Chemistry 12
Final Exam Form A
May 4, 2001
Name
____________________
Section
____________________
Student No. ____________________
IMPORTANT: On the scantron (answer sheet), you MUST clearly fill your name, your
student number, section number, and test form (white cover = test form A; yellow cover =
test form B). Use a #2 pencil.
In all questions involving gases, assume that the ideal-gas laws hold, unless the question
specifically refers to the non-ideal behavior.
_____________________________________________________________________________________________
1. Which of the following sets of quantum numbers corresponds to one of the three highestenergy electrons in the ground state of phosphorous?
a. n = 4, l = 0, ml = 0
b. n = 3, l = 2, ml = 1
c. n = 4, l = 1, ml = –1
d. n = 3, l = 1, ml = 0
e. n = 5, l = 3, ml = 2
--------------------------------------------------------------------------------------------------------------------2. Which of the following molecules does not obey the octet rule?
a. SiF4
b. PCl5
c. HCN
d. CCl4
e. NF3
---------------------------------------------------------------------------------------------------------------------
There are 39 questions on this exam. Check that you have done all of the problems and filled in
the first 39 bubbles on the scantron. The maximum score on this exam is 40 points.
Exam policy
•
•
•
•
Calculators with text-programmable memory are not allowed.
Relevant data and formulas, including the periodic table, are attached at the end of this
exam.
Your grade will be based only on what is on the scantron form.
The answer key will be posted on the web after the exam (under "News").
•
a. 6
b. 7
c. 8
d. 9
e. 10
--------------------------------------------------------------------------------------------------------------------4. What is the number of unpaired electrons in the ground state Ni atom?
Hints
•
3. What is the total number of lone pairs in the best resonance structure of COCl2 (carbon is the
central atom)?
As you read the question, underline or circle key words to highlight them for yourself.
Avoid errors from "misreading" the question.
There is no penalty for guessing.
a. 5
b. 4
c. 3
d. 2
e. 1
---------------------------------------------------------------------------------------------------------------------
1
2
5. Which of the following molecules has resonance structures?
a.
b.
c.
d.
e.
NH3
H2O
NF3
C2H6
O3
9. For the following reaction at equilibrium, which of the listed perturbations will cause an
increase in the equilibrium concentration of the reactant?
PCl5 (g)
--------------------------------------------------------------------------------------------------------------------6. Which of the following statements is true?
a. Energy is required to create covalent bonds.
b. Energy is required to break covalent bonds.
c. Some bonds require energy to create. Others require energy to break.
d. All C-C single bonds have exactly the same bond dissociation energies.
e. A double bond has exactly twice the dissociation energy of the corresponding single
bond.
--------------------------------------------------------------------------------------------------------------------7. The value of Kc for the following reaction is 0.25.
SO2 (g) + NO2 (g) ! SO3 (g) + NO (g)
What is the value of Kc for the reaction shown below?
2SO3 (g) + 2NO (g) ! 2SO2 (g) + 2NO2 (g)
a. 0.50
b. 0.063
c. 8.0
d. 4.0
e. 16
--------------------------------------------------------------------------------------------------------------------8. Consider the equilibrium:
2NO (g) + Cl2 (g) ! 2ClNO (g)
Suppose that 0.300 mol of NO, 0.200 mol of Cl2, and 0.500 mol of ClNO were placed in a 25.0 L
vessel and allowed to reach equilibrium. At equilibrium, 0.600 mol of ClNO was present. What
is the number of moles of NO present at equilibrium?
a.
b.
c.
d.
e.
--------------------------------------------------------------------------------------------------------------------3
Chlorine gas is removed from the reaction vessel.
The temperature of the reaction vessel is increased.
The volume of the reaction vessel is decreased.
Ar (g) is added to the reaction vessel.
The pressure of the system is decreased.
--------------------------------------------------------------------------------------------------------------------10. What is the hybridization of C1 and the O-C-O bond angle in the following molecule?
