
(i.e. the pH at the half-neutralization point)
C the pH at the equivalence point
*D the volume of NaOH required to reach the
equivalence point
E none of the above
24
For the reaction below, Kc = 7.8 ×108. What is the
equilibrium concentration of NH 3 when 1.00 mol each
of Zn(NO 3)2 and NH 3 are dissolved in water to make
1.0 L of solution?
Z n2+(aq) + 4 NH 3(aq) U Zn(NH 3)42+(aq)
A 0 mol L−1
B 1.3×10−9 mol L−1
C 0.75 mol L−1
D 0.25 mol L
−1
*E 4.5×10−3 mol L−1
Use the information and diagram below to answer
questions 19-21.
A 40.0-mL sample of a weak monoprotic acid, HA, is
titrated with 0.20 mol L
−1 NaOH( aq). The titration curve
is shown below.
02468101214
0 1 02 03 04 05 0VNaOH (in mL)pHpH = 12.40
pH = 8.91
pH = 4.89
pH = 2.86 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2009.pdf | 6 |
6 /CHEM 13 NEWS EXAM © 2009 UNIVERSITY OF WATERLOO 25 Which of the following molecules is polar?
A CS
2
* B N 2O
C CCl 4
D PF
5
E SO 3
26 Consider the compounds NaCl, AgCl and CO
2 in terms
of their solubilities in water. Which of these
compounds exhibits an increase in solubility if the temperature is lowered and the pressure is increased?
A NaCl only
B AgCl only
* C CO
2 only
D NaCl and AgCl
E NaCl, AgCl and CO 2
27 When a 1.00 mol L−1 solution of M2+(aq) is
electrolyzed with a current of 2.5 amperes for
0.2 hours, 0.485 g of M( s) are deposited. What is the
identity of M? (Note: 1 ampere = 1 C s−1)?
*A Cr
B Rh
C Na
D Mg
E Ag
28 Iron (III) oxide, Fe
2O3, reacts with hydrochloric acid to
produce only water and a salt . What is the formula of
the salt?
* A FeCl 3
B FeCl
2
C FeCl
D Fe2Cl3
E FeCl 6
29 The unbalanced chemical equation for the oxidation
of Zn by NO 3− is given below. The reaction occurs in
aqueous basic solution.
Zn + NO 3− → Zn(OH) 42− + NH 3
How many moles of NO 3− are required to oxidize
exactly one mole of Zn?
A 1 mol
* B ¼ mol
C 4 mol
D 8 mol
E ⅛ mol
30 Two students each made four measurements of the
mass of an object. Their results are shown in the
table below.
Student A Student B
Measurements: 51.6 g 50.1 g
50.8 g 49.6 g
52.2 g 51.0 g 5 0 . 2 g
49.4 g
Average: 51.3 g 50.0 g
If the exact mass of the object is 51.0 g, then which
of the following statements is true?
A Student A’s results are more accurate and more
precise.
B Student B’s results are more accurate and more
precise.
*C Student A’s results are more accurate but less
precise.
D Student B’s results are more accurate but less
precise.
E The two sets of results are equally precise.
31 Which of the following compounds displays the
greatest ionic character in its bonds?
A NO
2
B CO 2
* C H 2O
D NH
3
E F 2O
|
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2009.pdf | 7 |
© 2009 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 7 32 What is the oxidation state of oxygen in FOCN? The
molecular structure of FOCN is shown below.
*A zero
B +2
C −2
D +1
E −1
33 Experiment shows that in the formamide molecule,
H
2NCHO, the H-N-H angle is 119o and the N-C-O
angle is 124o. Which of the following structures is an
acceptable structure for H 2NCHO and is consistent
with the experimentally-determined bond angles?
A
B
C
* D
E
34 Which of the following best describes the bonding in
the N
2 molecule?
A one σ bond and one π bond
B two σ bonds and one π bond
C two π bonds
D three π bonds
* E one σ bond and two π bonds
35 When building up the electron configuration of a
neutral atom, which orbital fills immediately after the 5s orbital?
* A 4d
B 4f
C 5p
D 6s
E 5d
36 Perovskite is a mineral containing Ca, O and Ti. The
smallest repeating unit in the structure of perovskite is shown below. (There is a single titanium atom at the centre of the cube.) By considering the total number of atoms of each type that lie inside
the cube below,
determine the formula of perovskite. What is the formula of perovskite?
A CaOTi
B CaO
6Ti
C Ca
8O6Ti
D Ca 2O3Ti
* E CaO 3Ti
FOCN
Ca O Ti HNH
CO
H
HNH
CO
H
HNH
CO
H
HNH
CO
H
HNH
CO
H |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2009.pdf | 8 |
8 /CHEM 13 NEWS EXAM © 2009 UNIVERSITY OF WATERLOO 37 Consider the Lewis structure shown below for the
polyatomic ion, EOF 22−. The central atom, E, is an
unidentified element. Which of the following atoms
could E represent?
A oxygen (O)
* B sulfur (S)
C bromine (Br)
D nitrogen (N)
E xenon (Xe)
38 Consider the following reaction mechanism.
(CH
3)3CBr R (CH 3)3C+ + Br −
(CH 3)3C+ + N 3− → (CH 3)3CN 3
According to this mechanism, (CH 3)3C+ is
A a reaction product
* B a reaction intermediate
C an activated complex
D a catalyst
E a Lewis base
39 What is the final temperature when 100.0 mL of
water at 90.0 °C and 200.0 mL of water at 10.0 °C
are mixed? Assume no heat is lost to the surroundings. Choose the closest value.
* A 40
oC
B 50 oC
C 70
oC
D 80 oC
E 100 oC
40 Which of the following is present in the greatest
number in a dilute sulfuric acid (H
2SO 4) solution?
A H2SO 4 molecules
B HSO 4− ions
C SO 42− ions
*D H+ ions
E OH− ions
Properties of water
density = 1.0 g mL−1
specific heat = 4.18 J g−1 oC−1
heat of vaporization = 2260 J g−1 F EO
F2− |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2009.pdf | 9 |
© 2009 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 9
1
1A
18
8A
1
H
1.008
2
2A
13
3A
14
4A
15
5A
16
6A
17
7A 2
He
4.003
3
Li
6.941 4
Be
9.012 5
B
10.816
C
12.01 7
N
14.01 8
O
16.009
F
19.0010
Ne
20.18
11
Na
22.99 12
Mg
24.31
3
3B
4
4B
5
5B
6
6B
7
7B
8
←
9
8B
10
→
11
1B
12
2B 13
Al
26.9814
Si
28.09 15
P
30.97 16
S
32.0717
Cl
35.4518
Ar
39.95
19
K
39.10 20
Ca
40.08 21
Sc
44.96 22
Ti
47.88 23
V
50.94 24
Cr
52.00 25
Mn
54.9426
Fe
55.8527
Co
58.9328
Ni
58.6929
Cu
63.5530
Zn
65.3831
Ga
69.7232
Ge
72.59 33
As
74.92 34
Se
78.9635
Br
79.9036
Kr
83.80
37
Rb
85.47 38
Sr
87.62 39
Y
88.91 40
Zr
91.22 41
Nb
92.91 42
Mo
95.94 43
Tc
(98) 44
Ru
101.145
Rh
102.946
Pd
106.447
Ag
107.948
Cd
112.449
In
114.850
Sn
118.7 51
Sb
121.8 52
Te
127.653
I
126.954
Xe
131.3
55
Cs
132.9 56
Ba
137.3 57
La
138.9 72
Hf
178.5 73
Ta
180.9 74
W
183.9 75
Re
186.276
Os
190.277
Ir
192.278
Pt
195.179
Au
197.080
Hg
200.681
Tl
204.482
Pb
207.2 83
Bi
209.0 84
Po
(209) 85
At
(210) 86
Rn
(222)
87
Fr
(223) 88
Ra
226 89
Ac
227.0 104
Rf 105
Db 106
Sg 107
Bh 108
Hs 109
Mt 110
Uun 111
Uuu 112
Uub 113
Uut
58
Ce
140.1 59
Pr
140.9 60
Nd
144.2 61
Pm
(145) 62
Sm
150.463
Eu
152.0064
Gd
157.365
Tb
158.966
Dy
162.567
Ho
164.968
Er
167.3 69
Tm
168.9 70
Yb
173.071
Lu
175.0
90
Th
232.0 91
Pa
231.0 92
U
238.0 93
Np
237.094
Pu
(244) 95
Am
(243) 96
Cm
(247) 97
Bk
(247) 98
Cf
(251) 99
Es
(252) 100
Fm
(257) 101
Md
(258) 102
No
(259) 103
Lr
(260) DATA SHEET
CHEM 13 NEWS EXAM 2009
DETACH CAREFULLY
C o n s t a n t s : C o n v e r s i o n f a c t o r s :
NA = 6.022 × 1023 mol−1 1 atm = 101.325 kPa = 760 torr = 760 mm Hg
R = 0.082058 atm L K−1 mol−1 0oC = 273.15 K
= 8.3145 kPa L K−1 mol−1
= 8.3145 J K−1 mol−1
Kw = 1.0×10−14 (at 298 K)
F = 96 485 C mol−1
Equations: PV = nRT k t1/2 = 0.693 pH = pK a + log ( [base] / [acid] ) −± −=24
2bb a cx
a |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2008.pdf | 1 | CHEM 13 NEWS EXAM 2008
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
8 MAY 2008 TIME: 75 MINUTES
This exam is being written by several thousand students. Please be sure that you follow the instructions below.
We'll send you a report on your performance. T op performers are eligible for a prize.
The names of the top 200 students will be published in the September issue of Chem 13 News.
1. Print your name here:
2. Print your school name
and city on your STUDENT
RESPONSE sheet.
3. Select, and enter on the STUDENT RESPONSE sheet, one of the following CODE numbers:
Code 1 Ontario , now studying Grade 12 Chemistry
in a nonsemestered school
Code 2 Ontario , now studying Grade 12 Chemistry
in a semestered school
Code 3 Ontario , Grade 12 Chemistry
already completed
Code 4 Any other Ontario student
Code 5 Manitoba or Saskatchewan high school
student
Code 6 Québec high school student
Code 7 Québec CEGEP student
Code 8 Alberta or British Columbia high school
student
Code 9 New Brunswick, Newfoundland, Nova Scotia,
or Prince Edward Island high school student
Code 10 Northwest Territories, Nunavut, or Yukon
high school student
Code 11 High school student outside Canada
Code 12 Teacher
4. Print
your name (last name, first name and optional
middle initial) on the STUDENT RESPONSE sheet .
