Question 1

Phosgene, COCl2, is formed from Cl2 and CO at high temperatures. The mechanism is thought to be:

What is the rate law predicted for this mechanism?

Accepted Answer

Let the rate constant for the third (rat...

Question 2

Which unit is appropriate for describing reaction rates?

Accepted Answer

A)   kJ mol-1
B)   ( ∘\circ∘ 
C)   min-1
C)   M min-1
D)   kJ g-1
E)   g L-1 F) A) and C)
G) A) and B)

Question 3

For a reaction that is zeroth-order with respect to reactant A, and nth-order overall

Accepted Answer

A)   Rate = k[0]m[B]n
B)   Rate = k[B]n
C)   Rate = k[A]m[0]n
D)   Rate = k[A]m[B]0
E)   Rate = k[A]0[B]0F) All of the above
G) B) and C)

Question 4

Which statement, comparing catalyzed and uncatalyzed versions of a reaction, is incorrect?

Accepted Answer

A)   The initial and final energy states are the same.
B)   The reaction mechanisms are different.
C)   The reaction progress diagrams are different.
D)   The balanced equation for the overall reaction is the same.
E)   The activation energy is lower in the uncatalyzed reaction.F) A) and E)
G) D) and E) E

Question 5

Which of the following factors will affect the rate of a reaction only if it is heterogeneous?

Accepted Answer

A)   the surface area of the reactants
B)   the concentrations of reactants
C)   the concentrations of the products
D)   the temperature of the reaction system
E)   the presence of catalystsF) B) and E)
G) B) and D)

Question 6

The activation energy in the Arrhenius equation can best be described as

Accepted Answer

A)   a numerical description of the amount of energy released by colliding reactant molecules when they form products.
B)   a factor which corrects for the conversion between J and kJ.
C)   a numerical description of how often molecules collide with the proper orientation to react at a specific concentration.
D)   the probability that a collision between molecules will have the correct relative orientation for reaction to occur.
E)   a numerical description of the amount of energy needed by colliding reactant molecules in order to form products.F) A) and E)
G) C) and D)

Question 7

Which of the following factors will affect the rate of a homogeneous reaction?

Accepted Answer

A)   the presence of a catalyst, and, if one is present, its concentration
B)   the properties (particularly, molecular structure and bonding)  of reactants and products
C)   the concentrations of the reactants and sometimes the products
D)   the temperature at which the reaction occurs
E)   all of theseF) A) and B)
G) All of the above

Question 8

The decomposition of N2O(g)  to nitrogen and oxygen has the rate law 2O(g)  to nitrogen and oxygen has the rate law   where k = 1.1 × 10-3 M-1 s-1 at 565 \circ C. If the initial concentration of a sample of N2O is 0.50 M, what is the concentration after one hour at 565 \circ C? A)  9.5 × 10-3 M B)  2.2 × 10-3 M C)  0.029 M D)  0.17 M E)  0.46 M " class="answers-bank-image d-inline" rel="preload" > where k = 1.1 × 10-3 M-1 s-1 at 565 ∘\circ∘ C. If the initial concentration of a sample of N2O is 0.50 M, what is the concentration after one hour at 565 ∘\circ∘ C?

Accepted Answer

A)   9.5 × 10-3 M
B)   2.2 × 10-3 M
C)   0.029 M
D)   0.17 M
E)   0.46 M F) All of the above
G) A) and E) D

Question 9

Which statement about a rate constant is correct?

Accepted Answer

A)   Its units are always M min-1.
B)   Its value generally decreases as temperature increases.
C)   Its value depends on the concentration of the reactant(s) .
D)   Its value at a particular temperature depends on the reaction involved.
E)   It is symbolized by "K".F) A) and B)
G) B) and D)

Question 10

Consider this proposed mechanism for the reaction of NO2 and CO:
  a.	Write the overall reaction represented by this mechanism.
b.	What are the intermediates in this reaction, if any?
c.	What are the catalysts in this reaction, if any?
d.	Write the rate law predicted by the mechanism above.
e.	Write the rate law you would predict if the reaction went in a single step.

Accepted Answer

a. NO₂ + CO ® NO + CO₂ b. NO₃ is an intermediate; it is generated in the first step and used up in the second step. c. One of the NO₂ molecules is a catalyst, since it is used up in the first step and regenerated in the second step. d. Since the first step is slow (i.e., rate-determining), the rate law is rate = k[NO₂]₂ e. Rate = k[NO₂][CO].

