Name ______________________________
ID#_______________________
Section # ________
CH 1020 EXAM 1 Spring 2016 - Form A
Fill in your name, ID#, and section on this test booklet. Fill in and bubble in your name, ID# (bubble 0 for “C”),
and section on the scantron form. For question #60 mark A. Mark the best answer after reading all possible
choices. Use a #2 pencil and make clean erasures to insure proper scoring. When finished, turn in your scantron
sheet and show this booklet and your CUID to the proctor. All questions are worth 4 points.
1. Given the following spontaneous chemical reaction
in gaseous state, what are the signs of ∆H, ∆S and
∆G?
4. Calculate ∆G⁰rxn for the following reaction using
the following information:
4 HNO3(g) + 5 N2H4(l) → 7 N2(g) + 12 H2O(l)
Compound
HNO3(g)
N2H4(l)
H2O(l)
A.
B.
C.
D.
E.
∆H
+
−
+
−
+
∆S
+
−
+
+
−
∆G
+
−
−
−
+
A. −954.7 kJ
B. +110.7 kJ
C. −312.9 kJ
∆G⁰f (kJ/mol)
−73.5
+149.3
−237.1
D. +2.845  103 kJ
E. −3.298  103 kJ
5. Consider the reaction of hydrogen and nitric oxide
which has the rate law: rate = k[H2][NO]2.
2H2(g) + 2NO(g)  2H2O(g) + N2(g)
2. The solution of CaCl2 in water has a negative
∆Hsoln. Which of the following statements is
correct?
The following pictures represent different mixtures
of reactant gases. Which would have the fastest
initial rate?
A. ∆Hsolute-solvent is larger in magnitude than
∆Hsolute-solute plus ∆Hsolvent-solvent.
B. ∆Hsolute-solvent is larger in magnitude than
Hsolute-solute but smaller than ∆Hsolvent-solvent.
C. ∆Hsolute-solvent is smaller in magnitude than
Hsolute-solute plus ∆Hsolvent-solvent.
D. ∆Hsolute-solvent is smaller in magnitude than
Hsolute-solute but larger than ∆Hsolvent-solvent.
3. Gallium-67 is a radioactive isotope that is used in
medical imaging. Its radioactive decay follows
first order kinetics and its half-life is 3.26 days.
What is the rate constant for the radioactive decay
of this isotope if it is in solution at a concentration
of 1.00 M solution?
A. 0.0923 d1
B. 0.153 d1
C. 0.213 d1
D. 0.307 d1
E. 4.70 d1
Trial 1
A.
B.
C.
D.
Trial 2
Trial 3
Trial 1
Trial 2
Trial 3
They would all have the same initial rate.
6. An aqueous solution has a concentration of
0.0480 m LiF. What is the molarity of solution if
the density is 1.10 g/mL?
A. 0.0436 M
B. 0.0480 M
C. 0.0441 M
D. 0.0528 M
Page 1 of 4
7. Three liquids of equal volume are allowed to
evaporate for some time. Rank the beakers by
decreasing liquid level. (The beaker from which
the least solvent evaporated should be first.) The
solutes do not dissociate on dissolving.
Liquid A: pure water
Liquid B: aqueous solution of nicotine
Liquid C: aqueous solution of caffeine and
sucrose
9. The decomposition of hydrogen peroxide occurs
according to the equation:
2H2O2(aq) → 2H2O(l) + O2(g)
and has the rate law rate = (0.065 h1)[H2O2].
A plot of which of the following is a straight line?
A. [H2O2] versus time
B. ln [H2O2] versus time
1
versus time
[H 2O2 ]
1
D. [H2O2] versus
time
1
E. ln [H2O2] versus
time
C.
nicotine, C10H14N2
sucrose, C12H22O11
caffeine, C8H10N4O2
A
B
10. Sodium hydroxide (NaOH) is a strong base used in
cleaning agents. Dissolving NaOH in water will
increase the temperature of the solution. Which
statement is correct regarding ∆Hsoln and ∆Ssoln?
C
greatest volume → least volume remaining
A. ∆Hsoln is positive and ∆Ssoln is negative
A. A > B > C
B. ∆Hsoln is positive and ∆Ssoln is positive
B. B > C > A
C. ∆Hsoln is negative and ∆Ssoln is negative
C. C > A > B
D. ∆Hsoln is negative and ∆Ssoln is positive
D. B > A > C
E. We cannot know
E. C > B > A
8. Which statement is correct for the decomposition
of nitric oxide, NO?
2NO(g) → N2(g) + O2(g)
Hf (kJmol1)
S (JK1mol1)
NO(g)
90
211
N2(g)
0
192
O2(g)
0
201
A. The reaction is spontaneous at all
temperatures.
B. The reaction is not spontaneous at any
temperature.
C. The reaction is spontaneous only at high
temperatures.
D. The reaction is spontaneous only at low
temperatures.
11. From each pair choose the substance with the
highest molar entropy at 298 K.
Set I:
O3(g) or O2(g)
Set II: H2O(g) or H2O(l)
A.
B.
C.
D.
Set I
O3(g)
O3(g)
O2(g)
O2(g)
Set II
H2O(g)
H2O(l)
H2O(g)
H2O(l)
12. Which 0.020 m solution containing the following
solutes has the largest ideal van’t Hoff factor?
A. C6H12O6
B. Na2SO4
C. KNO3
D. K3PO4
E. CH3COOH
Page 2 of 4
13. What is the rate law for the reaction of X, Y and
Z?
Exp. 1
Exp. 2
rate = 1
rate = 2
Exp. 3
rate = 4
Exp. 4
rate = 1
A. rate = [X][Y][Z]
17. A certain substance undergoes second order
decomposition. For a 0.036 M initial
concentration the rate of decomposition is
1.4  103 M/min. If the initial concentration is
increased to 0.048 M, what would be the rate of
decomposition?
A.
B.
C.
D.
E.
1.1 M/min
5.2  102 M/min
9.0 103 M/min
2.5  103 M/min
1.9  103 M/min
B. rate = [X][Y]2[Z]4
18. Rank the following compounds by increasing
thermodynamic stability with respect to their
constituent elements at 25°C.
C. rate = [X][Y][Z]2
D. rate = [Z]2
E. rate = [Y][Z]2
14. For the combustion of propane, predict the signs of
the entropy change for the system, surroundings,
and the universe.
C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g) + heat
A.
B.
C.
D.
E.
Ssystem
+