Also fill in the corresponding circles below your printed
name.
5. Carefully detach the last page. It is the datasheet.
6. Now answer the exam questions. Questions are not in
order of difficulty. Indicate your choice on the STUDENT RESPONSE sheet by marking one letter beside the question number.
• Mark only one answer for each question. • Questions are all of the same value. • There is a penalty (1/4 off) for each incorrect
answer, but no penalty if you do not answer.
7. Take care that you make firm, black pencil marks, just
filling the oval.
Be careful that any erasures are complete—make the
sheet white again.
Carefully detach the last page.
It is the Data Sheet. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2008.pdf | 2 |
2 /CHEM 13 NEWS EXAM © 2008 UNIVERSITY OF WATERLOO 1 Which of the following statements about the group 17
elements is false ?
A The ionization energy decreases down the group.
*B The group contains both metals and non-metals.
C Electronegativity decreases down the group.
D The melting point increases down the group.
E The most common ion formed by these elements
is X−.
2 Which of the following has the highest melting point?
A I 2(s)
B C 60(s)
C NaCl( s)
*D LiF(s)
E Xe( s)
3 The acid ionization constant for HNO 2 is Ka = 4.5×10−4
at 298 K. What is the pH of 0.100 mol L−1 HNO 2(aq) at
298 K? (Choose the closest value.)
A 1.00
*B 2.17
C 1.67
D 3.23
E 6.53
4 A 0.100 mol L−1 solution of which of the following salts
has the highest pH at 298 K?
A NaF
B NaIO 3
*C NaCN
D NH 4F
E NH 4IO3
5 A solution is prepared by dissolving 4.50 grams of
solid NaOH in 1.00 L of 0.100 mol L
−1 HNO 2(aq) at
298 K? What is the pH of this solution? Assume that
the final volume is 1.00 L.
A 7.00
B 1.90
C 2.45
*D 12.10
E 13.05
6 If 1.00 L of 0.100 mol L
−1 HNO 2(aq) is diluted with water
to a final volume of 4.00 L, then which of the following
statements regarding the new solution is true?
A The percent ionization of the acid decreases and
the pH remains the same.
B The percent ionization of the acid increases and
the pH decreases.
*C The percent ionization of the acid increases and
the pH increases.
D The percent ionization of the acid decreases and
the pH decreases.
E The percent ionization of the acid increases
and the pH remains the same.
7 Which of the following equilibria shifts to the left when
the external pressure is increased and shifts to the
right when the temperature is increased?
A N
2(g) + O 2(g) U 2 NO( g) ΔH > 0
B 2 H 2O(g) U O2(g) + 2 H 2(g) ΔH < 0
C PCl 3(g) + Cl 2(g) U PCl 5(g) ΔH > 0
D N 2(g) + 3 H 2(g) U 2 NH 3(g) ΔH < 0
*E 2 CO 2(g) U 2 CO( g) + O 2(g) ΔH > 0
Ionization constants
(at 298 K)
HIO 3, Ka = 1.7×10−2
HF, Ka = 6.3×10−4
HCN, Ka = 6.2×10−10
NH 3, Kb = 1.8×10−5
H2O, Kw = 1.0×10−14 Ionization constants
(at 298 K)
HNO 2, Ka = 4.5×10−4
H2O, Kw = 1.0×10−14 CHEM 13 NEWS EXAM 2008 - Answers |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2008.pdf | 3 |
© 2008 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 3 Use the table of standard redu ction potentials given below
to answer questions 8 through 10.
Half–Reaction
Eo
Ag+(aq) + e− U Ag(s) +0.80 V
O2(g) + 2H 2O(l) + 4e– U 4 OH–(aq) +0.40 V
Cu2+(aq) + 2e− U Cu(s) +0.34 V
2H+(aq) + 2e− U H2(g) 0.0 V
Sn2+(aq) + 2e− U Sn(s) –0.14 V
Ni2+(aq) + 2e− U Ni(s) –0.25 V
Fe2+(aq) + 2e− U Fe(s) –0.41 V
Cr3+(aq) + 3e− U Cr(s) –0.74 V
Zn2+(aq) + 2e− U Zn(s) –0.76 V
2H2O (l) + 2e− U H2(g) + 2OH−(aq) –0.83 V
Al3+(aq) + 3e− U Al(s) –1.66 V
8 Which of the following is the best reducing agent
under standard conditions?
A Cu( s)
*B Zn( s)
C Al3+(aq)
D Fe2+(aq)
E Ag( s)
9 The metal X dissolves in HCl( aq) but does not react in
pure water, even its powdered form. It is a better
reducing agent than Ni( s). It forms an oxide with the
formula X 2O3. What is X?
A silver, Ag
B copper, Cu
C zinc, Zn
D aluminum, Al
*E chromium, Cr
10 Sacrificial anodes are attached to the hulls of ships to
protect the iron (Fe) in the hull from corrosion. Which of the following metals could be used as a sacrificial
anode for protecting the iron hull of a ship?
A nickel, Ni
*B zinc, Zn
C tin, Sn
D copper, Cu
E silver, Ag
11 The phase diagram for carbon dioxide is shown
below. The temperature and pressure at the triple point (TP) and the critical point (CP) are shown.
Which of the following account s for the fact that liquid
CO
2 is not observed when a piece of solid CO 2 (dry
ice) is placed on a lab bench at 25oC and 1 atm?
A The triple point temperature is less than the
critical point temperature.
B The critical temperature is greater than 25oC.
C The triple point temperature is less than 25oC.
D The critical pressure is greater than 1 atm.
*E The triple point pressure is greater than 1 atm.
12 When 1.50 grams of a compound containing only
carbon, hydrogen, nitrogen and oxygen is burned
completely in excess O 2, 1.72 g CO 2, 0.585 g NO
and 1.23 g H 2O are produced. What is the empirical
formula for the compound?
*A C 2H7O2N
B C 2H14O2N
C CH 7ON
D C 2H7ON 2
E CH 7O2N
13 What is the hybridization of the carbon atoms in
benzene, C 6H6?
A sp2 and sp3
B sp3 only
C sp , sp2 and sp3
*D sp2 only
E sp only
CP
TP
−57oC 31oC5.2 atm72 atm
gas liquid solid |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2008.pdf | 4 |
4 /CHEM 13 NEWS EXAM © 2008 UNIVERSITY OF WATERLOO 14 How many structural isomers are there for C 4H8?
A one
B two
C three
D four
*E more than four
15 The reaction below was studied at 40oC using the
method of initial rates. Data are given in the table
below.
−2
28SO (aq) + 2 I−(aq) → 2 −2
4SO (aq) + I 2(s)
run []−2
28SO
(in mol L-1) []−I
(in mol L-1) Initial Rate
(in mol L−1 s−1)
1 0.010 0.10 3.5×10−4
2 0.020 0.20 1.4×10−3
3 0.020 0.40 2.8×10−3
What are the correct value and units of the rate
constant, k?
A 0.35 mol L−1 s−1
B 3.5 mol L−1 s−1
* C 0.35 mol
−1 L s−1
D 0.35 mol−2 L2 s−1
E 1.8×102 mol−1 L s−1
16 For the reaction below, ΔHo= −879.6 kJ.
3 N 2O(g) + 2 NH 3(g) → 4 N 2(g) + 3 H 2O(g)
Given that ΔHo
f = −45.9 kJ mol−1 for NH 3(g) and
ΔHo
f= −241.8 kJ mol−1 for H 2O(g), what is ΔHo
f
for N 2O(g)?
A 684 kJ mol−1
B −504 kJ mol−1
C −684 kJ mol
−1
* D 82.0 kJ mol−1
E The answer cannot be determined with the
information provided.
17 The following figure shows the contents and
pressures of three vessels of gas which are joined by a connecting tube.
After the valves on the vessels are opened, the final
pressure is measured and found to be 0.675 atm.
What is the total volume of the connecting tube? All
vessels are at a constant temperature of 25ºC.
A 0.53 L
* B 0.056 L
C 0.094 L
D 0.040 L
E 0.023 L
18 At a certain temperature, the equilibrium constant for
the reaction below is
Kp = 0.100.
P4(g) U 2 P 2(g)
In an experiment, some P 4 gas was added to an
empty reaction vessel and then the vessel was
quickly sealed. The total pr essure at equilibrium was
1.00 atm. What was the initial pressure of P 4 used in
this experiment?
A 1.00 atm
B 0.730 atm
C 0.752 atm
* D 0.865 atm
E 0.667 atm
valve
He
0.75 atm
1.0 L Xe
0.45 atm
2.5 L Ar
1.20 atm
1.0 L |
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© 2008 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 5 19 In acidic aqueous solution, zinc metal is oxidized to
Zn2+. The net ionic equation for the reaction is given
below.
Zn(s) + 2 H+(aq) → Zn2+(aq) + H 2(g)
In an experiment, 5.0 grams of Zn( s) were added to
100 mL of 1.0 mol L−1 HCl( aq). Which of the following
changes to the procedure would not affect the initial
rate of the reaction?
A warming the HCl solution before adding the zinc
B using zinc powder instead of zinc granules
* C using 50 mL of 1.0 mol L
−1 HCl( aq)
D using 200 mL of 0.50 mol L−1 HCl( aq)
E using 100 mL of 1.0 mol L−1 H2SO 4(aq)
20 Which of the following groups of ions and atoms is
comprised of species having exactly the same ground
state electron configuration?
A Al
3+, O2−, Ne, Cl−
B Ca, Ti2+, Cl−, S2−
C H−, He, Li, Be2+
D Ne, Ar, Kr, Xe
*E Ca2+, Ti4+, Cl−, S2−
21 Proteins are polymers of which kind of acids?
* A amino acids
B strong acids
C binary acids
D inorganic acids
E lactic acids
22 In separate experiments, a 50.0-mL sample of each
of the two solutions listed below is titrated with 0.10 mol L
−1 NaOH( aq).
0.10 mol L−1 HCl( aq), pH = 1.0
0.10 mol L−1 HCN( aq), pH = 5.1
Which of the following statements is true?
A For both titrations, the pH at the equivalence
point is 7.00.
B It takes a greater volume of the NaOH solution to
reach the equivalence point for the titration of the
HCl solution than it does for the titration of the
HCN solution.
C For both titrations, the pH at the equivalence
point is greater than 7.00.
D HCN is a stronger acid than HCl.
*E For both titrations, it takes 50.0 mL of the NaOH
solution to reach the equivalence point.
23 At high temperatures, sodium hydrogen carbonate,
NaHCO 3, decomposes according to the chemical
equation given below.