Question 11

Exhibit 12-1 The following question(s)  relate to the reaction between water and a complex ion of Co2+; the rate varies with concentration as follows. (The rate has no dependence on [H2O].) 
2+; the rate varies with concentration as follows. (The rate has no dependence on [H2O].)    Refer to Exhibit 12-1. The value and units of the rate constant are: A)  3.6 × 103 M min-1. B)  2.8 × 10-4 M min-1. C)  3.6 × 103 min-1. D)  2.8 × 10-4 min-1. E)  3.6 × 103 M-1 min-1." class="answers-bank-image d-inline" rel="preload" > Refer to Exhibit 12-1. The value and units of the rate constant are:

Accepted Answer

A)   3.6 × 103 M min-1.
B)   2.8 × 10-4 M min-1.
C)   3.6 × 103 min-1.
D)   2.8 × 10-4 min-1.
E)   3.6 × 103 M-1 min-1.F) B) and D)
G) A) and C)

Question 12

The rate law for a given reaction is rate = k[reactant]2, with k = 2.64 × 10-4 M-1 min-1. If the initial concentration is 0.0250 M, what is the initial rate, with the correct units?

Accepted Answer

A)   4.36 × 10-11 M min-1
B)   1.65 × 10-7 min-1
C)   6.60 × 10-6 M min-1
D)   1.65 × 10-7 M min-1
E)   6.60 × 10-6 min-1F) All of the above
G) D) and E)

Question 13

A certain reaction is studied at room temperature, and gives a straight line plot for 1/[reactant] versus time. Which one of the following statements is true?

Accepted Answer

A)   The same reaction at a higher temperature would yield a similar plot parallel to the original graph, with a larger value for the y-intercept.
B)   The same reaction at a higher temperature would yield a similar plot parallel to the original graph, with a smaller value for the y-intercept.
C)   The reaction is second-order.
D)   The same reaction at a higher temperature would yield a plot with a smaller slope than the original graph, but with the same y-intercept.
E)   A graph of ln[reactant] versus 1/time will be a straight line at both temperatures.F) A) and D)
G) A) and C)

Question 14

For a zero-, first- or second-order reaction t vs. t, ln[A]t vs. t, and 1/[A]t vs. t D)  any of these E)  none of these" class="answers-bank-image d-inline" rel="preload" > the order of reaction with respect to reactant A may be determined

Accepted Answer

A)   from the specific rate law, if it is already known
B)   from the integrated rate law, if it is already known
C)   from plots of [A]t vs. t, ln[A]t vs. t, and 1/[A]t vs. t
D)   any of these
E)   none of theseF) B) and C)
G) A) and E)

Question 15

The frequency factor in the Arrhenius equation can best be described as

Accepted Answer

A)   the probability that a collision between molecules will have the correct relative orientation for reaction to occur.
B)   a numerical description of the amount of energy released by colliding reactant molecules when they form products.
C)   a numerical description of how often molecules collide with the proper orientation to react at a specific concentration.
D)   a numerical description of the amount of energy needed by colliding reactant molecules in order to form products.
E)   a factor which corrects for the conversion between J and kJ.F) C) and E)
G) B) and D)

Question 16

If the rate law for an elementary reaction is second order, we can conclude that

Accepted Answer

A)   no catalysts are involved in the reaction.
B)   no intermediates are formed in the reaction.
C)   additional experiments at different temperatures are needed to determine the molecularity of the reaction.
D)   the elementary reaction involves a collision between two molecules.
E)   the elementary reaction is unimolecular.F) B) and C)
G) B) and E)

Question 17

The kinetics of a reaction are observed to be third-order. The least likely mechanism

Accepted Answer

A)   involves three molecules reacting together in a single step.
B)   involves two molecules reacting in one step, and the third in a subsequent step.
C)   involves a single intermediate.
D)   involves more than one intermediate.
E)   involves a fast step followed by a slow step.F) C) and E)
G) All of the above

Question 18

The units for the rate constant k must always include

Accepted Answer

A)   a volume unit
B)   a concentration unit
C)   a time unit
D)   all of these
E)   none of theseF) A) and E)
G) C) and E)

Question 19

A heterogeneous reaction mixture may contain

Accepted Answer

A)   only a solid phase and a liquid phase
B)   only a gas phase and a solid phase
C)   only a gas phase and a liquid phase
D)   a gas phase, a solid phase, and a liquid phase
E)   any of theseF) C) and E)
G) A) and E)

Question 20

If a reaction is first-order with respect to each of its two reactants, then the rate of the reaction is

Accepted Answer

A)   inversely proportional to the concentration of each reactant
B)   directly proportional to the concentration of one reactant and inversely proportional to the concentration of the other reactant
C)   directly proportional to the inverse of the concentration of each of the two reactants
D)   unaffected by concentration as long as the concentrations of the two reactants are always equal to one another
E)   directly proportional to the concentration of each reactantF) A) and B)
G) A) and C)

Exam 12: Chemical Kinetics: Rates of Reactions

Phosgene, COCl₂, is formed from Cl₂ and CO at high temperatures. The mechanism is thought to be: What is the rate law predicted for this mechanism?

Correct Answer
verified
Let the rate constant for the third (rat...
View Answer

Which unit is appropriate for describing reaction rates?

Correct Answer
verified

For a reaction that is zeroth-order with respect to reactant A, and nth-order overall

Correct Answer
verified

Which statement, comparing catalyzed and uncatalyzed versions of a reaction, is incorrect?

Correct Answer
verified
E

Which of the following factors will affect the rate of a reaction only if it is heterogeneous?

