CHEMISTRY 112
Final Exam
June 25, 2012
FORM A
--------------------------------------------------------------------------------------------------------------1.
What is the conjugate acid of pyridine, C5H5N?
A.
C5H4NH
B.
C5H5NH
C.
C5H4N
D.
C5H5NOH
E.
C5H5NH
+
--------------------------------------------------------------------------------------------------------------2.
What is the pH of a 0.025 M solution of KOH?
A.
7
B.
1.6
C.
12.4
D.
12.1
E.
1.9
-----------------------------------------------------------------------------------------------------------3.
What substances are produced at the cathode of a nicad battery during discharge?
The reaction that occurs during discharge is given below.
2NiO(OH)(s) + Cd(s) + 2H2O + 2OH–(aq) → 2 Ni(OH)2(s) + Cd(OH)2(s) + 2OH–(aq)
A.
Cd(s) and OH–(aq)
B.
Ni(OH)2 and OH–(aq)
C.
NiO(OH)(s) and H2O(l)
D.
NiO(OH)(s) and Cd(s)
E.
Cd(OH)2(s) and OH–(aq)
---------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------4.
What is the electron configuration of Cu+2
A.
[Ar] 4s23d8
B.
[Ar] 4s13d8
C.
[Ar] 4s23d7
D.
[Ar] 3d10
E.
[Ar] 3d9
-----------------------------------------------------------------------------------------------------------5.
Which of the following coordination compounds is likely to be colored?
A.
B.
C.
Sc2O3
[Zn(NH3)4]2+
[Ti(H2O)6]3+
D.
[CdCl4]2−
E
[NbF6]−
--------------------------------------------------------------------------------------------------------------6.
Silicon carbide, SiC, forms one of the hardest crystals known because it is a(n)
A.
metallic solid
B.
Molecular solid
C.
Plastic
D.
Ionic solid
E.
Network covalent solid
--------------------------------------------------------------------------------------------------------------7.
When two atoms of 2H are fused to form one atom of 4He, the total energy evolved
is 3.83 × 10–12 J. What is the total change in mass for this reaction?
A.
1.28 × 10–17 g
B.
4.26 × 10–26 g
C.
3.45 × 108 g
D.
1.15 g
E.
There is insufficient information to answer this question.
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--------------------------------------------------------------------------------------------------------------55
8.
Mn can be prepared by electron capture from
A.
55
Cr
B.
55
Fe
C.
56
Mn
D.
56
V
E.
56
Fe
--------------------------------------------------------------------------------------------------------------9.
Which of these orbitals is the result of adding two p-orbitals (i.e., a molecular
orbital that is the result of CONSTRUCTIVE interference of p-orbitals)?
A.
B.
C.
D.
E.
-----------------------------------------------------------------------------------------------------------10.
What is the oxidation number of manganese in the MnO4− ion?
A.
+1
B.
+2
C.
+4
D.
+5
E.
+7
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--------------------------------------------------------------------------------------------------------------11.
A reaction was studied as a function of temperature and the data shown was
obtained. The slope of the plot is −3.0 × 104 K. What is the activation energy for this
reaction?
A.
25 kJ/mole
B.
30 kJ/mole
C.
50 kJ/mol
D.
175 kJ/mol
E.
250 kJ/mol
ln k
1/T (K-1)
---------------------------------------------------------------------------------------------------------12.
How many electrons are transferred in the balanced half-reaction in which chlorine
gas is reduced to the aqueous chloride ion?
A.
one-electron
B.
two-electron
C.
four-electron
D.
three-electron
E.
six-electron
--------------------------------------------------------------------------------------------------------------13.
Which transformation could take place at the anode of an electrochemical cell?
A.
Cr3+(aq) to Cr2O72–(aq)
B.
F2(g) to F–(aq)
C.
O2(g) to H2O()
D.
HAsO2(aq) to As(s)
E.
Na+ (aq) to Na (s)
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--------------------------------------------------------------------------------------------------------------voltmeter
wire
Salt Bridge
Ag
1M Ag+
14.
Zn
1M Zn2+
What is E° for the cell shown above?
A.
0.04 V
B.
1.56 V
C.
0.96 V
D.
–0.04 V
E.
2.36 V
--------------------------------------------------------------------------------------------------------------15.
Which one of the following statements is true about the equilibrium constant for a
reaction if ΔG° for the reaction is negative?
A.
K=0
B.
K=1
C.
K>1
D.
K<1
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-----------------------------------------------------------------------------------------------------------16.
Which one of the following processes is/are spontaneous at 25°C?
i)
ii)
iii)
A.
B.
C.
D.
E.
dissolving sodium chloride in water
freezing water to form ice
mixing of two gases into one container
i
ii
iii
i and ii
i and iii
--------------------------------------------------------------------------------------------------------------17.
The solubility of manganese (II) hydroxide (Mn(OH)2) is 2.2 × 10−5 M. What is the
Ksp of Mn(OH)2?