O
H3C
C1
O
CH3
Note: Lone pairs and the molecular geometry are not shown explicitly in this structure.
a.
b.
c.
d.
e.
sp3
sp
sp2
sp3
sp2
120º
180º
120º
109.5º
109.5º
--------------------------------------------------------------------------------------------------------------------11. What is the molecular geometry of ClF3?
a. T-shaped
b. trigonal planar
c. trigonal bipyramidal
d. trigonal pyramidal
e. seesaw
--------------------------------------------------------------------------------------------------------------------12. Which one of the following molecules is nonpolar?
a.
b.
c.
d.
e.
a. 0.100 mol
b. 0.150 mol
c. 0.200 mol
d. 0.250 mol
e. 0.300 mol
∆Ho = 87.9 kJ
PCl3 (g) + Cl2 (g)
XeF4
SF4
NO2─
NH3
BrF5
---------------------------------------------------------------------------------------------------------------4
13. Glycerin (C3H8O3) is a nonvolatile nonelectrolyte. What is the vapor pressure at 25 oC of a
solution made by adding 9 mol of glycerin to 270.0 mL of water? (assume the vapor
pressure of pure water at 25 oC is 23.8 torr, and the density of water is 1 g/mL)
a. 793 torr
b. 0.768 torr
c. 0.793 torr
d. 23.8 torr
e. 14.9 torr
a. 1.0 atm
b. 2.0 atm
c. 3.0 atm
d. 4.0 atm
e. 5.0 atm
--------------------------------------------------------------------------------------------------------------------14. Consider the following three balanced chemical reactions run under conditions of a constant
temperature (28 oC) and a constant volume (1 L). Which reaction would not result in a
change in pressure?
I. H2(g) + Cl2(g) " 2HCl(g)
II. 2NH3(g) " 2N2(g) + 3H2(g)
III. NH4NO2(s) " N2(g) + 2H2O(g)
a. I only
b. II only
c. III only
d. I and II only
e. I, II, and III
18. Caffeine has a molecular weight of 194.2 g/mol and mass composition of 49.98% C, 5.19%
H, 28.25% N, and 16.48% O. What is the molecular formula of caffeine?
a. C10H14N2O2
b. C8H10N4O2
c. C8H10N2O
d. C4H5N2O
e. C5H7NO
19. Which of the following liquids has extensive hydrogen bonding?
a. CH4
b. H2NNH2
c. CH3F
d. H3C-O-CH3
e. CH2Cl2
---------------------------------------------------------------------------------------------------------------------
100 L
200 L
300 L
400 L
500 L
20. List the following substances in order of increasing normal boiling points.
BaCl2, CO, HF, Ne
--------------------------------------------------------------------------------------------------------------------16. The density of an unknown gas is 1.25 g/L at STP. Which of the following is most likely to
be the unknown gas?
a.
b.
c.
d.
e.
---------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------------------------15. The volume of a large, irregularly shaped tank is determined as follows. The tank is first
evacuated, and then it is connected to a 50.0 L cylinder of compressed helium gas. The
gas pressure in the cylinder, originally at 21 atm, falls to 7 atm without a change in
temperature. What is the volume of the tank?
a.
b.
c.
d.
e.
17. A 3.0 L sample of He gas at 6 atm and 25 oC, and a 4.5 L sample of Ne gas at 2.0 atm and 25
o
C are completely transferred to a 9.0 L flask, at constant temperature. What is the total
pressure in the 9.0 L flask?
CO
O2
C2H6
NH3
Cl2
a. CO < HF < Ne < BaCl2
b. HF < CO < BaCl2 < Ne
c. Ne < CO < HF < BaCl2
d. BaCl2 < HF < CO < Ne
e. Ne < CO < BaCl2 < HF
---------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------5
6
21. Which of the following aqueous solutions will show the largest freezing point depression?
a. 0.01 M HCl
b. 0.03 M CaBr2
c. 0.02 M Ca(NO3)2
d. 0.02 M Al(NO3)3
e. 0.02 M Al2(SO4)3
25. How many grams of F2 need to be consumed to produce 338 kJ of heat in the following
reaction?