Correct Answer
verified

The activation energy in the Arrhenius equation can best be described as

Correct Answer
verified

Which of the following factors will affect the rate of a homogeneous reaction?

Correct Answer
verified

Correct Answer
verified
D

Which statement about a rate constant is correct?

Correct Answer
verified

Exhibit 12-1 The following question(s) relate to the reaction between water and a complex ion of Co²⁺; the rate varies with concentration as follows. (The rate has no dependence on [H₂O].) Refer to Exhibit 12-1. The value and units of the rate constant are:

Correct Answer
verified

The rate law for a given reaction is rate = k[reactant]², with k = 2.64 × 10^-4 M^-1 min^-1. If the initial concentration is 0.0250 M, what is the initial rate, with the correct units?

Correct Answer
verified

A certain reaction is studied at room temperature, and gives a straight line plot for 1/[reactant] versus time. Which one of the following statements is true?

Correct Answer
verified

For a zero-, first- or second-order reaction the order of reaction with respect to reactant A may be determined

Correct Answer
verified

The frequency factor in the Arrhenius equation can best be described as

Correct Answer
verified

If the rate law for an elementary reaction is second order, we can conclude that

Correct Answer
verified

The kinetics of a reaction are observed to be third-order. The least likely mechanism

Correct Answer
verified

The units for the rate constant k must always include

Correct Answer
verified

A heterogeneous reaction mixture may contain

Correct Answer
verified

If a reaction is first-order with respect to each of its two reactants, then the rate of the reaction is

Correct Answer
verified

Exam 12: Chemical Kinetics: Rates of Reactions

Phosgene, COCl2, is formed from Cl2 and CO at high temperatures. The mechanism is thought to be: What is the rate law predicted for this mechanism?

Correct AnswerverifiedLet the rate constant for the third (rat...View AnswerShow Answer

Which unit is appropriate for describing reaction rates?

Correct AnswerverifiedShow Answer

For a reaction that is zeroth-order with respect to reactant A, and nth-order overall

Correct AnswerverifiedShow Answer

Which statement, comparing catalyzed and uncatalyzed versions of a reaction, is incorrect?

Correct AnswerverifiedE

Which of the following factors will affect the rate of a reaction only if it is heterogeneous?

Correct AnswerverifiedShow Answer

The activation energy in the Arrhenius equation can best be described as

Correct AnswerverifiedShow Answer

Which of the following factors will affect the rate of a homogeneous reaction?

Correct AnswerverifiedShow Answer

The decomposition of N2O(g) to nitrogen and oxygen has the rate law where k = 1.1 × 10-3 M-1 s-1 at 565 ∘\circ∘ C. If the initial concentration of a sample of N2O is 0.50 M, what is the concentration after one hour at 565 ∘\circ∘ C?

Correct AnswerverifiedD

Which statement about a rate constant is correct?

Correct AnswerverifiedShow Answer

Exhibit 12-1 The following question(s) relate to the reaction between water and a complex ion of Co2+; the rate varies with concentration as follows. (The rate has no dependence on [H2O].) Refer to Exhibit 12-1. The value and units of the rate constant are:

Correct AnswerverifiedShow Answer

The rate law for a given reaction is rate = k[reactant]2, with k = 2.64 × 10-4 M-1 min-1. If the initial concentration is 0.0250 M, what is the initial rate, with the correct units?

Correct AnswerverifiedShow Answer

A certain reaction is studied at room temperature, and gives a straight line plot for 1/[reactant] versus time. Which one of the following statements is true?

Correct AnswerverifiedShow Answer

For a zero-, first- or second-order reaction the order of reaction with respect to reactant A may be determined

Correct AnswerverifiedShow Answer

The frequency factor in the Arrhenius equation can best be described as

Correct AnswerverifiedShow Answer

If the rate law for an elementary reaction is second order, we can conclude that

Correct AnswerverifiedShow Answer

The kinetics of a reaction are observed to be third-order. The least likely mechanism

Correct AnswerverifiedShow Answer

The units for the rate constant k must always include

Correct AnswerverifiedShow Answer

A heterogeneous reaction mixture may contain

Correct AnswerverifiedShow Answer

If a reaction is first-order with respect to each of its two reactants, then the rate of the reaction is

Correct AnswerverifiedShow Answer

Phosgene, COCl₂, is formed from Cl₂ and CO at high temperatures. The mechanism is thought to be: What is the rate law predicted for this mechanism?

Correct Answer
verified
Let the rate constant for the third (rat...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
E

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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D

Correct Answer
verified

Exhibit 12-1 The following question(s) relate to the reaction between water and a complex ion of Co²⁺; the rate varies with concentration as follows. (The rate has no dependence on [H₂O].) Refer to Exhibit 12-1. The value and units of the rate constant are:

Correct Answer
verified

The rate law for a given reaction is rate = k[reactant]², with k = 2.64 × 10^-4 M^-1 min^-1. If the initial concentration is 0.0250 M, what is the initial rate, with the correct units?

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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