2 NaHCO 3(s) U Na 2CO 3(s) + H 2O(g) + CO 2(g)
What is the equilibrium co nstant expression for this
reaction?
A [] [ ] [ ]
[]=cK22 2 3
3H O CO Na CO
NaHCO
B [] [ ] [ ]
[]=cK22 2 3
2
3H O CO Na CO
NaHCO
*C [] [ ]=cK22HO C O
D []
[] [ ] [ ]=cK2
3
22 2 3NaHCO
H O CO Na CO
E [] [ ]=cK
221
HO C O
|
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6 /CHEM 13 NEWS EXAM © 2008 UNIVERSITY OF WATERLOO 24 Which of the following statements is always true?
A A nonelectrolyte is ionized completely in aqueous
solution.
B Most ionic compounds of the Group 1 elements
are insoluble.
C A 1 mol L−1 solution of NH 3(aq) is a better
conductor of electric current than a 1 mol L−1
solution of HCl( aq).
*D A weak acid is partially ionized in aqueous
solution.
E Cl− will precipitate Na+ from solution.
25
Given the data below, what is the bond dissociation
energy for the H-Cl bond?
*
A 430 kJ mol−1
B 384 kJ mol−1
C 123 kJ mol−1
D 92 kJ mol−1
E 767 kJ mol−1
26 Of the following organic compounds, which is least
soluble in water at 298 K?
A methanol, CH 3OH
B ethanol, CH 3CH 2OH
* C dimethyl ether, H 3COCH 3
D ethylene glycol, HOCH 2CH 2OH
E ethanoic acid, CH 3COOH
27 The temperature-time graph is shown below for
heating H 2O at a constant rate of 1.00 kJ s−1. What
does the line segment DE represent?
A warming of ice
B fusion
C warming of liquid
*D vaporization
E condensation
28 The unbalanced chemical equation for the oxidation
of −Br by −
4MnO is given below. The reaction occurs
in aqueous acidic solution.
−Br + −
4MnO → Br2 + Mn2+
How many moles of −
4MnO are required to oxidize
exactly 1.0 mol −Br?
A 1.0 mol
* B 0.2 mol
C 5.0 mol
D 0.1 mol
E 10 mol
29 Which of the following is the best choice to measure
accurately 22.5 mL of a solution?
*A a 50 mL buret
B a 50 mL Erlenmeyer flask
C a 50 mL beaker
D a 50 mL graduated cylinder
E a 50 mL volumetric pipet H-H bond dissociation energy = 432 kJ mol−1
Cl-Cl bond dissociation energy = 244 kJ mol−1
ΔfHofor HCl = −92 kJ mol−1 AB
C D E
time temperature |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2008.pdf | 7 |
© 2008 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 7 30 Solid NH 4NO 3 is added to a solution of sodium
hydroxide, NaOH, and the solution is warmed. Which of the following gases is produced?
A nitrogen, N 2
B oxygen, O 2
C dinitrogen oxide, N 2O
D hydrogen, H 2
*E ammonia, NH 3
31 Which one of the following solutions does not conduct
electricity at 25oC?
*A 0.10 mol L−1 CH 3CH 2OH(aq)
B 0.10 mol L−1 H2SO 4(aq)
C 0.10 mol L−1 CH 3COOH( aq)
D 0.10 mol L−1 HNO 3(aq)
E 0.10 mol L−1 NH 3(aq)
32 In which of the following compounds is the oxidation
state of chlorine equal to +5?
A HCl
B ClF 3
* C HClO 3
D PCl 5
E HClO 2
33 The structure of which of the following is not a hybrid
of two or more equivalent resonance structures?
A −2
3CO
B −3
4PO
C C6H6
D O 3
* E C 2H4
34 For the reaction
2 HBr + ½ O 2 → H 2O + Br 2,
the following mechanism has been proposed. HBr + O
2 → HOOBr fast
HOOBr + HBr → 2 HOBr slow
HOBr + HBr → H 2O + Br 2 fast
What is the predicted rate law for the overall reaction?
* A Rate = k [HBr]2 [O2]
B Rate = k [HBr]2 [O2]1/2
C Rate = k [HBr] [O 2]
D Rate = k [HBr] [O 2]2
E Rate = k
21 / 2
222[H O][Br ]
[HBr] [O ]
35
Which of the following substances is the most soluble
in hexane, C 6H14(l)?
A NaCl
* B Cl2
C CH 3Cl
D HCl
E CaCl 2
36 Which oxide of nitrogen is 36.8% N by mass?
A N2O4
B NO
* C N2O3
D NO 2
E N 2O
|
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2008.pdf | 8 |
8 /CHEM 13 NEWS EXAM © 2008 UNIVERSITY OF WATERLOO 37 A student drew the following Lewis structures for NO,
CO, NH 3 and BH 3. Which of the following structures
is (are) correct?
( 1 ) ( 2 )
( 3 ) ( 4 )
A (1) only
B (3) and (4)
*
C (1) and (2)
D (2) and (3)
E (3) only
38 The reaction N 2(g) + 3 H 2(g) U 2 NH 3(g) is
exothermic. The reaction is allowed to reach
equilibrium in a closed vessel. Which of the following
will lead to an increase in the number of moles of ammonia in the equilibrium mixture?
(1) increasing the temperature
(2) adding a catalyst (3) increasing the external pressure
(4) adding N
2 to the reaction vessel
A (1) only
B (1) and (2) only
C (2) and (3) only
* D (3) and (4) only
E (1), (2) and (4)
39 What is the maximum mass of nickel metal that can be deposited from an aqueous solution of Ni(NO
3)2
by the passage of three moles of electrons?
A 29 g
B 39 g
C 59 g
* D 88 g
E 176 g
40 Ethanoic acid, CH 3COOH, is a weak acid in water.
What happens when 0.01 moles of HCl are added to
a 0.1 mol L−1 solution of ethanoic acid?
A The pH of the solution increases and the percent ionization of ethanoic acid increases.
B The pH of the solution decreases and the percent
ionization of ethanoic acid increases.
*C The pH of the solution decreases and the percent
ionization of ethanoic acid decreases.
D The pH of the solution increases and the percent
ionization of ethanoic acid decreases.
E The weak acid is neutralized by the strong acid
and the pH of the solution is 7.00.
NH
HHBH H
HNO CO |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2008.pdf | 9 |
© 2008 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 9
1
1A
18
8A
1
H
1.008
2
2A
13
3A
14
4A
15
5A
16
6A
17
7A 2
He
4.003
3
Li
6.941 4
Be
9.012 5
B
10.816
C
12.01 7
N
14.01 8
O
16.009
F
19.0010
Ne
20.18
11
Na
22.99 12
Mg
24.31
3
3B
4
4B
5
5B
6
6B
7
7B
8
←
9
8B
10
→
11
1B
12
2B 13
Al
26.9814
Si
28.09 15
P
30.97 16
S
32.0717
Cl
35.4518
Ar
39.95
19
K
39.10 20
Ca
40.08 21
Sc
44.96 22
Ti
47.88 23
V
50.94 24
Cr
52.00 25
Mn
54.9426
Fe
55.8527
Co
58.9328
Ni
58.6929
Cu
63.5530
Zn
65.3831
Ga
69.7232
Ge
72.59 33
As
74.92 34
Se
78.9635
Br
79.9036
Kr
83.80
37
Rb
85.47 38
Sr
87.62 39
Y
88.91 40
Zr
91.22 41
Nb
92.91 42
Mo
95.94 43
Tc
(98) 44
Ru
101.145
Rh
102.946
Pd
106.447
Ag
107.948
Cd
112.449
In
114.850
Sn
118.7 51
Sb
121.8 52
Te
127.653
I
126.954
Xe
131.3
55
Cs
132.9 56
Ba
137.3 57
La
138.9 72
Hf
178.5 73
Ta
180.9 74
W
183.9 75
Re
186.276
Os
190.277
Ir
192.278
Pt
195.179
Au
197.080
Hg
200.681
Tl
204.482
Pb
207.2 83
Bi
209.0 84
Po
(209) 85
At
(210) 86
Rn
(222)
87
Fr
(223) 88
Ra
226 89
Ac
227.0 104
Rf 105
Db 106
Sg 107
Bh 108
Hs 109
Mt 110
Uun 111
Uuu 112
Uub 113
Uut
58
Ce
140.1 59
Pr
140.9 60
Nd
144.2 61
Pm
(145) 62
Sm
150.463
Eu
152.0064
Gd
157.365
Tb
158.966
Dy
162.567
Ho
164.968
Er
167.3 69
Tm
168.9 70
Yb
173.071
Lu
175.0
90
Th
232.0 91
Pa
231.0 92
U
238.0 93
Np
237.094
Pu
(244) 95
Am
(243) 96
Cm
(247) 97
Bk
(247) 98
Cf
(251) 99
Es
(252) 100
Fm
(257) 101
Md
(258) 102
No
(259) 103
Lr
(260) DATA SHEET
CHEM 13 NEWS EXAM 2008
DETACH CAREFULLY
C o n s t a n t s : C o n v e r s i o n f a c t o r s :
NA = 6.022 × 1023 mol−1 1 atm = 101.325 kPa = 760 torr = 760 mm Hg
R = 0.082058 atm L K−1 mol−1 0oC = 273.15 K
= 8.3145 kPa L K−1 mol−1
= 8.3145 J K−1 mol−1
Kw = 1.0×10−14 (at 298 K)
F = 96 485 C mol−1
Equations: PV = nRT k t1/2 = 0.693 pH = pK a + log ( [base] / [acid] ) −± −=24
2bb a cx
a |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2007.pdf | 1 | CHEM 13 NEWS EXAM 2007
UNIVERSITY OF WATERLOO
DEPARTMENT OF CHEMISTRY
10 MAY 2007 TIME: 75 MINUTES
This exam is being written by several thousand students. Please be sure that you follow the instructions below.
We'll send you a report on your performance. Top performers are eligible for a prize.
1. Print your name here:
2. Print your school name
and city on your STUDENT
RESPONSE sheet.
3. Select, and enter on the STUDENT RESPONSE sheet, one of the following CODE numbers:
Code 1 Ontario , now studying Grade 12 Chemistry
in a nonsemestered school
Code 2 Ontario , now studying Grade 12 Chemistry
in a semestered school
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already completed
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student
Code 6 Québec high school student
Code 7 Québec CEGEP student
Code 8 Alberta or British Columbia high school
student
Code 9 New Brunswick, Newfoundland, Nova Scotia,
or Prince Edward Island high school student
Code 10 Northwest Territories, Nunavut, or Yukon
high school student
Code 11 High school student outside Canada
Code 12 Teacher
4. Print
your name (last name, first name and optional
middle initial) on the STUDENT RESPONSE sheet .
