Princeton 2012/Barron 4th ed.
AP Practice Problems
Unit 10 – Kinetics
Multiple Choice (no calculator)
For questions 1-3, one or more of the
following responses will apply; each
response may be used more than once or not
at all in these questions.
A+BC
The following are possible rate laws for the
hypothetical reaction given above.
A.
B.
C.
D.
E.
Rate = k[A]
Rate = k[A]2
Rate = k[A][B]
Rate = k[A] 2[B]
Rate = k[A] 2[B] 2
4. When [A] and [B] are doubled, the
initial rate of reaction will increase
by a factor of eight. (P12.4)
5. When [A] and [B] are doubled, the
initial rate of reaction will increase
by a factor of two. (P12.5)
6. When [A] is doubled and [B] is held
constant, the initial rate of reaction
will not change. (P12.6)
7. A multi-step reaction takes place by
the following mechanism:
A+BC+D
A+CD+E
1. This is the rate law for a first order
reaction. (P12.1)
2. This is the rate law for a reaction that
is second order with respect to B.
(P12.2)
3. This is the rate law for a third order
reaction. (P12.3)
For questions 4-6, one or more of the
following responses will apply; each
response may be used more than once or not
at all in these questions.
A+BC
The following are possible rate laws for the
hypothetical reaction given above.
A.
B.
C.
D.
E.
Rate = k[A]
Rate = k[B]2
Rate = k[A][B]
Rate = k[A] 2[B]
Rate = k[A] 2[B] 2
Which of the species shown above is
an intermediate in the reaction?
(P12.7)
a.
b.
c.
d.
e.
A
B
C
D
E
Princeton 2012/Barron 4th ed.
8. The reaction below takes place with
all of the reactants and products in
the gaseous phase. Which of the
following is true of the relative rates
of disappearance of the reactants and
appearance of the products? (P12.8)
When the reaction given above takes
place, the rate law is
Rate = k[A]
2NOCl  2NO + Cl2
If the temperature of the reaction
chamber were increased, which of
the following would be true?
(P12.10)
a. NO appears twice at the rate
that NOCl disappears.
b. NO appears at the same rate
the NOCl disappears
c. NO appears at half the rate
that NOCl disappears
d. Cl2 appears at the same rate
that NOCl disappears
e. Cl2 appears at twice the rate
that NOCl disappears
9.
a. The rate of reaction and the
rate constant will increase
b. The rate of reaction and the
rate constant will not change
c. The rate of reaction will
increase and the rate constant
will decrease
d. The rate of reaction will
increase and the rate constant
will not change
e. The rate of reaction will not
change and the rate constant
will increase
H2(g) + I2(g)  2HI(g)
When the reaction given above takes
place in a sealed isothermal
container, the rate law is
Rate = k[H2][I2]
If a mole of H2 gas is added to the
reaction chamber, which of the
following will be true? (P12.9)
a. The rate of reaction and the
rate constant will increase
b. The rate of reaction and the
rate constant will not change
c. The rate of reaction will
increase and the rate constant
will decrease
d. The rate of reaction will
increase and the rate constant
will not change
e. The rate of reaction will not
change and the rate constant
will increase
A+BC
10.
A+BC
11.
Based on the following experimental
data, what is the rate law for the
hypothetical reaction given above?
(P12.11)
Experiment
[A]
(M)
[B]
(M)
1
2
3
0.20
0.20
0.40
0.10
0.20
0.20
a.
b.
c.
d.
e.
Rate = k[A]
Rate = k[A]2
Rate = k[B]
Rate = k[B]2
Rate = k[A][B]
Initial Rate
of
Formation
of C
(mol/L-sec)
3×10-2
6×10-2
6×10-2
Princeton 2012/Barron 4th ed.
A+BC+D
12.
The rate law for the hypothetical
reaction shown above is as follows:
Rate = k[A]
Which of the following changes to
the system will increase the rate of
the reaction? (P12.12)
I. An increase in the
concentration of A
II. An increase in the
concentration of B
III. An increase in the
temperature
a.
b.
c.
d.
e.
I only
I and II only
I and III only
II and III only
I, II, and III
A+BC
13.
Based on the following experimental
data, what is the rate law for the
hypothetical reaction given above?
(P12.13)
Experiment
[A]
(M)
[B]
(M)
1
2
3
0.20
0.20
0.40
0.10
0.20
0.40
a.
b.
c.
d.
e.
