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1. Chlorine dioxide reacts in basic water to form chlorite and chlorate according to the
following chemical equation:
2ClO2(aq) + 2OH–(aq)  ClO2–(aq) + ClO3–(aq) + H2O(l)
Under a certain set of conditions, the initial rate of disappearance of chlorine dioxide
was determined to be 2.30 x 10–1 M/s. What is the initial rate of appearance of chlorite
ion under those same conditions?
A) 5.75 x 10–2 M/s
B) 1.15 x 10–1 M/s
C) 2.30 x 10–1 M/s
D) 4.60 x 10–1 M/s
E) 9.20 x 10–1 M/s
2. For the reaction C6H14(g)  C6H6(g) + 4H2(g), P(H2)/t was found to be 2.5 × 10–2
atm/s, where P(H2) is the change in pressure of hydrogen. Determine P(C6H14)/t
for this reaction at the same time.
A) 2.5 × 10–2 atm/s
B) –6.2 × 10–3 atm/s
C) –2.5 × 10–2 atm/s
D) 0.10 atm/s
E) 6.2 × 10–3 atm/s
3. The reaction A + 2B  products has the rate law, rate = k[A][B]3. If the concentration
of B is doubled while that of A is unchanged, by what factor will the rate of reaction
increase?
A) 2
B) 4
C) 6
D) 8
E) 9
4. For the overall chemical reaction shown below, which one of the following statements
can be rightly assumed?
2H2S(g) + O2(g)  2S(s) + 2H2O(l)
A) The reaction is third-order overall.
B) The reaction is second-order overall.
C) The rate law is, rate = k[H2S]2 [O2].
D) The rate law is, rate = k[H2S] [O2].
E) The rate law cannot be determined from the information given.
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5. The reaction A + 2B  products was found to have the rate law, rate = k[A] [B]2.
Predict by what factor the rate of reaction will increase when the concentration of A is
doubled and the concentration of B is also doubled.
A) 2
B) 4
C) 6
D) 8
E) 9
6. It takes 42.0 min for the concentration of a reactant in a first-order reaction to drop from
0.45 M to 0.32 M at 25°C. How long will it take for the reaction to be 90% complete?
A) 13.0 min
B) 86.0 min
C) 137 min
D) 222 min
E) 284 min
7. Nitric oxide gas (NO) reacts with chlorine gas according to the chemical equation given
below.
1
NO + 2 Cl2  NOCl
The following initial rates of reaction have been measured for the given reagent
concentrations.
Expt. #
Rate (M/hr)
NO (M)
Cl2 (M)
1
1.19
0.50
0.50
2
4.79
1.00
0.50
3
9.59
1.00
1.00
Which of the following is the rate law (rate equation) for this reaction?
A) rate = k[NO]
B) rate = k[NO][Cl2]1/2
C) rate = k[NO][Cl2]
D) rate = k[NO]2[Cl2]
E) rate = k[NO]2[Cl2]2
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8. Use the following data to determine the rate law for the reaction shown below.
2NO + H2  N2O + H2O
Expt. #
[NO]0
[H2]0
Initial rate
1
0.021
0.065
1.46 M/min
2
0.021
0.260
1.46 M/min
3
0.042
0.065
5.84 M/min
A) rate = k[NO]
B) rate = k[NO]2
C) rate = k[NO][H2]
D) rate = k[NO]2[H2]
E) rate = k[NO]2[H2]2
9. The half life for a first order reaction is 45 min. What is the rate constant in units of s-1?
A) 0.015 s-1
B) 65 s-1
C) 2.6 x 10-4 s-1
D) 3.9 x 103 s-1
E) 1.9 x 103 s-1
10. The first-order decomposition, A  products, has a rate constant of 0.150 s–1. Starting
with [A]o = 0.350 M, how much time is required for [A]t = 0.125 M?
A) 6.86 s
B) 2.98 s
C) 34 s
D) 1.50 s
E) 4.62 s
11. Appropriate units for a second-order rate constant are
A) M/s
B) 1/M·s
C) 1/s
D) 1/M2·s
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12. The isomerization of cyclopropane to form propene is a first-order reaction.
At 760 K, 15% of a sample of cyclopropane changes to propene in 6.8 min. What is the
half-life of cyclopropane at 760 K?
A) 3.4 × 10–2 min
B) 2.5 min
C) 23 min
D) 29 min
E) 230 min
13. At 700 K, the rate constant for the following reaction is 6.2 × 10–4 min–1.
How many minutes are required for 20% of a sample of cyclopropane to isomerize to
propene?