+

+
Ssurroundings
+


+
+
Suniverse
+

+ or 
+ or 

15. Which of the following solvents is the best for
dissolving methylamine, CH3NH2?
A.
B.
C.
D.
pentane, CH3CH2CH2CH2CH3
ethanol, CH3CH2OH
benzene, C6H6
carbon tetrachloride, CCl4
16. A scientist conducts an experiment to determine
the rate of the following reaction:
Compound
I
II
III
Species
H2Se (g)
H2O (g)
H2S (g)
ΔG˚f (kJ/mol)
+15.9
−228.6
−33.6
least stable → most stable
A. H2Se < H2O < H2S
B. H2S < H2Se < H2O
C. H2O < H2S < H2Se
D. H2S < H2O < H2Se
E. H2Se < H2S < H2O
19. A 15.0 mg sample of a protein was dissolved in
water to produce 5.00 mL of solution at 25.1 C.
The osmotic pressure of this solution was
measured and found to be 6.50 torr. What is the
molar mass of this protein assuming it does not
ionize?
A. 427 g/mol
B. 941 g/mol
C. 8580 g/mol
D. 4270 g/mol
E. 561 g/mol
N2 (g) + O2 (g)  2 NO(g)
If the initial concentration of N2 was 0.500 M and
the concentration of N2 was 0.450 M after 0.100 s,
what is the average rate of reaction over the first
0.100 seconds?
A. 0.50 M/s
B. 1.0 M/s
C. 5.0 M/s
D. 10. M/s
E. 0.25 M/s
Page 3 of 4
20. If the rate of concentration change of ammonia,
NH3, is 0.345 M/s, what is the rate of concentration
change of N2?
N2(g) + 3 H2 (g)  2 NH3 (g)
A. 0.173 M/s
B. 0.345 M/s
C. 0.690 M/s
24. A solution of 5.00 g of sodium chloride in 1.00 kg
of water has a freezing point of –0.299 C. What is
the actual van’t Hoff factor for this salt at this
concentration compared to the ideal one of 2.0?
A. 1.88
B. 1.98
C. 1.93
D. 0.173 M/s
E. 0.345 M/s
21. A solution is saturated in both carbon dioxide gas
and calcium chloride at 50 C. When the solution
is cooled to 10 C, which of the following is most
likely to occur?
A. Some carbon dioxide gas bubbles out of
solution.
B. Some calcium chloride precipitates from
solution.
C. Some carbon dioxide gas bubbles out of
solution and some calcium chloride
precipitates from solution.
D. Nothing happens.
25. The first order decomposition of N2O at 1000 K
has a rate constant of 0.76 s1. If the initial
concentration of N2O is 10.9 M, what is the
concentration of N2O remaining after 9.6 s?
A. 7.4  103 M
B. 1.0  103 M
C. 1.4  103 M
2 HgO(s) → 2 Hg(l) + O2(g)
Determine the temperature range over which the
reaction will proceed as written. Assume that
Hrx = 182 kJ and Srx = 216 J/K.
A.
B.
C.
D.
CaCO3(s) → CaO(s) + CO2(g)
G is more positive than H.
G is less positive than H.
G is equal to H.
S is negative.
H is negative.
23. Conveniently, benzene (C6H6) has a vapor pressure
of 100.0 mmHg at 26.0 ºC. A nonvolatile
molecular compound was added to 0.300 mol of
benzene at 26.0 ºC and the vapor pressure
decreased to 60.0 mmHg. How many moles of the
nonvolatile compound were added?
A. 0.100 moles
B. 0.200 moles
D. 3.6  103 M
E. 8.7  103 M
26. Elemental mercury can be produced from its oxide.
22. Which of the statements regarding the following
endothermic reaction is true?
A.
B.
C.
D.
E.
D. 1.83
E. 1.94
60.
at all temperature
T < 842 K
T > 842 K
at no temperature
Mark A on your scantron
C. 0.300 moles
D. 0.400 moles
Page 4 of 4
USEFUL INFORMATION:
H system
G = H  TS
Ssurroundings = -
Ho = npHof (products) - nrHof (reactants)
So = npSo (products) - nrSo (reactants)
T
Go = npGof (products) - nrGof (reactants)
Tb = i Kb  m
For water: Kb = 0.51 C/m
Tf = i  Kf  m
For water: Kf = 1.86 C/m
Psoln = Xsolvent  Psolvent
=iMRT
760 torr = 1 atm
R = 8.314 J/K·mol = 0.08206 L·atm/ K·mol
[A]t = kt + [A]0
t½ =
[A]0
2k
ln [A]t = kt + ln[A]0
t½ =
ln 2
k
S = kH  P
1/[A]t = kt + 1/[A]0
t½ =
1
[A]0 • k