Also fill in the corresponding circles below your printed
name.
5. Carefully detach the last page. It is the datasheet.
6. Now answer the exam questions. Questions are not in
order of difficulty. Indicate your choice on the STUDENT RESPONSE sheet by marking one letter beside the question number.
• Mark only one answer for each question. • Questions are all of the same value. • There is a penalty (1/4 off) for each incorrect
answer, but no penalty if you do not answer.
7. Take care that you make firm, black pencil marks, just
filling the oval.
Be careful that any erasures are complete—make the
sheet white again.
Carefully detach the last page.
It is the Data Sheet. |
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2 / CHEM 13 NEWS EXAM © 2007 UNIVERSITY OF WATERLOO 1 In which of the following series are the atomic orbitals
given in order of increasing energy?
A 3d, 4s, 4p, 4d, 4f, 5s
B 2s, 3s, 2p, 3p, 3d, 4s
C 4s, 3d, 4p, 4d, 4f, 5s
*D 4s, 3d, 4p, 5s, 4d, 5p
E 1s, 2s, 3s, 4s, 2p, 3p
2 What is the ground state electron configuration of Ar?
*A 1s2 2s2 2p6 3s2 3p6
B 1s2 2s2 2p6
C 1s2 2s2 3s2 3p6
D 1s2 2s2 2p3 3s2 3p3
E 1s2 1p6 2s2 2p6 3s2 3p6
3 Which of the following ions, in its ground electronic
state, does not
have the same electronic
configuration as a ground state Ar atom?
A P3−
B Cl−
C K+
D Ca2+
*E Sc2+
4 Which of the following molecules is linear?
A H 2O
B O 3
C NH 3
*D HCN
E HONO
5 Which of the following molecules has polar bonds but
is nonpolar?
A N
2H4
*B CCl
4
C HNO 3
D CH 2Cl2
E F 2O
6 Why is the boiling point of iodine chloride (I-Cl)
greater than that of bromine (Br 2)?
A ICl is heavier than Br 2.
B ICl is a covalent compound and Br 2 is not.
C The I-Cl bond is stronger than the Br −Br bond.
*D ICl is a polar molecule and Br 2 is nonpolar.
E ICl is an ionic compound and Br 2 is not.
7 What is the molecular geometry of phosphorus
pentachloride, PCl
5 ?
A square pyramidal
*B trigonal bipyramidal
C pentagonal
D trigonal pyramidal
E octahedral
8 Which of the following correctly characterizes the
bonds and geometry of C
2H4?
A four σ bonds, one π bond and an H-C-C bond
angle very close to 109o
B five σ bonds, no π bonds and an H-C-C bond
angle very close to 90o
* C five σ bonds, one π bond and an H-C-C bond
angle very close to 120o
D three σ bonds, two π bonds and an H-C-C bond
angle very close to 109o
E four σ bonds, two π bonds and an H-C-C bond
angle very close to 120o
CHEM 13 NEWS EXAM 2007 - Answers |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2007.pdf | 3 |
© 2007 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 3
9 What is the oxidation state of rhenium (Re) in ReO
4−?
A 0
B +1
C +3
D +4
*E +7
10 What is the coefficient of zinc (Zn) when the equation
above for the reaction is balanced using the smallest
whole number coefficients?
A 1
B 2
*C 7
D 16
E none of the above
11 For the reaction above, what element or ion is the
reducing agent?
A Re( s)
*B Zn( s)
C ReO
4−(aq)
D Zn2+(aq)
E H+(aq)
12 In the galvanic cell shown below, what is the reaction
that occurs at the cathode?
A H
2(g) → 2H+(aq) + 2e−
B 2H+(aq) + 2e− → H2(g)
C Cu( s) → Cu2+(aq) + 2e−
*D Cu2+(aq) + 2e− → Cu(s)
E Pt( s) + H 2(g) + 4Cl−(aq)
→ PtCl 42−(aq) + 2H+(aq) + 4e−
13 In the statements below, X refers to one of Ca, Fe, Pb,
Cu or Pt. What is the identity of X?
• X( s) reacts spontaneously in 1 mol L
−1 HCl( aq) to
give XCl 2(aq) and H 2(g).
• The reaction 3X2+(aq) + 2Al( s) → 3X(s) + 2Al3+(aq)
is spontaneous under standard conditions.
• X( s) is a better reducing agent than Co( s) under
standard conditions.
A Ca
*B Fe
C Pb
D Cu
E Pt
Use the following information to
answer questions 9-11.
In acidic solution, zinc metal reacts spontaneously with
ReO 4−. The unbalanced chemical equation for the
reaction is given below.
Zn(s) + ReO 4−(aq) + H+(aq) → Re(s) + Zn2+(aq) + H 2O(l)
Half-reaction Eo
Ca2+(aq) + 2e− → Ca(s) −2.84 V
Al3+(aq) + 3e− → Al(s) −1.66 V
Fe2+(aq) + 2e− → Fe(s) −0.44 V
Co2+(aq) + 2e− → Co(s) −0.28 V
Pb2+(aq) + 2e− → Pb(s) −0.13 V
2H+(aq) + 2e− → H2(g) 0.00 V
Cu2+(aq) + 2e− → Cu(s) 0.34 V
Pt2+(aq) + 2e− → Pt(s) 1.18 VHCl(aq)
1 mol L−1 H2(g)
1 atm
Pt(s)Cu(s)
Cu(NO 3)2(aq)
1 mol L−1 salt bridge 0.34 V
e−e− |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2007.pdf | 4 |
4 / CHEM 13 NEWS EXAM © 2007 UNIVERSITY OF WATERLOO 14 In the laboratory, one must never dip a stirring rod
into a reagent bottle. This is because
A the bottle may tip over
B the stirring rod might break
C the rod might puncture the bottle
* D the contents of the bottle may become
contaminated
E reagent can creep up the rod and come in contact
with one’s hand
15 What is the most accurate and precise way to
measure one litre of water?
A Use a 1-L graduated cylinder.
*B Use a 1-L volumetric flask.
C Use a 100-mL volumetric flask ten times.
D Use a 100-mL pipette ten times.
E Weigh 1 kg of water using a balance that weighs
to ±1 g.
16 Examine the diagrams below carefully. Which of the
burets shown below is/are ready for use?
(1) (2) (3) (4)
A (1) only
B (2) only
C (3) only
* D (4) only
E (1), (3) and (4)
17 An aqueous solution is 5.0% ethanoic acid (HC 2H3O2)
by mass and its density is 0.96 g mL−1. What is the
molar concentration of ethanoic acid in this solution?
* A 0.80 mol L−1
B 4.8 mol L−1
C 12 mol L−1
D 0.087 mol L−1
E 16 mol L−1
18 Which reagents react to give ethyl benzoate
(C
6H5COOC 2H5) and water? The structure of ethyl
benzoate is given below.
A and
* B and CH
3CH 2OH
C and C
6H5CH 2OH
D CH 3CH 2OH and C 6H5OH
E none of the above
19 Which of the following is not
a pair of isomers?
A ethyl benzene (C 6H5-C2H5) and
dimethyl benzene, C 6H4(CH 3)2
B 1-propanol (CH 3CH 2CH 2OH) and
2-propanol (CH 3CHOHCH 3)
C ethanol (C 2H5OH) and dimethyl ether (CH 3OCH 3)
* D 2-butanone (CH 3COCH 2CH 3) and
1-butanol (CH 3CH 2CH 2CH 2OH)
E urea (NH 2CONH 2) and ammonium cyanate
(NH 4CNO)
5049482 1 0
5049482 1 0
5049482 1 0
5049482 1 0 HC 2H3O2, 60.05 g mol−1
H3CCO
OH C6H5CO
OH
C6H5CO
OH
H3CCO
OHC6H5CO
OC H 2CH3 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2007.pdf | 5 |
© 2007 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 5 20 What is the IUPAC name for the compound below?
A 2-chloro-1,4-dimethylpentane
B 3-chloro-1,1,4-trimethylbutane
*C 4-chloro-2-methylhexane
D 3-chloro-5-methylhexane
E 3-chloroheptane
21 Which of the following compounds is a solid at room
temperature?
A H-C≡C-H
B CH 3CH 2CH 3
C CH 3CH 2CH 2OH
D C 8H18
*E C 6H5OH
22 How many different structural isomers are there for the
compound chlorobutane (C
4H9Cl)?
A two
B three
* C four
D five
E more than five
23 According to the reaction profile below, what is ΔH for
the reaction 4HBr( g) + O
2(g) → 2H 2O(g) + 2Br 2(g)?
A 276 kJ
* B −276 kJ
C 434 kJ
D −434 kJ
E 158 kJ
24 The enthalpy change for the reaction below is
ΔH = −58 kJ (per mole of N
2O4 formed).
2 N O 2(g)
−⎯⎯⎯→←⎯⎯⎯1
1k
k N 2O4(g)
If k1 and k−1 are the rate constants for the forward and
reverse reactions, respectively, and Kc is the
equilibrium constant for the reaction as written, then what is the effect of adding a catalyst on the values of
k
1, k−1 and Kc?
A k1 increases, k−1 increases, Kc increases
B k1 decreases, k−1 decreases, Kc decreases
*C k1 increases, k−1 increases, Kc remains the same
D k1 decreases, k−1 decreases, Kc remains the same
E k1 remains the same, k−1 remains the same,
Kc remains the same
158 kJ
434 kJ
Reaction progress Potential
Energy
4HBr( g) + O 2(g)
2H2O(g) + 2Br 2(g) HCH
HCCHH
CCCC
H
H ClH
HHH
HH
H H
For 20, D is not correct because you must number the C atoms so that the
substituents have the lowest numbers possible (4+2 is less than 3+5). |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2007.pdf | 6 |
6 / CHEM 13 NEWS EXAM © 2007 UNIVERSITY OF WATERLOO 25 The reaction below reaches equilibrium in a closed
reaction vessel.
CaCO 3(s) U CaO( s) + CO 2(g), ΔH = 178 kJ
Which of the following actions cause(s) an increase in
the partial pressure of CO 2(g)?
(i) increasing the temperature (ii) adding some CaCO
3(s)
(iii) increasing the volume of the reaction vessel
*A (i) only
B (i) and (ii)
C (i), (ii) and (iii)
D (ii) only
E (i) and (iii)
26 The reaction below was studied using the method of
initial rates.