H2 + F2 " 2HF
-----------------------------------------------------------------------------------------------------------------22. Which of the following represents the net ionic equation for the reaction of NH3 (aq) and
HBr (aq)?
a. NH3 (aq) + HBr (aq) " NH4+ (aq) + Br─ (aq)
b. HBr (aq) " NH4Br (aq)
c. NH3 (aq) + H+ (aq) + Br─ (aq) " NH4Br (aq)
d. NH3 (aq) + H+ (aq) " NH4+ (aq)
e. N3─ (aq) + 3H+ (aq) + H+ (aq) + Br─ (aq) " NH4Br (aq)
--------------------------------------------------------------------------------------------------------------------23. According to the phase diagram below, what phase transition(s) will take place when CO2 is
heated from ─70 °C to 31 °C at a constant pressure of 20 atm?
Pressure (atm)
a. deposition
b. condensation, then freezing
c. melting, then vaporization
d. sublimation
e. vaporization
∆H°f = –271 kJ
a. 15.2 g
b. 47.4 g
c. 23.7 g
d. 30.5 g
e. 11.8 g
--------------------------------------------------------------------------------------------------------------------26. Titanium (IV) oxide, one of the most commonly used white paint pigments, is produced by
the following reaction:
TiCl4(g) + 2H2O(g) " TiO2(g) + 4HCl(g)
∆H°rxn = –66 kJ
Given the following heats of formation (∆H°f), what is ∆H°f for TiO2(g)?
∆H°f [TiCl4(g)] = –763 kJ/mol
∆H°f [H2O(g)] = –242 kJ/mol
∆H°f [HCl(g)] = –92 kJ/mol
a. 813 kJ/mol
b. –32 kJ/mol
c. –945 kJ/mol
d. 1129 kJ/mol
e. –979 kJ/mol
---------------------------------------------------------------------------------------------------------------------
73
20
5
1
27. Which of the following atoms has the smallest first ionization energy?
-78 -65
31
Temperature (oC)
--------------------------------------------------------------------------------------------------------------------24. Which of the following compounds has the highest vapor pressure at 0 °C?
a. H3C
(CH2)3 CH3
b.
H 3C
(CH2)2 CH2OH
CH2 CH2OH
OH
CH3
d. H3C
c. HOH2C
e.
C CH3
HOH2C
CH CH2OH
CH3
---------------------------------------------------------------------------------------------------------------------
a. Ne
b. O
c. N
d. Ar
e. Na
--------------------------------------------------------------------------------------------------------------------28. Which of the following orderings of atomic/ionic radii is correct?
a. Li < Li+ < He
b. N < O < F
c. Br < Cl < F
d. Li < Na < K
e. Mg < Mg+ < Mg2+
-------------------------------------------------------------------------------------------------------------------
7
8
29. Which of the following would be expected to have the lowest melting point?
a. NaCl
b. MgO
c. MgS
d. NaBr
e. LiCl
--------------------------------------------------------------------------------------------------------------------30. At 20 °C, Henry’s law constant for Ar is half of that for Kr. If a gaseous Ar/Kr mixture
containing 20% molar fraction of Kr is placed over water at 20 °C, what is the ratio of
concentrations of Ar to Kr in water?
a. 0.5
b. 1.0
c. 2.0
d. 3.0
e. 4.0
--------------------------------------------------------------------------------------------------------------------31. Which of the following would be expected to be most soluble in H2O?
a. ethanol
b. benzene
c. butane
d. bromine
e. trichloromethane
--------------------------------------------------------------------------------------------------------------------32. What is the correct expression for the equilibrium constant for the following reaction?