A.
1.1 × 10−14
B.
4.3 × 10−14
C.
2.1 × 10−14
D.
4.8 × 10−10
E.
2.2 × 10−5
--------------------------------------------------------------------------------------------------------------18.
What current is required to plate out 1.28 g of nickel from a solution of Ni2+ in 1.0
hour?
A.
65.4 amps
B.
4.01 × 103 amps
C.
1.17 amps
D.
12.9 amps
E.
53.6 amps
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--------------------------------------------------------------------------------------------------------------19.
Which of the following aqueous solutions will have the same concentration of ions
as a 0.1M solution of MgCl2 ?
A.
0.1 M [Fe(H2O)6]Cl3
B.
0.1M K3[Co(CN)6]
C.
0.1M Na3[CoBr6]
D.
0.1 M Na4[CoF6]
E.
0.1 M [Ni(NH3)4]Br2
--------------------------------------------------------------------------------------------------------------20.
Which of the following cannot form both high- and low-spin octahedral complexes?
A.
B.
C.
D.
E.
Mn2+
V2+
Co3+
Cr2+
All of the above can form both high- and low-spin complexes.
--------------------------------------------------------------------------------------------------------------21.
[Ni(OH2)6]2+ is green, while [Ni(NH3)6]2+ is purple. Which of the following
statements is incorrect?
A.
B.
C.
D.
E.
The splitting parameter, Δ, is smaller for [Ni(OH2)6]2+ than it is for [Ni(NH3)6]2+.
[Ni(NH3)6]2+ absorbs violet light.
[Ni(OH2)6]2+ absorbs red light.
[Ni(OH2)6]2+ will absorb light of smaller energy than [Ni(NH3)6]2+.
The oxidation state of nickel is +2 for both complexes.
-----------------------------------------------------------------------------------------------------------22.
In the following reaction, Ni2+ is acting as a(n)
Ni2+ (aq) + 6H2O () → Ni(H2O)62+ (aq)
A.
oxidizing agent
B.
Lewis acid
C.
precipitating agent
D.
solvent
E.
insulator
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--------------------------------------------------------------------------------------------------------------23. Which one of the following melting point (mp) comparisons is incorrect?
A.
mp of Ar(s) > mp of Xe(s)
B.
mp of MgO(s) > mp of NaCl(s)
C.
mp of SiO2(s) > mp of SO2(s)
D.
mp of C(s) > mp of Hg(s)
E.
mp of H2O (s) > mp of N2(s)
--------------------------------------------------------------------------------------------------------------24.
Below is a piece of a polymer. What is the structure of the monomer for this
polymer?
H
H
*
H
H
C
C
A.
H
H
C
C.
C
Cl
Cl
*
H
H
Cl
Cl
H
H
C
C
H
Cl
H
H
C
C
H
Cl
D.
H
C
Cl
H
C
C
H
B.
H
H
E.
C
C
H
C
H
C
H
H
H
C
H
Cl
H
H
Cl
C
C
H
H
C
H
H
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--------------------------------------------------------------------------------------------------------------25.
An aluminum antimonide (AlSb) laser emits light with a wavelength of 730 nm.
What is the band gap of this semiconductor?
A.
2.72 × 10−19 J
B.
8.18 × 10−20 J
C.
2.43 × 10−15 J
D.
2.43 × 10−19 J
E.
2.19 × 10−19 J
--------------------------------------------------------------------------------------------------------------26.
Which of the following will form a basic solution?
A.
HF(aq)
B.
HCl(aq)
C.
NaCl(aq)
D.
NaOClO3(aq)
E.
NaOCl
--------------------------------------------------------------------------------------------------------------27. The half-life of 137Cs, which undergoes beta decay, is 30 years. How many years
must pass to reduce a 25 mg sample to 0.78 mg?
A.
60 years
B.
150 years
C.
180 years
D.
750 years
E.
5 years
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--------------------------------------------------------------------------------------------------------------28.
What are the spectator ions in the solution after completely precipitating an
insoluble sulfide compound when mixing FeCl3 (aq) and K2S (aq)?
A.
Fe3+ , Cl−, K+ , and S2−
B.
S2− and Fe3+
C.
K+ and Cl−
D.
K+ and Fe3+
E.
Cl−
--------------------------------------------------------------------------------------------------------------29.
Two substances A and B react with each other such that 50% of A is consumed in
33 minutes and 75% of A is consumed after a total of 66 minutes. Changing the
concentration of B has no effect on the reaction rate. The reaction of A with B is:
A.
zero order in both A and B.
B.
first order in both A and B.
C.
second order in both A and B.
D.
first order in A and zero order in B.
E.
second order in A and zero order in B.
--------------------------------------------------------------------------------------------------------------30.
In studying the rate of a decomposition reaction, the data shown in the graph were
obtained. The slope of the plot is −2.2 × 10−2 s−1. If the initial concentration of the
reactant, A, was 0.25M, which of the following statements are true?
i.