−
3BrO (aq) + 5Br−(aq) + 6H+(aq) → 3Br 2(aq) + 3H 2O(l)
The rate law for the reaction was determined to be
Rate = k [−
3BrO ] [Br − ] [H+ ]2, where Rate refers to the
rate of consumption of−
3BrO . Which of the following
statements is false ?
* A If concentrations are measured in mol L−1 and
time is measured in seconds ( s), then the units of
k are mol L−1 s−1.
B The rate of consumption of Br − is five times
greater than the rate of consumption of −
3BrO .
C The conversion of reactants into products must
involve two or more simpler reactions.
D If the concentrations of all reactants are doubled,
the rate of consumption of−
3BrO will increase by a
factor of sixteen.
E When the reaction reaches a state of dynamic
equilibrium, [−
3BrO ] stops changing.
27
Which of the following reagents could be used to
separate the metal ions in an aqueous mixture of Fe(NO
3)3 and AgNO 3?
A NH 3
B KOH
*C NaCl
D
HNO 3
E
CaCO 3
28 The reaction below was studied using the method of
initial rates.
2 HgCl 2(aq) + C 2O42−(aq) → products
The following data were recorded. ( Rate refers to the
initial rate of consumption of C 2O42−.)
ExperimentInitial [HgCl 2]
(in mol L-1) Initial [C 2O42−]
(in mol L-1) Rate
(in mol L-1 hr-1)
1 0.0836 0.202 0.260
2 0.0836 0.404 1.04
3 0.0334 0.404 0.416
What is the rate law for the reaction?
*A Rate = k [HgCl 2] [C2O42− ]2
B Rate = k [HgCl 2]2
[C2O42− ]
C Rate = k [HgCl 2] [C2O42− ]
D Rate = k [HgCl 2]2
[C2O42− ]2
E Rate = k [HgCl 2]½
[C2O42− ]
29
A concentrated solution of ethanoic acid (HC 2H3O2)
has a concentration of 17.4 mol L−1. What volume of
this solution is needed to prepare 0.25 L of
0.30 mol L−1 HC 2H3O2(aq)?
A 4.7 mL
*B 4.3 mL
C 3.0 mL
D 2.5 mL
E 2.2 mL
|
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2007.pdf | 7 |
© 2007 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 7 30 Which of the following is a valid set of quantum
numbers for an electron in a p orbital?
A n = 1, l = 1, ml = 0, ms = ½
B n = 3, l = 1, ml = 2, ms = ½
* C n = 2, l = 1, ml = −1, ms = ½
D n = 2, l = 0, ml = 0, ms = ½
E n = 2, l = 2, ml = 0, ms = ½
31 For the reaction below, ΔHo = −518.02 kJ per mole of
H2S. What is ΔHo
f for H 2S(g)?
H 2S(g) + 3
2 O2(g) → SO 2(g) + H 2O(g)
*A −20.63 kJ mol−1
B 41.26 kJ mol−1
C 20.63 kJ mol−1
D −497.39 kJ mol−1
E −41.26 kJ mol−1
32 What is the pH of 0.10 mol L−1 HClO 2(aq)?
A 1.98
B 5.11
* C 1.55
D 2.52
E 1.00
33 Consider the reaction below.
2 SO 2(g) + O 2(g) U 2 SO 3(g)
In an experiment, 0.10 mol of O 2 and 0.10 mol of SO 3
are added to an empty 1.0-L flask and then the flask
is sealed. Which of the following must be true at
equilibrium?
A [SO 2] = [O 2] = [SO 3]
B [O2] < [SO 3]
C [O2] = 2 [SO 2]
D [O 2] = [SO 2]
* E [SO 3] < [O 2] 34 Which of the following statements concerning the
structure below is true?
A There are eight σ bonds in this structure.
B The nitrogen atom is sp-hybridized.
C The H-C-H bond angle is 90o.
D The structure above is the most important
structure for the CH 3NCO molecule.
*
E None of the statements above are true.
35 When a 10.0-g sample of a mixture of CH 4 and C 2H6
is burned excess oxygen, exactly 525 kJ of heat is
produced. What is the percentage by mass of CH 4 in
the original mixture?
CH 4(g) + 2 O2(g) → CO 2(g) + 2 H2O(l)
∆H = −890.4 kJ (per mol CH 4)
C2H6(g) + 7
2 O2(g) → 2 CO 2(g) + 3 H2O(l)
∆H = −1560.0 kJ (per mol C 2H6)
* A 17%
B 21%
C 34%
D 59%
E 87%
36 Which of the following is an acceptable Lewis
structure for the thiocyanate ion, SCN− ?
A
B
C
*D
E ΔHo
f
(in kJ mol−1)
SO 2(g) −296.83
H2O(g) −241.82
Ka = 1.1×10−2 for HClO 2 CH
H
HNC O
CH 4, 16.042 g mol−1
C2H6, 30.068 g mol−1
SCN
SCN
SCNSCN
SCNThe reaction must
go ← to establish
equilibrium. |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2007.pdf | 8 |
8 / CHEM 13 NEWS EXAM © 2007 UNIVERSITY OF WATERLOO 37 What is the pressure (in mmHg) of the gas inside the
apparatus below if P atm = 750 mmHg, Δh1 = 20 mm
and Δh2 = 50 mm?
A 20 mmHg
B 50 mmHg
C 700 mmHg
* D 730 mmHg
E 770 mmHg
38 Consider the compounds HF, HCl, HBr and HI. Of
these compounds, which one has the highest boiling
point and which one is the strongest acid in water?
A HF has the highest boiling point and is the
strongest acid
B HI has the highest boiling point and is the
strongest acid
*
C HF has the highest boiling point and HI is the
strongest acid
D HI has the highest boiling point and HF is the
strongest acid
E HI has the highest boiling point and HCl is the
strongest acid
39 Ethanoic acid, CH 3COOH, is a weak acid in water.
Which substance, when added to an aqueous
solution of ethanoic acid, causes both the pH and the percentage ionization of CH
3COOH to decrease ?
A NaCH 3COO
B NaCl
*
C CH 3COOH
D NaNO 3
E AgCl
40 A compound of carbon, hydrogen and oxygen is found
to be 52.13% carbon by mass, 13.13% hydrogen by mass, and 34.74% oxygen by mass. What is the simplest formula of the compound?
A C5H8O
B C3H4O3
* C C2H6O
D CH 2O2
E CHO
Δh1
Gas Patm
mercury (Hg) Δh2 H, 1.008 g mol−1
C, 12.01 g mol−1
O, 16.00 g mol−1 |
https://uwaterloo.ca/chemistry/sites/default/files/uploads/documents/chem-13-news-exam-solution-2007.pdf | 9 |
© 2007 UNIVERSITY OF WATERLOO CHEM 13 NEWS EXAM / 9
1
1A
18
8A
1
H
1.008
2
2A
13
3A
14
4A
15
5A
16
6A
17
7A 2
He
4.003
3
Li
6.941 4
Be
9.012 5
B
10.816
C
12.01 7
N
14.01 8
O
16.009
F
19.0010
Ne
20.18
11
Na
22.99 12
Mg
24.31
3
3B
4
4B
5
5B
6
6B
7
7B
8
←
9
8B
10
→
11
1B
12
2B 13
Al
26.9814
Si
28.09 15
P
30.97 16
S
32.0717
Cl
35.4518
Ar
39.95
19
K
39.10 20
Ca
40.08 21
Sc
44.96 22
Ti
47.88 23
V
50.94 24
Cr
52.00 25
Mn
54.9426
Fe
55.8527
Co
58.9328
Ni
58.6929
Cu
63.5530
Zn
65.3831
Ga
69.7232
Ge
72.59 33
As
74.92 34
Se
78.9635
Br
79.9036
Kr
83.80
37
Rb
85.47 38
Sr
87.62 39
Y
88.91 40
Zr
91.22 41
Nb
92.91 42
Mo
95.94 43
Tc
(98) 44
Ru
101.145
Rh
102.946
Pd
106.447
Ag
107.948
Cd
112.449
In
114.850
Sn
118.7 51
Sb
121.8 52
Te
127.653
I
126.954
Xe
131.3
55
Cs
132.9 56
Ba
137.3 57
La
138.9 72
Hf
178.5 73
Ta
180.9 74
W
183.9 75
Re
186.276
Os
190.277
Ir
192.278
Pt
195.179
Au
197.080
Hg
200.681
Tl
204.482
Pb
207.2 83
Bi
209.0 84
Po
(209) 85
At
(210) 86
Rn
(222)
87
Fr
(223) 88
Ra
226 89
Ac
227.0 104
Rf 105
Db 106
Sg 107
Bh 108
Hs 109
Mt 110
Uun 111
Uuu 112
Uub 113
Uut
58
Ce
140.1 59
Pr
140.9 60
Nd
144.2 61
Pm
(145) 62
Sm
150.463
Eu
152.0064
Gd
157.365
Tb
158.966
Dy
162.567
Ho
164.968
Er
167.3 69
Tm
168.9 70
Yb
173.071
Lu
175.0
90
Th
232.0 91
Pa
231.0 92
U
238.0 93
Np
237.094
Pu
(244) 95
Am
(243) 96
Cm
(247) 97
Bk
(247) 98
Cf
(251) 99
Es
(252) 100
Fm
(257) 101
Md
(258) 102
No
(259) 103
Lr
(260) DATA SHEET
CHEM 13 NEWS EXAM 2006
DETACH CAREFULLY
C o n s t a n t s : C o n v e r s i o n f a c t o r s :
NA = 6.022 × 1023 mol−1 1 atm = 101.325 kPa = 760 torr = 760 mm Hg
R = 0.082058 atm L K−1 mol−1 0oC = 273.15 K
= 8.3145 kPa L K−1 mol−1
= 8.3145 J K−1 mol−1
Kw = 1.0×10−14 (at 298 K)
F = 96 485 C mol−1
Equations: PV = nRT k t1/2 = 0.693 pH = pK a + log ( [base] / [acid] ) −± −=24
2bb a cx
a |
https://www.press.muni.cz/media/3019066/answers_to_all_questions.pdf | 1 | WC -1
Answers to All
Questions and Problems
Chapter 1
1.1 In a few sentences, what were Mendel’s key ideas about
inheritance?
ANS: Mendel postulated transmissible factors—genes—to
explain the inheritance of traits. He discovered that
genes exist in different forms, which we now call alleles.
Each organism carries two copies of each gene. During
reproduction, one of the gene copies is randomly incor-
porated into each gamete. When the male and female
gametes unite at fertilization, the gene copy number is
restored to two. Different alleles may coexist in an organ-
ism. During the production of gametes, they separate
from each other without having been altered by
coexistence.
