chemistry raymond chang 10 th edition chapter 13 copyright © the mcgraw-hill companies, inc....
TRANSCRIPT
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
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A) rate = k[A]2[B].
B) rate = k[A][B]2.
C) rate = k[B]2.
D) none of the above.
Question 2
If the activation energy of a reaction is decreased, the reaction rate will increase.
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A) True
B) False
Question 3
Which of the following is true?
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20% 20% 20%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.
Question 5
Which of the following will cause the reaction rate to increase?
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A) Increasing the temperature.
B) Adding a catalyst.
C) Reducing the concentration of reactants.
D) Both A and B.
E) Both B and C.
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
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A) rate=k[A]2[B]
B) rate=k[A]2
C) rate=k[B]2
D) rate=k[A][B]
Question 8
If a proposed mechanism is consistent with the experimentally determined rate law, then the mechanism must be correct.
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A) True
B) False
Question 9
If a reaction is exothermic, then the activation energy for the forward reaction is __________ the activation energy for the reverse reaction.
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A) greater than
B) less than
C) equal to
D) none of the above--there is no relationship between the values
Question 10
Reactions rarely occur by mechanisms that include trimolecular elementary steps because
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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.
Question 11
Which of the following can be used to determine the rate of a chemical reaction?
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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
Question 12
The average rate of a reaction is the rate of reaction at any given time.
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A) True
B) False
Question 13
The rate of a reaction
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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.
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 moment?
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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
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
amount?
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A) 644 s
B) 280. s
C) 0.0025 s
D) 0.0005 s
E) None of the above
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?
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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
Question 18
Which type of plot will be linear for a second order reaction?
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A) [A] vs time
B) ln[A] vs time
C) 1/[A] vs time
D) [A]2 vs time
E) None is linear
Question 20
A unimolecular reaction follows first order kinetics, and a bimolecular reaction follows second order kinetics.
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A) True
B) False