6CO2 (g) + 6H2O (g) ! C6H12O6 (s) + 6 O2 (g)
a. Kc =
b. Kc =
[O 2 ]6
33. Which of the following statements correctly describes all systems at equilibrium?
I. The rate of the forward reaction is equal to the rate of the reverse reaction.
II. The concentrations of the reactants and products remain constant.
III. Concentrations of products are equal to the concentrations of reactants.
IV. The heat of formation of the products equals the heat of formation of the reactants.
a. III only
b. I and II, only
c. II and III, only
d. III and IV, only
e. IV only
--------------------------------------------------------------------------------------------------------------------34. What is the correct systematic (IUPAC) name for the following molecule?
a. 1, 2, 3- trimethylbenzene
b. 1, 2, 3- trimethylhexane
c. 1, 2, 3- trimethylcyclononane
d. 1, 2, 3- trimethylcyclohexane
e. 1, 2, 3- trimethylcycloheptane
------------------------------------------------------------------------------------------------------------------35. Which two functional groups are present in aspirin?
O
OH
aspirin
O
O
[CO2 ]6
a. aldehyde and amide
b. carboxylic acid and ester
c. carboxylic acid and ether
d. alcohol and ester
e. ketone and aldehyde
[CO 2 ]6
[O2 ]6
c. Kc =
[C6 H12 O6 ][O2 ]6
[CO2 ]6 [ H 2O]6
d. Kc =
[CO2 ]6 [ H 2 O]6
[C 6 H 12 O6 ][O2 ]6
--------------------------------------------------------------------------------------------------------------------
[O2 ]6
[CO 2 ]6 [ H 2 O ]6
---------------------------------------------------------------------------------------------------------------------
e. Kc =
9
10
36. Consider the following reaction at a constant temperature for which Kp = 7.0:
H2 (g) + I2 (g)
Constants & Equations
2HI (g)
Hydrogen (H2, 0.150 moles), I2 (0.500 moles), and HI (0.600 moles) are introduced into a 2.0 L
vessel. Which one of the following statements is true at the moment of mixing?
a. The system is at equilibrium.
b. The system is at equilibrium, but adding a catalyst will cause the reaction to proceed to
the right.
c. The system is not at equilibrium, and will proceed to the left to achieve equilibrium.
d. The system is not at equilibrium, and will proceed to the right to achieve equilibrium.
e. The system is not at equilibrium, and it cannot achieve equilibrium.
--------------------------------------------------------------------------------------------------------------------37. What is the osmotic pressure of a 0.100 M solution of a nonelectrolyte at 20 oC?
a. 1.00 atm
b. 2.41 atm
c. 0.164 atm
d. 4.82 atm
e. 1.64 atm
--------------------------------------------------------------------------------------------------------------------38. Which species is primarily responsible for absorbing ultraviolet radiation in the atmosphere?
a. H2O
b. N2
c. CO2
d. CCl2F2
e. O3
--------------------------------------------------------------------------------------------------------------------39. Which of the following processes is endothermic?