1.2 Both DNA and RNA are composed of nucleotides. What
molecules combine to form a nucleotide?
ANS: Each nucleotide consists of a sugar, a nitrogen-containing
base, and a phosphate.
1.3 Which bases are present in DNA? Which bases are pres-
ent in RNA? Which sugars are present in each of these
nucleic acids?
ANS: The bases present in DNA are adenine, thymine, gua-
nine, and cytosine; the bases present in RNA are adenine,
uracil, guanine, and cytosine. The sugar in DNA is
deoxyribose; the sugar in RNA is ribose.
1.4 What is a genome?
ANS: A genome is the set of all the DNA molecules that are
characteristic of an organism. Each DNA molecule
forms one chromosome in a cell of the organism.
1.5 The sequence of a strand of DNA is ATTGCCGTC. If
this strand serves as the template for DNA synthesis,
what will be the sequence of the newly synthesized
strand?
ANS: TAACGGCAG
1.6 A gene contains 141 codons. How many nucleotides are
present in the gene’s coding sequence? How many amino
acids are expected to be present in the polypeptide
encoded by this gene?ANS: There are 3 × 141 = 423 nucleotides in the gene’s cod-
ing sequence. Its polypeptide product will contain 141
amino acids.
1.7 The template strand of a gene being transcribed is CTT-
GCCAGT. What will be the sequence of the RNA made
from this template?
ANS: GAACGGUCT
1.8 What is the difference between transcription and
translation?
ANS: T ranscription is the production of an RNA chain using a
DNA chain as a template. T ranslation is the production
of a chain of amino acids—that is, a polypeptide—using
an RNA chain as a template.
1.9 RNA is synthesized using DNA as a template. Is DNA
ever synthesized using RNA as a template? Explain.
ANS: Sometimes, DNA is synthesized from RNA in a process
called reverse transcription. This process plays an impor-
tant role in the life cycles of some viruses.
1.10 The gene for a-globin is present in all vertebrate species.
Over millions of years, the DNA sequence of this gene
has changed in the lineage of each species. Consequently,
the amino acid sequence of a-globin has also changed in
these lineages. Among the 141 amino acid positions in
this polypeptide, human a-globin differs from shark
a-globin in 79 positions; it differs from carp a-globin in
68 and from cow a-globin in 17. Do these data suggest
an evolutionary phylogeny for these vertebrate species?
ANS: The human and cow a-globins are least different; there-
fore, on the assumption that differences in a-globin
refl ect the degree of phylogenetic relationship, the
human and the cow are the most closely related organ-
isms among those mentioned. The next closest “relative”
of humans is the carp, and the most distant relative is the
shark.
1.11 Sickle-cell anemia is caused by a mutation in one of the
codons in the gene for b-globin; because of this mutation,
the sixth amino acid in the b-globin polypeptide is a
valine instead of a glutamic acid. A less severe type of ane-
mia is caused by a mutation that changes this same codon
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to one specifying lysine as the sixth amino acid in the
b-globin polypeptide. What word is used to describe the
two mutant forms of this gene? Do you think that an indi -
vidual carrying these two mutant forms of the b-globin
gene would suffer from anemia? Explain.
ANS: The two mutant forms of the b-globin gene are properly
described as alleles. Because neither of the mutant alleles
can specify a “normal” polypeptide, an individual who
carries each of them would probably suffer from
anemia.
1.12 Hemophilia is an inherited disorder in which the blood-
clotting mechanism is defective. Because of this defect,
people with hemophilia may die from cuts or bruises,
especially if internal organs such as the liver, lungs, or
kidneys have been damaged. One method of treatment
involves injecting a blood-clotting factor that has been
purified from blood donations. This factor is a protein
encoded by a human gene. Suggest a way in which mod -
ern genetic technology could be used to produce this
factor on an industrial scale. Is there a way in which the
inborn error of hemophilia could be corrected by human
gene therapy?
ANS: The gene for the human clotting factor could be isolated
from the human genome and transferred into bacteria,
which could then be grown in vats to produce large
amounts of the gene’s protein product. This product could
be isolated from the bacteria, purified, and then injected
into patients to treat hemophilia. Another approach would
be to transfer a normal copy of the clotting factor gene
into the cells of people who have hemophilia. If expressed
properly, the transferred normal gene might be able to
compensate for the mutant allele these people naturally
carry. For this approach to succeed, the normal clotting
factor gene would have to be transferred into the cells that
produce clotting factor, or into their precursors.
Chapter 2
2.1 Carbohydrates and proteins are linear polymers. What
types of molecules combine to form these polymers?
ANS: Sugars combine to form carbohydrates; amino acids
combine to form proteins.
2.2 All cells are surrounded by a membrane; some cells are
surrounded by a wall. What are the differences between
cell membranes and cell walls?
ANS: Cell membranes are made of lipids and proteins; they
have a fluid structure. Cell walls are made of more rigid
materials such as cellulose.
2.3 What are the principal differences between prokaryotic
and eukaryotic cells?
ANS: In a eukaryotic cell, the many chromosomes are con -
tained within a membrane-bounded structure called the
nucleus; the chromosomes of prokaryotic cells are not
contained within a special subcellular compartment. Eukaryotic cells usually possess a well-developed inter -
nal system of membranes and they also have membrane-
bounded subcellular organelles such as mitochondria
and chloroplasts; prokaryotic cells do not typically have
a system of internal membranes (although some do), nor
do they possess membrane-bounded organelles.
2.4 Distinguish between the haploid and diploid states.
What types of cells are haploid? What types of cells are
diploid?
ANS: In the haploid state, each chromosome is represented
once; in the diploid state, each chromosome is repre -
sented twice. Among multicellular eukaryotes, gam -
etes are haploid and somatic cells are diploid.
2.5 Compare the sizes and structures of prokaryotic and
eukaryotic chromosomes.
ANS: Prokaryotic chromosomes are typically (but not always)
smaller than eukaryotic chromosomes; in addition, pro -
karyotic chromosomes are circular, whereas eukaryotic
chromosomes are linear. For example, the circular chro -
mosome of E. coli , a prokaryote, is about 1.4 mm in cir -
cumference. By contrast, a linear human chromosome
may be 10–30 cm long. Prokaryotic chromosomes also
have a comparatively simple composition: DNA, some
RNA, and some protein. Eukaryotic chromosomes are
more complex: DNA, some RNA, and a lot of protein.
2.6 With a focus on the chromosomes, what are the key
events during interphase and M phase in the eukaryotic
cell cycle?
ANS: During interphase, the chromosomes duplicate. During
M phase (mitosis), the duplicated chromosomes, each
consisting of two identical sister chromatids, condense
(a feature of prophase), migrate to the equatorial plane of
the cell (a feature of metaphase), and then split so that
their constituent sister chromatids are separated into dif -
ferent daughter cells (a feature of anaphase); this last
process is called sister chromatid disjunction.
2.7 Which typically lasts longer, interphase or M phase? Can
you explain why one of these phases lasts longer than the
other?
ANS: Interphase typically lasts longer than M phase. During
interphase, DNA must be synthesized to replicate all the
chromosomes. Other materials must also be synthesized
to prepare for the upcoming cell division.
2.8 In what way do the microtubule organizing centers of
plant and animal cells differ?
ANS: The microtubule organizing centers of animal cells have
distinct centrosomes, whereas the microtubule organiz -
ing centers of plant cells do not.
2.9 Match the stages of mitosis with the events they encom -
pass: Stages: (1) anaphase, (2) metaphase, (3) prophase,
and (4) telophase. Events: (a) reformation of the nucleo -
lus, (b) disappearance of the nuclear membrane,
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(c) condensation of the chromosomes, (d) formation of
the mitotic spindle, (e) movement of chromosomes to
the equatorial plane, (f) movement of chromosomes to
the poles, (g) decondensation of the chromosomes, (h)
splitting of the centromere, and (i) attachment of micro -
tubules to the kinetochore.
ANS: (1) Anaphase: (f), (h); (2) metaphase: (e), (i); (3) prophase:
(b), (c), (d); (4) telophase: (a), (g).
2.10 Arrange the following events in the correct temporal
sequence during eukaryotic cell division, starting with
the earliest: (a) condensation of the chromosomes,
(b) movement of chromosomes to the poles, (c) duplica -
tion of the chromosomes, (d) formation of the nuclear
membrane, (e) attachment of microtubules to the kineto -
chores, and (f) migration of centrosomes to positions on
opposite sides of the nucleus.
ANS: (c), (f), (a), (e), (b), (d).
2.11 In human beings, the gene for b-globin is located on chro -
mosome 11, and the gene for a-globin, which is another
component of the hemoglobin protein, is located on chro -
mosome 16. Would these two chromosomes be expected to
pair with each other during meiosis? Explain your answer.
ANS: Chromosomes 11 and 16 would not be expected to pair
with each other during meiosis; these chromosomes are
heterologues, not homologues.
2.12 A sperm cell from the fruit fly Drosophila melanogaster
contains four chromosomes. How many chromosomes
would be present in a spermatogonial cell about to enter
meiosis? How many chromatids would be present in a
spermatogonial cell at metaphase I of meiosis? How
many would be present at metaphase II?
ANS: There are eight chromosomes in a Drosophila spermato -
gonial cell about to enter meiosis. There are 16 chroma -
tids in a Drosophilia spermatogonial cell at metaphase I of
meiosis. There are eight chromatids in a Drosophilia cell
at metaphase II of meiosis.
2.13 Does crossing over occur before or after chromosome
duplication in cells going through meiosis?
ANS: Crossing over occurs after chromosomes have duplicated
in cells going through meiosis.
2.14 What visible characteristics of chromosomes indicate
that they have undergone crossing over during meiosis?
ANS: The chiasmata, which are visible late in prophase I of
meiosis, indicate that chromosomes have crossed over.
2.15 During meiosis, when does chromosome disjunction
occur? When does chromatid disjunction occur?
ANS: Chromosome disjunction occurs during anaphase I.
Chromatid disjunction occurs during anaphase II.
2.16 In Arabidopsis , is leaf tissue haploid or diploid? How
many nuclei are present in the female gametophyte? How many are present in the male gametophyte? Are
these nuclei haploid or diploid?
ANS: Leaf tissue is diploid. The female gametophyte contains
eight identical haploid nuclei. The male gametophyte
contains three identical haploid nuclei.
2.17 From the information given in T able 2.1 in this chapter,
is there a relationship between genome size (measured in
base pairs of DNA) and gene number? Explain.