The rate law for this reaction can be written: rate = k[A].
ii.
The rate constant for this reaction is 2.2 × 10−2 s−1.
iii.
The y-intercept is 4 M−1.
A.
i only
B.
ii only
C.
iii only
D.
i and ii
E.
i and iii
ln[A]
t(sec)
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-----------------------------------------------------------------------------------------------------------31.
The decomposition of acetaldehyde, CH3CHO, can be catalyzed by I2 (g).
uncatalyzed reaction: Ea = 190 kJ/mol
CH3CHO (g) → CH4 (g) + CO (g)
catalyzed reaction: Ea = 136 kJ/mol
CH3CHO (g) + I2 (g) → CH3I (g) + HI (g) + CO (g)
CH3I (g) + HI (g)
→ CH4 (g) + I2 (g)
The following enthalpies of formation are also given:
molecule
ΔHf°
CH3CHO (g) –166 kJ/mol
CH4 (g)
–74.9 kJ/mol
CO (g)
–110.5 kJ/mol
Which of the following reaction profiles is most appropriate for the catalyzed and
uncatalyzed reactions? (The dotted lines are only a guide for your eye.)
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--------------------------------------------------------------------------------------------------------------32.
What is the pH of a solution made from 200 mL of 0.2 M NaOH and 50 mL of 0.2
M HCl?
A.
0.92
B.
1.40
C.
7.00
D.
12.5
E.
13.1
--------------------------------------------------------------------------------------------------------------33.
Calculate the value of ΔG° for this reaction at 25.0 °C.
N2 (g) + 3H2 (g)
A.
21.6 kJ/mol
B.
49.6 × 10−3 kJ/mol
C.
–4.16 kJ/mol
D.
–24.8 kJ/mol
E.
–49.6 kJ/mol
2NH3 (g)
K = 5.00 × 108
--------------------------------------------------------------------------------------------------------------34.
Which one of the following when added to a saturated solution of CaF2 will not
change the solubility of CaF2 in the solution?
A.
HF
B.
NaOH
C.
Ca(NO3)2
D.
NH3
E.
KCl
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--------------------------------------------------------------------------------------------------------------35.
AgCl is a sparingly soluble salt, with a solubility of about 10–5 M in pure water.
Adding KCN increases the solubility of AgCl because:
A.
B.
C.
D.
E.
CN– reacts with Ag+ to make a soluble complex.
CN– is a base, which increases the pH to form soluble AgOH.
K+ reacts with Cl– to form solid KCl.
CN– reduces Ag+ to Ag metal.
CN– reacts with Ag+ to make a sparingly soluble salt with a larger Ksp than
AgCl.
--------------------------------------------------------------------------------------------------------------36.
What is Ka of a weak acid HX if a mixture of 50 mL of 0.1 M HX and 20 mL of 0.1
M NaOH produce a solution with a pH of 3.5?
A.
1.3 × 10–4
B.
7.9 × 10–4
C.
3.2 × 10–4
D.
2.1 × 10–4
E.
4.7 ×10–4
--------------------------------------------------------------------------------------------------------------37.
Given an aqueous solution containing 1M of each of the following: Fe+3 (aq), Zn+2
(aq), Ni+2 (aq), and Cu+2 (aq), what product will form at the cathode when a current
is passed through the electrolytic cell?
A.
Fe+2 (aq)
B.
Ni (s)
C.
Cu (s)
D.
Fe (s)
E.
Zn (s)
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--------------------------------------------------------------------------------------------------------------38.
What is the pH of a 0.025 M solution of NH4Cl?
Kb of NH3 is 1.8 × 10–5
A.
8.6
B.
3.8
C.
9.3
D.
5.4
E.
3.2
--------------------------------------------------------------------------------------------------------------Answer the next 2 questions using the following information:
HCN (aq)
H+ (aq) + CN– (aq)
Kc = 4.9 × 10–10
39.
Which of the following statements are true?
1.
2.
3.
40.
HCN is a weak electrolyte.
Equilibrium lies to the right so formation of products is favored.
Addition of HCN will decrease the value of Kc.
A.
2 only
B.
2 and 3 only
C.
1 and 3 only
D.
1 only
E.
None of these are true.
------------------------------------------------------------------What is the value of Kc for the reaction.
CN– (aq) + H+ (aq)
A.
2.45 × 10–10
B.
2.0 × 109
C.
2.0 × 10–5
D.
4.9 × 10–10
E.
4.9 × 104
HCN (aq)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------END OF EXAM
Chem 112 Summer 2012
Final Exam Answer Key
6/25/12
Form A
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
E
C
B
E
C
E
B
B
E
E
E
B
A
B
C
E
B
C
E
B
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
B
B
A
B
A
E
B
C
D
D
A
E
E
E
A
D
A
D
D
B