a. 2H2 (g) + O2 (g) " 2H2O (g)
b. H2O (g) " H2O (l)
c. CH4 (g) + 2O2 (g) " CO2 (g) + 2H2O (g)
d. CO2 (g) " CO2 (s)
e. H2O (l) " H2O (g)
________________________________________________________________________
End of the exam
11
1 J = 1 kg· m2·s-2
RH = 2.18 × 10-18 J
c = 3.00 × 108 m·s-1
e = –1.60 × 10-19 C
h = 6.63 × 10-34 J·s
1 D = 3.33 × 10-30 C·m
N = 6.02 × 1023 mol-1
R = 8.314 J/(mol·K)
R = 0.08206 L·atm/(mol·K)
R = 1.987 cal/(mol·K)
1 atm = 760 mmHg = 760 torr
1 atm = 1.01325 × 105 Pa
1 atm = 1.01.325 kPa
1 mol of gas at STP occupies
V = 22.41 L
(P + n2a/V2)(V - nb) = nRT
PV = nRT
d= PM/(RT)
π = (n/V)RT
c = λν
E = hν
 1
1 
∆E = R H  2 − 2 
nf 
 ni
λ = h/mv
µ=Qr
E = kLQ1Q2/d
q = m · c · ∆T
Pi = Xi Ptot
u=
r1
=
r2
3RT
M
M2
M1
Cg = kP g
P A = XAPAo
∆Tb = Kbm
∆Tf = Kfm
∆H°rxn = Σ n ∆H°f (products) − Σ m ∆H°f (reactants)
∆H°rxn = Σ (∆H of bonds broken) − Σ (∆H of bonds formed)
12
PERIODIC TABLE of the ELEMENTS (2001)
MAIN GROUPS
1A
1
1
H
1.008
3
8A
18
2
2A
2
4
He
3A
13
5
4A
14
6
5A
15
7
6A
16
8
7A
17
9
4.003
Li
Be
F
Ne
9.012
10.811
12.011
14.007
15.999
18.998
20.180
11
12
13
14
15
16
17
TRANSITION METALS
Na
Mg
22.990
24.305
20
6B
6
24
7B
7
25
3B
3
21
4B
4
22
5B
5
23
V
Cr
Mn
47.867
50.942
51.996
54.938
K
Ca
Sc
39.098
40.078
44.956
37
B
Ti
58.693
S
Cl
Ar
32.066
35.453
39.948
Cu
Zn
Ga
Ge
As
Se
Br
Kr
63.546
65.39
69.723
72.61
74.992
78.96
79.904
83.80
32
35
36
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
48
49
In
Sn
Sb
Te
52
53
I
Xe
92.906
95.94
[98]
101.07
102.90
106.42
107.87
112.41
114.82
118.71
121.76
127.60
126.90
131.29
78
79
80
81
82
51
34
91.224
77
50
33
Y
76
47
31
39
75
46
P
30.974
88.906
74
45
Si
28.086
38
73
44
Al
26.982
Sr
72
43
58.933
18
2B
12
30
1B
11
29
87.62
57
42
Ni
55.845
O
Rb
56
41
Co
8B
10
28
N
85.468
55
40
Fe
8B
9
27
8B
8
26
C
10
6.941
19
83
84
85
54
86
Cs
Ba
La*
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
132.91
137.33
138.91
178.49
180.95
183.84
186.21
190.23
192.22
195.08
196.97
200.59
204.38
207.2
208.98
[209]
[210]
[222]
Fr
Ra
Ac**
89
104
105
106
107
108
109
110
111
112
114
116
118
[223]
[226]
[227]
[261]
[262]
[266]
[264]
[265]
[268]
[269]
[272]
[277]
[285]
[289]
[293]
87
ANSWER KEY
Chem 12 Final Exam
May 4, 2001
MAIN GROUPS
88
Rf
Db
58
* LANTHANOIDS
59
Bh
60
Hs
61
Mt
62
63
64
65
66
67
68
69
70
71
Ce
Pr
Nd
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
140.12
140.91
144.24
[145]
150.36
151.96
157.25
158.92
162.50
164.93
167.26
168.93
173.04
174.97
90
** ACTINOIDS
Sg
94
95
96
99
100
101
Th
Pa
U
Np
Pu
Am
Cm
Bk
Cf
Es
Fm
Md
No
Lr
232.04
321.04
91
238.03
92
[237]
93
[244]
[243]
[247]
[247]
97
[251]
98
[252]
[257]
[258]
[259]
102
[262]
103
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
D
B
C
D
E
B
E
C
C
C
A
A
E
A
A
A
C
B
B
C
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
13
14
E
D
C
D
B
C
E
D
D
C
A
E
B
D
B
D
B
E
E