ANS: Among eukaryotes, there does not seem to be a clear
relationship between genome size and gene number. For
example, humans, with 3.2 billion base pairs of genomic
DNA, have about 20,500 genes, and Arabidopsis plants,
with about 150 million base pairs of genomic DNA, have
roughly the same number of genes as humans. However,
among prokaryotes, gene number is rather tightly cor -
related with genome size, probably because there is so
little nongenic DNA.
2.18 Are the synergid cells in an Arabidopsis female gameto -
phyte genetically identical to the egg cell nestled between
them?
ANS: Yes.
2.19 A cell of the bacterium Escherichia coli , a prokaryote, con -
tains one chromosome with about 4.6 million base pairs
of DNA comprising 4288 protein-encoding genes. A cell
of the yeast Saccharomyces cerevisiae , a eukaryote, contains
about 12 million base pairs of DNA comprising 6268
genes, and this DNA is distributed over 16 distinct chro -
mosomes. Are you surprised that the chromosome of a
prokaryote is larger than some of the chromosomes of a
eukaryote? Explain your answer.
ANS: It is a bit surprising that yeast chromosomes are, on aver -
age, smaller than E. coli chromosomes because, as a rule,
eukaryotic chromosomes are larger than prokaryotic
chromosomes. Yeast is an exception because its genome—
not quite three times the size of the E. coli genome—is
distributed over 16 separate chromosomes.
2.20 Given the way that chromosomes behave during meiosis,
is there any advantage for an organism to have an even
number of chromosome pairs (such as Drosophila does),
as opposed to an odd number of chromosome pairs (such
as human beings do)?
ANS: No, there is no advantage associated with an even num -
ber of chromosomes. As long as the chromosomes come
in pairs, they will be able to synapse during prophase I
and then disjoin during anaphase I to distribute the
genetic material properly to the two daughter cells.
2.21 In flowering plants, two nuclei from the pollen grain par -
ticipate in the events of fertilization. With which nuclei
from the female gametophyte do these nuclei combine?
What tissues are formed from the fertilization events?
ANS: One of the pollen nuclei fuses with the egg nucleus in the
female gametophyte to form the zygote, which then
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develops into an embryo and ultimately into a sporo -
phyte. The other genetically functional pollen nucleus
fuses with two nuclei in the female gametophyte to form
a triploid nucleus, which then develops into a triploid
tissue, the endosperm; this tissue nourishes the develop -
ing plant embryo.
2.22 The mouse haploid genome contains about 2.9 × 109
nucleotide pairs of DNA. How many nucleotide pairs of
DNA are present in each of the following mouse cells:
(a) somatic cell, (b) sperm cell, (c) fertilized egg, (d) pri -
mary oocyte, (e) first polar body, and (f) secondary
spermatocyte?
ANS: (a) 5.8 × 109 nucleotide pairs (np); (b) 2.9 × 109 np;
(c) 5.8 × 109 np; (d) 11.6 × 109 np; (e) 5.8 × 109 np;
and (f) 5.8 × 109 np
2.23 Arabidopsis plants have 10 chromosomes (five pairs) in
their somatic cells. How many chromosomes are present
in each of the following: (a) egg cell nucleus in the female
gametophyte, (b) generative cell nucleus in a pollen
grain, (c) fertilized endosperm nucleus, and (d) fertilized
egg nucleus?
ANS: (a) 5, (b) 5, (c) 15, (d) 10.
Chapter 3
3.1 On the basis of Mendel’s observations, predict the results
from the following crosses with peas: (a) a tall (dominant
and homozygous) variety crossed with a dwarf variety;
(b) the progeny of (a) self-fertilized; (c) the progeny from
(a) crossed with the original tall parent; (d) the progeny
of (a) crossed with the original dwarf parent.
ANS: (a) All tall; (b) 3/4 tall, 1/4 dwarf; (c) all tall; (d) 1/2 tall,
1/2 dwarf.
3.2 Mendel crossed pea plants that produced round seeds
with those that produced wrinkled seeds and self-fertil -
ized the progeny. In the F2, he observed 5474 round
seeds and 1850 wrinkled seeds. Using the letters W and
w for the seed texture alleles, diagram Mendel’s crosses,
showing the genotypes of the plants in each generation.
Are the results consistent with the Principle of
Segregation?
ANS: Round ( WW ) × wrinkled ( ww) → F1 round ( Ww); F1
self-fertilized → F2 3/4 round (2 WW ; 1 Ww), 1/4 wrin -
kled ( ww). The expected results in the F2 are 5493 round,
1831 wrinkled. T o compare the observed and expected
results, compute c2 with one degree of freedom;
(5474 − 5493)2/5493 = (1850 − 1831)2/1831 = 0.263,
which is not significant at the 5% level. Thus, the results
are consistent with the Principle of Segregation.
3.3 A geneticist crossed wild, gray-colored mice with white
(albino) mice. All the progeny were gray. These progeny
were intercrossed to produce an F2, which consisted of
198 gray and 72 white mice. Propose a hypothesis to explain these results, diagram the crosses, and compare
the results with the predictions of the hypothesis.
ANS: The data suggest that coat color is controlled by a single
gene with two alleles, C (gray) and c (albino), and that C
is dominant over c. On this hypothesis, the crosses are
gray ( CC) × albino ( cc) → F1 gray ( Cc); F1 × F1 → 3/4
gray (2 CC: 1 Cc), 1/4 albino ( cc). The expected results in
the F2 are 203 gray and 67 albino. T o compare the
observed and expected results, compute c2 with one
degree of freedom: (198 − 203)2/203 + (67 − 72)2/72 =
0.470, which is not significant at the 5% level. Thus, the
results are consistent with the hypothesis.
3.4 A woman has a rare abnormality of the eyelids called
ptosis, which prevents her from opening her eyes com -
pletely. This condition is caused by a dominant allele,
P. The woman’s father had ptosis, but her mother had
normal eyelids. Her father’s mother had normal
eyelids.
(a) What are the genotypes of the woman, her father, and
her mother?
(b) What proportion of the woman’s children will have
ptosis if she marries a man with normal eyelids?
ANS: (a) Woman’s genotype Pp, father’s genotype Pp, mother’s
genotype pp; (b) ½
3.5 In pigeons, a dominant allele C causes a checkered pat -
tern in the feathers; its recessive allele c produces a plain
pattern. Feather coloration is controlled by an indepen -
dently assorting gene; the dominant allele B produces
red feathers, and the recessive allele b produces brown
feathers. Birds from a true-breeding checkered, red vari -
ety are crossed to birds from a true-breeding plain,
brown variety.
(a) Predict the phenotype of their progeny.
(b) If these progeny are intercrossed, what phenotypes
will appear in the F2 and in what proportions?
ANS: (a) Checkered, red ( CC BB ) × plain, brown ( cc bb) → F1
all checkered, red ( Cc Bb ); (b) F2 progeny: 9/16 check -
ered, red ( C- B-), 3/16 plain, red ( cc B-), 3/16 checkered,
brown ( C- bb), 1/16 plain, brown ( cc bb).
3.6 In mice, the allele C for colored fur is dominant over the
allele c for white fur, and the allele V for normal behavior
is dominant over the allele v for waltzing behavior, a
form of dis-coordination. Given the genotypes of the
parents in each of the following crosses:
(a) Colored, normal mice mated with white, normal mice
produced 29 colored, normal, and 10 colored, waltzing
progeny
(b) Colored, normal mice mated with colored, normal
mice produced 38 colored, normal, 15 colored, waltzing,
11 white, normal, and 4 white, waltzing progeny
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(c) Colored, normal mice mated with white, waltzing
mice produced 8 colored, normal, 7 colored, waltzing,
9 white, normal, and 6 white, waltzing progeny.
ANS: (a) colored, normal ( CC Vv ) × white, normal ( cc Vv )
(b) colored, normal ( Cc Vv ) × colored, normal ( Cc Vv );
(c) colored, normal ( Cc Vv ) × white, waltzing ( cc vv).
3.7 In rabbits, the dominant allele B causes black fur and the
recessive allele b causes brown fur; for an independently
assorting gene, the dominant allele R causes long fur and
the recessive allele r (for rex) causes short fur. A homozy -
gous rabbit with long, black fur is crossed with a rabbit
with short, brown fur, and the offspring are intercrossed.
In the F2, what proportion of the rabbits with long, black
fur will be homozygous for both genes?
ANS: Among the F2 progeny with long, black fur, the geno -
typic ratio is 1 BB RR : 2 BB Rr : 2 Bb RR : 4 Bb Rr ; thus, 1/9
of the rabbits with long, black fur are homozygous for
both genes.
3.8 In shorthorn cattle, the genotype RR causes a red coat,
the genotype rr causes a white coat, and the genotype
Rr causes a roan coat. A breeder has red, white, and
roan cows and bulls. What phenotypes might be
expected from the following matings and in what
proportions?
(a) Red × red
(b) Red × roan
(c) Red × white
(d) Roan × roan.
ANS: (a) All red; (b) 1/2 red, 1/2 roan; (c) all roan; (d) 1/4 red,
1/2 roan, 1/4 white
3.9 How many different kinds of F1 gametes, F2 genotypes,
and F2 phenotypes would be expected from the following
crosses:
(a) AA × aa;
(b) AA BB × aa bb ;
(c) AA BB CC × aa bb cc ?
(d) What general formulas are suggested by these
answers?
ANS:
F1 Gametes F2 Genotypes F2 Phenotypes
(a) 2 3 2
(b) 2 × 2 = 4 3 × 3 = 9 2 × 2 = 4
(c) 2 × 2 × 2 = 8 3 × 3 × 3 = 27 2 × 2 × 2 = 8
(d) 2n 3n 2n, where n is the
number of genes 3.10 A researcher studied six independently assorting genes in
a plant. Each gene has a dominant and a recessive allele:
R black stem, r red stem; D tall plant, d dwarf plant; C full
pods, c constricted pods; O round fruit, o oval fruit; H
hairless leaves, h hairy leaves; W purple flower, w white
flower. From the cross (P1) Rr Dd cc Oo Hh Ww × (P2)
Rr dd Cc oo Hh ww,
(a) How many kinds of gametes can be formed by P1?
(b) How many genotypes are possible among the prog -
eny of this cross?
(c) How many phenotypes are possible among the
progeny?
(d) What is the probability of obtaining the Rr Dd cc Oo
hh ww genotype in the progeny?
(e) What is the probability of obtaining a black, dwarf,
constricted, oval, hairy, purple phenotype in the
progeny?