A) 1,120 min
B) 360 min
C) 3710 min
D) 1.4 × 10–4 min
E) 280 min
14. A reaction was experimentally determined to follow the rate law, Rate = k[A]2 where k
= 0.456 s-1M-1. Starting with [A]o = 0.500 M, how many seconds will it take for [A]t =
0.250 M?
A) 2.85 x 10-2 s
B) 1.14 x 10-1 s
C) 1.52 s
D) 4.39 s
E) 5.48x10-1 s
15. A reaction is experimentally found to follow the rate law, Rate = k[A]2 where k = 0.355
M-1min-1. Starting with [A]o = 1.55 M, how many seconds will it take for [A]t =
0.150M
A) 6.58 s
B) 395 s
C) 6.02 s
D) 17.0 s
E) 1.02 x 103 s
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16. The thermal decomposition of acetaldehyde, CH3CHO  CH4 + CO, is a second-order
reaction. The following data were obtained at 518°C.
time, s
Pressure CH3CHO, mmHg
0
364
42
330
105
290
720
132
Based on the data given, what is the half-life for the disappearance of acetaldehyde?
A) 1.5 × 105 s
B) 410 s
C) 5.4 × 107 s
D) 520 s
E) 305 s
17. The graphs below all refer to the same reaction. What is the order of this reaction?
A)
B)
C)
D)
zero order
first order
second order
unable to predict
18. For what order reaction does the half-life get longer as the initial concentration
increases?
A) zero order
B) first order
C) second order
D) none of them because half-life is always independent of the initial concentration
19. Which one of the following changes would alter the rate constant (k) for the reaction 2A
+ B  products?
A) increasing the concentration of A
B) increasing the concentration of B
C) increasing the temperature
D) measuring k again after the reaction has run for a while
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20. The Arrhenius equation is k = Ae–Ea/RT. The slope of a plot of ln k vs. 1/T is equal to
A) –k
B) k
C) Ea
D) –Ea /R
E) A
21. What is the slope of an Arrhenius plot for the following reaction?
2NOCl  2NO + Cl2
Temperature (K)
k (L/mol·s)
400.
6.6 × 10–4
500.
2.9 × 10–1
600.
16.3
–2
A) 8.18 × 10 K
B) 5.06 × 10–2 K
C) –1.22 × 104 K
D) –1.96 × 104 K
E) not enough information to calculate the slope
22. The isomerization of cyclopropane follows first order kinetics. The rate constant at 700
K is 6.20 × 10–4 min–1, and the half-life at 760 K is 29.0 min. Calculate the activation
energy for this reaction.
A) 5.07 kJ/mol
B) 27.0 kJ/mol
C) 50.7 kJ/mol
D) 60. kJ/mol
E) 270. kJ/mol
23. The reaction C4H10  C2H6 + C2H4 has an activation energy (Ea) of 350 kJ/mol, and the
Ea of the reverse reaction is 260 kJ/mol. Estimate H, in kJ/mol, for the reaction as
written above.
A) –90 kJ/mol
B) +90 kJ/mol
C) 350 kJ/mol
D) –610 kJ/mol
E) +610 kJ/mol
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24. Given that Ea for a certain biological reaction is 48 kJ/mol and that the rate constant is
2.5 × 10–2 s–1 at 15°C, what is the rate constant at 37°C?
A) 2.7 × 10–2 s–1
B) 2.5 × 10–1 s–1
C) 1.0 × 10–1 s–1
D) 6.0 × 10–3 s–1
E) 1.1 s–1
25. For the chemical reaction system described by the diagram below, which statement is
true?
A) The forward reaction is endothermic.
B) The activation energy for the forward reaction is greater than the activation energy
for the reverse reaction.
C) At equilibrium, the activation energy for the forward reaction is equal to the
activation energy for the reverse reaction.
D) The activation energy for the reverse reaction is greater than the activation energy
for the forward reaction.
E) The reverse reaction is exothermic.
26. The rate law for the reaction 2NO2 + O3  N2O5 + O2 is rate = k[NO2][O3]. Which
one of the following mechanisms is consistent with this rate law?
A) NO2 + NO2  N2O4
(fast)
N2O4 + O3  N2O5 + O2 (slow)
B) NO2 + O3  NO5
(fast)
5
NO5 + NO5  N2O5 + /2O2 (slow)
C) NO2 + O3  NO3 + O2 (slow)
NO3 + NO2  N2O5
(fast)
D) NO2 + NO2  N2O2 + O2 (slow)
N2O2 + O3  N2O5
(fast)
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27. The peroxodisulfate ion can oxidize iodide ions to iodine according to the balanced
equation
S2O82– + 2I –  2SO42– + I2.
The reaction is catalyzed by certain chemical species. Identify the catalyst in the
following mechanism:
step 1:
Fe3+ + 2I –  Fe2+ + I2
step 2:
S2O82– + Fe2+  2SO42– + Fe3+
A) Fe3+
B) I –
C) S2O82–
D) Fe2+
E) SO42–
28. At a particular temperature the first-order gas-phase reaction N2O5  2NO2 + 1/2O2 has
a half-life for the disappearance of dinitrogen pentoxide of 5130 s. Suppose 0.450 atm
of N2O5 is introduced into an evacuated 2.00 L flask. What will be the total gas
pressure inside the flask after 3.00 hours?
A) 0.969 atm
B) 0.105 atm
C) 0.795 atm
D) 1.14 atm
E) 0.864 atm
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Answer Key
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B
B
D
E
D
E
D
B
C
A
B
D
B
D
E
B
A
A
C
D
C
E
B
C
D
C
A
A
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