Rate = k[A]
Rate = k[A]2
Rate = k[B]
Rate = k[B]2
Rate = k[A][B]
A+BC
14.
Initial Rate
of
Formation
of C
(mol/L-sec)
2.0×10-6
4.0×10-6
1.6×10-5
Based on the following experimental
data, what is the rate law for the
hypothetical reaction given above?
(P12.14)
Experiment
[A]
(M)
[B]
(M)
1
2
3
0.10
0.40
0.40
0.10
0.10
0.20
a.
b.
c.
d.
e.
Initial Rate
of
Formation
of C
(mol/L-sec)
1.5×10-3
6.0×10-3
2.4×10-2
Rate = k[A]
Rate = k[A]2
Rate = k[A][B] 2
Rate = k[B]2
Rate = k[A]2[B] 2
15. Reactant A underwent a
decomposition reaction. The
concentration of A was measured
periodically and recorded in the chart
below. Based on the data in the
chart, which of the following is the
rate law for the reaction? (P12.15)
Time (hours)
0
1
2
3
a.
b.
c.
d.
e.
[A] M
0.40
0.20
0.10
0.05
Rate = k[A]
Rate = k[A]2
Rate = 2k[A]
Rate = ½k[A]
Rate = k
Princeton 2012/Barron 4th ed.
For the following responses below, one or
more of the following responses applies;
each response may be used more than once
or not at all in these questions.
I.
II.
III.
IV.
V.
Activation energy
Orientation
Potential energy curve
Frequency
Activated complex
16. The heat of a reaction is best
deduced from the (B11.1)
a.
b.
c.
d.
e.
f.
I
II
III
IV
IV
V
17. The collision theory involves
(B11.2)
a.
b.
c.
d.
e.
I and III
II
II and IV
IV
I, III, and V
18. The transition-state theory involves
(B11.3)
a.
b.
c.
d.
e.
I and III
III
III and V
IV
I, III, and V
19. The rate of a chemical reaction is
related to the (B11.4)
a.
b.
c.
d.
e.
I and III
II
I, II, and IV
IV
I, III, and V
20. The activated complex may be
described as (B11.5)
a. An elementary reaction in a
mechanism
b. The shape of the molecules at
the moment of collision
c. The shape of the reaction
product
d. The phase – liquid, solid, or
gas – in which a reaction
takes place
e. A coordination state
21. A reaction in which the rate and the
rate constant have the same units is
(B11.6)
a. A radioactive decay
b. A second-order reaction
c. A reaction with a one-step
mechanism
d. A first-order reaction
e. A zero-order reaction
Princeton 2012/Barron 4th ed.
Questions 22-24 refer to the following
diagram.
24. Addition of a catalyst to the reaction
mixture will affect only (B11.9)
a.
b.
c.
d.
e.
A
B
C
D
E
25. A fast reaction should have (B11.10)
22. In the reaction profile, A, B, and C
should be labeled as shown in
(B11.7)
a. A = potential energy, B =
reaction coordinate, C =
activation energy
b. A = heat of reaction, B =
reaction coordinate, C =
potential energy
c. A = potential energy, B =
reaction coordinate, C = heat
of reaction
d. A = heat of reaction, B =
potential energy, C =
activation energy
e. A = activation energy, B =
extent of reaction, C = heat of
reaction
23. In the reaction described by the
reaction profile, (B11.8)
a. Forward Ea > reverse Ea and
∆H is exothermic
b. Reverse Ea > forward Ea and
∆H is endothermic
c. Forward Ea < reverse Ea and
∆H is exothermic
d. Reverse Ea < forward Ea and
∆H is endothermic
e. Reverse Ea > forward Ea and
∆H is zero
a.
b.
c.
d.
e.
A high activation energy
A catalyst present
A large equilibrium constant
A low activation energy
An exothermic heat of
reaction
26. Which of the following rate laws has
a rate constant with units of L2mol-1s1
? (B11.11)
a.
b.
c.
d.
e.
Rate = k[A]
Rate = k[A]2
Rate = k[A][B]
Rate = k[A][B]2
Rate = k[A]0
27. Which of the following is LEAST
effective in increasing the rate of a
reaction? (B11.12)
a. Increasing the pressure by
adding an inert gas
b. Grinding a solid reactant into
small particles
c. Increasing the temperature
d. Eliminating reverse reactions
e. Adding a catalyst
Princeton 2012/Barron 4th ed.
