Chemistry
Raymond Chang
10th edition
Chapter 13
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Question 1
For the reaction 2A + B → C it is found that
changing the concentration of A has no
impact on the rate, but when B is doubled
the rate doubles. The rate law is
25%
25%
25%
2
3
25%
A) rate = k[A]2[B].
B) rate = k[A][B]2.
C) rate = k[B]2.
D) none of the above.
1
4
Question 2
If the activation energy of a reaction is
decreased, the reaction rate will increase.
A) True
B) False
50%
50%
1
2
Question 3
Which of the following is true?
20%
20%
A) A catalyst is not
consumed in the reaction.
B) A catalyst speeds up
the forward reaction.
C) A catalyst speeds
up the reverse reaction.
D) A catalyst
decreases the activation
energy.
E) All of the above.
1
2
20%
3
20%
4
20%
5
Question 5
Which of the following will cause the
reaction rate to increase?
20%
20%
20%
2
3
20%
20%
A) Increasing the
temperature.
B) Adding a catalyst.
C) Reducing the
concentration of reactants.
D) Both A and B.
E) Both B and C.
1
4
5
Question 6
Using the data below, determine the rate law
for the reaction of A with B to produce C.
Exp 1: 0.100 M A, 0.100 M B, rate 0.120 M/s
Exp 2: 0.100 M A, 0.200 M B, rate 0.120 M/s
Exp 3: 0.200 M A, 0.100 M B, rate 0.480 M/s
25%
25%
25%
2
3
25%
A) rate=k[A]2[B]
B) rate=k[A]2
C) rate=k[B]2
D) rate=k[A][B]
1
4
Question 8
If a proposed mechanism is consistent
with the experimentally determined rate
law, then the mechanism must be
correct.
A) True
B) False
50%
50%
1
2
Question 9
If a reaction is exothermic, then the
activation energy for the forward
reaction is __________ the activation
energy for the reverse reaction.
25%
25%
25%
2
3
25%
A) greater than
B) less than
C) equal to
D) none of the above--there is
no relationship between the
values
1
4
Question 10
Reactions rarely occur by mechanisms that
include trimolecular elementary steps
because
25%
25%
25%
2
3
25%
A) the simultaneous collision of three
molecules has a low probability.
B) simpler reaction mechanisms can
always support the same rate law.
C) the math involved is too
complicated.
D) all of the above.
1
4
Question 11
Which of the following can be used to
determine the rate of a chemical reaction?
20%
20%
20%
2
3
20%
20%
A) Measuring a change in color
B) Measuring a change in mass
C) Measuring a change in
concentration of a certain species
D) All of the above
E) None of the above
1
4
5
Question 12
The average rate of a reaction is the rate of
reaction at any given time.
A) True
B) False
50%
50%
1
2
Question 13
The rate of a reaction
25%
A) is always dependent of
the concentration of the reactants.
B) may or may not depend
on reactant concentration.
C) is never constant
throughout a reaction.
D) can be calculated for first
order and second order reactions
only.
1
25%
25%
2
3
25%
4
Question 15
In the reaction N2 + 3H2 → 2NH3, the
rate of formation of ammonia at a given
moment is 0.060 mol/s. What is the rate
of reaction of hydrogen gas at the same
20%
20%
20%
20%
20%
moment?
A) -0.060 mol/s
B) 0.090 mol/s
C) -0.090 mol/s
D) 0.040 mol/s
E) -0.040 mol/s
1
2
3
4
5
Question 16
The reaction C2H6 → 2CH3· is first order
with k = 2.50x10-3 s-1. How much time
will be necessary for the concentration
of C2H6 to decrease to 20 % of the initial
20%
20%
20%
20%
20%
amount?
A) 644 s
B) 280. s
C) 0.0025 s
D) 0.0005 s
E) None of the above
1
2
3
4
5
Question 17
The reaction C2H6 → 2CH3· is first order
with k = 2.5x10-3 s-1. Which of the
following changes in concentration will
last longer than the others?
20%
20%
20%
2
3
20%
20%
A) 2.0 M → 1.0 M
B) 1.0 M → 0.50 M
C) 0.50 M → 0.25 M
D) 0.80 M → 0.40 M
E) None of the above
1
4
5
Question 18
Which type of plot will be linear for a second
20%
20%
20%
20%
order reaction?
20%
A) [A] vs time
B) ln[A] vs time
C) 1/[A] vs time
D) [A]2 vs time
E) None is linear
1
2
3
4
5
Question 20
A unimolecular reaction follows first
order kinetics, and a bimolecular
reaction follows second order kinetics.
A) True
B) False
50%
50%
1
2
Answer Key – Chapter 13
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
D
A
E
D
D
B
B
B
B
A
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
D
B
B
C
C
A
A
C
C
B