ANS: (a) 2 × 2 × 1 × 2 × 2 × 2 = 32; (b) 3 × 2 × 2 × 2 × 3 ×
2 = 144; (c) 2 × 2 × 2 × 2 × 2 × 2 = 64; (d) (1/2) ×
(1/2) × (1/2) × (1/2) × (1/4) × (1/2) = 1/128; (e) (3/4) ×
(1/2) × (1/2) × (1/2) × (1/4) × (1/2) = 3/256.
3.11 For each of the following situations, determine the
degrees of freedom associated with the c2 statistic and
decide whether or not the observed c2 value warrants
acceptance or rejection of the hypothesized genetic ratio.
Hypothesized Ratio Observed− c2
(a) 3:1 7.0
(b) 1:2:1 7.0
(c) 1:1:1:1 7.0
(d) 9:3:3:1 5.0
ANS: (a) 1, reject; (b) 2, reject; (c) 3, accept; (d) 3, accept.
3.12 Mendel testcrossed pea plants grown from yellow, round
F1 seeds to plants grown from green, wrinkled seeds and
obtained the following results: 31 yellow, round; 26
green, round; 27 yellow, wrinkled; and 26 green, wrin -
kled. Are these results consistent with the hypothesis that
seed color and seed texture are controlled by indepen -
dently assorting genes, each segregating two alleles?
ANS: On the hypothesis, the expected number in each class
is 27.5; c2 with three degrees of freedom is calculated as
(31 − 27.5)2/27.5 + (26 − 27.5)2/27.5 + (27 − 27.5)2/27.5 +
(26 − 27.5)2/27.5 = 0.618, which is not significant at the
5% level. Thus, the results are consistent with the hypoth -
esis of two independently assorting genes, each segregating
two alleles.
3.13 Perform a chi-square test to determine if an observed
ratio of 30 tall to 20 dwarf pea plants is consistent with
an expected ratio of 1:1 from the cross Dd × dd.
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ANS: c2 = (30 − 25)2/25 + (20 − 25)2/25 = 2, which is less
than 3.84, the 5 percent critical value for a chi-square
statistic with one degree of freedom; consequently, the
observed segregation ratio is consistent with the expected
ratio of 1:1.
3.14 Seed capsules of the Shepherd’s purse are either triangu -
lar or ovoid. A cross between a plant with triangular seed
capsules and a plant with ovoid seed capsules yielded F1
hybrids that all had triangular seed capsules. When these
F1 hybrids were intercrossed, they produced 80 F2 plants,
72 of which had triangular seed capsules and 8 of which
had ovoid seed capsules. Are these results consistent with
the hypothesis that capsule shape is determined by a sin -
gle gene with two alleles?
ANS: If capsule shape is determined by a single gene with two
alleles, the F2 plants should segregate in a 3:1 ratio. T o
test for agreement between the observed segregation
data and the expected ratio, compute the expected num -
ber of plants with either triangular or ovoid seed cap -
sules: (3/4) × 80 = 60 triangular and (1/4) × 80 = 20
ovoid; then compute a c2 statistic with one degree of
freedom: c2 = (72 − 60)2/60 + (8 − 20)2/20 = 9.6, which
exceeds the critical value of 3.84. Consequently, the data
are inconsistent with the hypothesis that capsule shape is
determined by a single gene with two alleles.
3.15 Albinism in humans is caused by a recessive allele a.
From marriages between people known to be carriers
(Aa) and people with albinism ( aa), what proportion of
the children would be expected to have albinism? Among
three children, what is the chance of one without albi -
nism and two with albinism?
ANS: Half the children from Aa × aa matings would have
albinism. In a family of three children, the chance that
one will be unaffected and two affected is 3 × (1/2)1 ×
(1/2)2 = 3/8.
3.16 If both husband and wife are known to be carriers of the
allele for albinism, what is the chance of the following
combinations in a family of four children: (a) all four
unaffected; (b) three unaffected and one affected; (c) two
unaffected and two affected; (d) one unaffected and three
affected?
ANS: (a) (3/4)4 = 81/256; (b) 4 × (3/4)3 × (1/4)1 = 108/256; (c)
6 × (3/4)2 × (1/4)2 = 54/256; (d) 4 × (3/4)1 × (1/4)3 =
12/256.
3.17 In humans, cataracts in the eyes and fragility of the bones
are caused by dominant alleles that assort independently.
A man with cataracts and normal bones marries a woman
without cataracts but with fragile bones. The man’s
father had normal eyes, and the woman’s father had nor -
mal bones. What is the probability that the first child of
this couple will (a) be free from both abnormalities; (b)
have cataracts but not have fragile bones; (c) have fragile
bones but not have cataracts; (d) have both cataracts and
fragile bones?ANS: Man ( Cc ff ) × woman ( cc Ff ). (a) cc ff, (1/2) × (1/2) = 1/4;
(b) Cc ff, (1/2) × (1/2) = 1/4; (c) cc Ff, (1/2) × (1/2) = 1/4;
(d) Cc Ff , (1/2) × (1/2) = 1/4.
3.18 In generation V in the pedigree in Figure 3.15, what is
the probability of observing seven children without the
cancer-causing mutation and two children with this
mutation among a total of nine children?
ANS: 9!/(7! 2!) × (1/2)7 × (1/2)2 = 0.07
3.19 If a man and a woman are heterozygous for a gene, and if
they have three children, what is the chance that all three
will also be heterozygous?
ANS: (1/2)3 = 1/8
3.20 If four babies are born on a given day: (a) What is the
chance that two will be boys and two will be girls?
(b) What is the chance that all four will be girls? (c) What
combination of boys and girls among four babies is most
likely? (d) What is the chance that at least one baby will
be a girl?
ANS: (a) 4 × (1/2)2 × (1/2)2 = 4/16; (b) (1/2)4 = 1/16; (c) 2
boys, girls; (d) 1 − probability that all four are boys = 1
− (1/2)4 = 15/16.
3.21 In a family of six children, what is the chance that at least
three are girls?
ANS: (20/64) + (15/64) + (6/64) + (1/64) = 42/64
3.22 The following pedigree shows the inheritance of a domi -
nant trait. What is the chance that the offspring of the
following matings will show the trait: (a) III-1 × III-3;
(b) III-2 × III-4?
I
II
III2 1
34 2 1
34 2 1
ANS: (a) zero; (b) 1/2
3.23 The following pedigree shows the inheritance of a reces -
sive trait. Unless there is evidence to the contrary, assume
that the individuals who have married into the family do
not carry the recessive allele. What is the chance that the
offspring of the following matings will show the trait: (a)
III-1 × III-12; (b) II-4 × III-14; (c) III-6 × III-13; (d)
IV-1 × IV-2?
I
12
1
12342II
III3
56784 7
14 15 16 178 5
109
2 111 12 136
ANS: (a) (1/2) × (1/4) = 1/8; (b) (1/2) × (1/2) × (1/4) = 1/16;
(c) (2/3) × (1/4) = 1/6; (d) (2/3) × (1/2) × (1/2) × (1/4)
= 1/24
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3.24 In the following pedigrees, determine whether the trait is
more likely to be due to a dominant or a recessive allele.
Assume the trait is rare in the population.
I
12
1
1223II
III
IV
V
(a)5
346
2345 1
1
I
II
III
IV12
1 234
(b)5
45 12 36 78
12 3
ANS: (a) Recessive; (b) dominant.
3.25 In pedigree ( b) of Problem 3.24, what is the chance that
the couple III-1 and III-2 will have an affected child?
What is the chance that the couple IV-2 and IV-3 will
have an affected child?
ANS: For III-1 × III-2, the chance of an affected child is 1/2.
For IV-2 × IV-3, the chance is zero.
3.26 Peas heterozygous for three independently assorting
genes were intercrossed.
(a) What proportion of the offspring will be homozy -
gous for all three recessive alleles?
(b) What proportion of the offspring will be homozy -
gous for all three genes?
(c) What proportion of the offspring will be homozy -
gous for one gene and heterozygous for the other two?
(d) What proportion of the offspring will be homozy -
gous for the recessive allele of at least one gene?
ANS: (a) (1/4)3 = 1/64; (b) (1/2)3 = 1/8; (c) 3 × (1/2)1 ×
(1/2)2 = 3/8; (d) 1 − probability that the offspring is not
homozygous for the recessive allele of any gene = 1 − (3/4)3
= 37/64.
3.27 The following pedigree shows the inheritance of a reces -
sive trait. What is the chance that the couple III-3 and
III-4 will have an affected child?
I
12
12II
III
24 13ANS: 1/2
3.28 A geneticist crosses tall pea plants with short pea plants.
All the F1 plants are tall. The F1 plants are then allowed
to self-fertilize, and the F2 plants are classified by height:
62 tall and 26 short. From these results, the geneticist
concludes that shortness in peas is due to a recessive
allele ( s) and that tallness is due to a dominant allele ( S).
On this hypothesis, 2/3 of the tall F2 plants should be
heterozygous Ss. T o test this prediction, the geneticist
uses pollen from each of the 62 tall plants to fertilize the
ovules of emasculated flowers on short pea plants. The
next year, three seeds from each of the 62 crosses are
sown in the garden and the resulting plants are grown to
maturity. If none of the three plants from a cross is short,
the male parent is classified as having been homozygous
SS; if at least one of the three plants from a cross is short,
the male parent is classified as having been heterozygous
Ss. Using this system of progeny testing, the geneticist
concludes that 29 of the 62 tall F2 plants were homozy -
gous SS and that 33 of these plants were heterozygous Ss.
(a) Using the chi-square procedure, evaluate these results
for goodness of fit to the prediction that 2/3 of the tall F2
plants should be heterozygous.
(b) Informed by what you read in A Milestone in Genet -
ics: Mendel’s 1866 Paper, which you can find in the Stu -
dent Companion Site, explain why the geneticist’s
procedure for classifying tall F2 plants by genotype is not
definitive.
(c) Adjust for the uncertainty in the geneticist’s classifi -
cation procedure and calculate the expected frequencies
of homozygotes and heterozygotes among the tall
F2 plants.
(d) Evaluate the predictions obtained in (c) using the chi-
square procedure.
ANS: (a) The observed numbers, expected numbers, and chi-
square calculation are laid out in the following table:
Observed Expected (Obs − Exp)2
/Exp
Dominant
homozygotes
(SS)29 62 × 1/3 = 20.7 3.33
Heterozygotes
(Ss)33 62 × 2/3 = 41.3 1.67
T otal 62 62 5.00
The total chi-square value is greater than the critical
value for a chi-square statistic with one degree of free -
dom (3.84). Therefore, we reject the hypothesis that the
expected proportions are 1/3 and 2/3.
(b) The problem with the geneticist’s classification
procedure is that it allows for a heterozygote to be
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