28. If a reactant’s concentration is
doubled and the reaction rate
increases by a factor of 8, the
exponent for that reactant in the rate
law should be (B11.14)
a.
b.
c.
d.
e.
0
1
2
3
½
29. A graph of the reciprocal of reactant
concentration versus time will give a
straight line for (B11.16)
a.
b.
c.
d.
e.
A zero-order reaction
A first-order reaction
A second-order reaction
Both a and c
a, b, and c
30. Which of the following will be most
helpful in determining the stability or
shelf life of a new drug? (B11.18)
31. An Arrhenius plot is a graph of
(B11.19)
a. The rate constant versus
concentration
b. The natural logarithm (ln) or
the rate constant versus
concentration
c. The reciprocal of the rate
constant versus ln T
d. The rate constant versus ln
(1/T)
e. The natural logarithm (ln) of
the rate constant versus 1/T
32. A first-order reaction has a half-life
of 85 s. What fraction of the reactant
is left after 255 s? (B11.20)
a.
b.
c.
d.
e.
1/2
1/4
1/8
1/3
7/8
33. A rate law is found to be
a. The reaction mechanism for
its decomposition
b. The rate law for its
decomposition
c. The Arrhenius plot of the
decomposition reaction
d. The integrated rate law plot
e. The overall chemical reaction
Rate = k[A]2[B]
The order of the reaction is (B11.21)
a.
b.
c.
d.
e.
First order
Second order
Third order
Fourth order
The rate order cannot be
determined
Princeton 2012/Barron 4th ed.
34. A rate law is found to be
35. Modern automobiles use a catalytic
converter to (B11.24)
Rate = k[A]2[B]
Which of the following actions will
NOT change the initial reaction rate?
(B11.22)
a. Doubling the concentrations
of both A and B
b. Doubling the concentration
of A and halving the
concentration of B
c. Halving the concentration of
A and doubling the
concentration of B
d. Halving the concentration of
A and quadrupling the
concentration of B
e. Doubling the concentration
of A and quadrupling the
concentration of B
a. Increase the horsepower by
burning more gasoline
b. Absorb pollutants from the
exhaust
c. Complete the combustion of
unburned gases
d. Cool the exhaust gases
e. Convert pollutants into water
Princeton 2012/Barron 4th ed.
Answer Key – Kinetics
Multiple Choice
1. A
2. E
3. D
4. D
5. A
6. B
7. C
8. B
9. D
10. A
11. C
12. C
13. E
14. C
15. A
16. C
17. C
18. E
19. C
20. B
Essays
1. (a) Rate = k[A][B]
(b) k= 1.2 M-1s-1
(c) Rate = 4.8×10-4 M/s
(d) i = A + 2B  2C
ii = A + B  C + D (slow)
D + B  C (fast)
2. (a) Rate = k[NO]2[Br2]
(b) k = 1.2 ×10-4 M-2s-1
(c) 0.02 mol
(d) Choice I agrees with the rate law
3. (a) k = 0.0163 min-1
(b) 8.19 min
(c) 0.078 M
(d) 0.0652 M/min
(e) 42.5 min
4. (a) Rate = k[B]
(b) k = 1.5×10-2 min-1
(c) 0.1 M
(d) Choice I
(e) 46 min
5. (a) rate will increase; rate constant will not change
(b) rate will stay the same; rate constant will not change
(c) rate will increase; rate constant will increase
(d) neither rate nor rate constant is affected
(e) rate will increase; rate constant will not change
6. (a) line 2 is the catalyzed reaction
(b) line 2 shows higher temperature distribution
(c) line 1 is correct
(d) graph 1 is correct
(e) line 2 is correct
21. E
22. A
23. D
24. C
25. D
26. D
27. A
28. D
29. C
30. C
31. E
32. C
33. C
34. D
35. C
Princeton 2012/Barron 4th ed.
7. (a) Increase in temperature means an increase in energy of the molecules present. If the
molecules have more energy, then more of them will collide more often with enough
energy to overcome the activation energy, causing the reaction to proceed more quickly.
(b) A catalyst lowers the activation energy of the reaction.
(c) The effectiveness of a solid catalyst depends on the surface area of the catalyst that is
exposed to the reactants. Grinding a solid into powder greatly increases its surface area.
(d) Increasing the concentration of reactants crowds the reactants more closely together
making it more likely that they will collide with one another. The more collisions that
occur, the more likely that collisions will occur that result in reactions.