Question 1

The reaction A  →	o→  B is first-order overall and first-order with respect to the reactant A.The result of doubling the initial concentration of A will be to

Accepted Answer

A)  shorten the half-life of the reaction.
B)  increase the rate constant of the reaction.
C)  decrease the rate constant of the reaction.
D)  shorten the time taken to reach equilibrium.
E)  double the initial rate. F) All of the above
G) A) and C)

Question 2

The decomposition of dinitrogen pentaoxide to nitrogen dioxide and oxygen follows first-order kinetics and has an activation energy of 102 kJ/mol.By what factor will the fraction of collisions with energy greater than or equal to the activation energy increase if the reaction temperature goes from 30°C to 60°C?

Accepted Answer

A)  1.00
B)  1.10
C)  2.00
D)  4.00
E)  38.4F) B) and E)
G) None of the above

Question 3

A $\to$ B
At very low pressures many such reactions occur by the following mechanism:
  
(A* represents a molecule with sufficient energy to overcome the activation energy barrier. )
a.Which of the three reactions above is/are elementary?
b.Where appropriate,identify the molecularity of the reactions.
c.Show that the proposed mechanism is consistent with reaction 1,the observed reaction.
d.Given the mechanism above,suggest a likely rate law for reaction (1).

Accepted Answer

a.Reactions 2 and 3 are elementary.
b.Re...

Question 4

The kinetics of the decomposition of dinitrogen pentaoxide is studied at 50°C and at 75°C.Which of the following statements concerning the studies is correct?

Accepted Answer

A)  The rate at 75°C will be greater than the rate at 50°C because the activation energy will be lower at 75°C than at 50°C.
B)  The rate at 75°C will be greater than the rate at 50°C because the activation energy will be higher at 75°C than at 50°C.
C)  The rate at 75°C will be less than the rate at 50°C because the molecules at higher speeds do not interact as well as those at lower speeds.
D)  The rate at 75°C will be greater than at 50°C because the concentration of a gas increases with increasing temperature.
E)  The rate at 75°C will be greater than the rate at 50°C because the number of molecules with enough energy to react increases with increasing temperature.F) B) and C)
G) B) and E)

Question 5

A chemical reaction of the general type
A $\to$ 2B
is first-order,with a rate constant of 1.52 $\times$ 10-4 s-1.
a.Calculate the half-life of A.
b.Assuming the initial concentration of A is 0.067 mol L-1,calculate the time needed for the concentration to fall to 0.010 mol L-1.

Accepted Answer

a.t

= 4.56

10^...

Question 6

Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution.
H+ + H2O2 + + H2O2   H2O+-OH (rapid equilibrium)  H2O+-OH + Br-  	o  HOBr + H2O (slow)  HOBr + H+ + Br-  	o  Br2 + H2O (fast)  Which of the following rate laws is consistent with the mechanism? A) Rate = k[H2O2][H+]2[Br-] B) Rate = k [H2O+-OH][Br-] C) Rate = k[H2O2][H+][Br-] D) Rate = k[HOBr][H+][Br-][H2O2] E) Rate = k[Br-] " class="answers-bank-image d-inline" rel="preload" >
H2O+-OH (rapid equilibrium) 
H2O+-OH + Br-  →	o→  HOBr + H2O (slow) 
HOBr + H+ + Br-  →	o→  Br2 + H2O (fast) 
Which of the following rate laws is consistent with the mechanism?

Accepted Answer

A)  Rate = k[H2O2][H+]2[Br-]
B)  Rate = k [H2O+-OH][Br-]
C)  Rate = k[H2O2][H+][Br-]
D)  Rate = k[HOBr][H+][Br-][H2O2]
E)  Rate = k[Br-] F) B) and E)
G) A) and B)

Question 7

A reactant R is being consumed in a first-order reaction.What fraction of the initial R is consumed in 4.0 half-lives?

Accepted Answer

A)  0.94
B)  0.87
C)  0.75
D)  0.13
E)  0.063F) D) and E)
G) A) and D)

Question 8

The half-life of a second-order reaction does not depend on the initial concentration of reactant.

Accepted Answer

A) True 
 B)False

Question 9

Which one of the following sets of units is appropriate for a second-order rate constant?

Accepted Answer

A)  s-1
B)  mol L-1 s-1
C)  L mol-1 s-1
D)  mol2 L-2 s-1
E)  L2 mol-2 s-1F) B) and E)
G) D) and E)

Question 10

The units of the rate of reaction depend on the order of the reaction.

Accepted Answer

A) True 
 B)False

Question 11

When the reaction A  →	o→  B + C is studied,a plot 1/[A]t vs.time gives a straight line with a positive slope.What is the order of the reaction?

Accepted Answer

A)  zero
B)  first
C)  second
D)  third
E)  More information is needed to determine the order. F) A) and D)
G) A) and C)

Question 12

Which one of the following sets of units is appropriate for a third-order rate constant?

Accepted Answer

A)  s-1
B)  mol L-1 s-1
C)  L mol-1 s-1
D)  L2 mol-2 s-1
E)  L3 mol-3 s-1F) C) and D)
G) D) and E)

Question 13

The rate constant for the reaction 3A  →	o→  4B is 6.00  ×	imes×  10-3 L mol-1min-1.How long will it take the concentration of A to drop from 0.75 M to 0.25 M?

Accepted Answer

A)  2.2  ×	imes×  10-3 min
B)  5.5  ×	imes×  10-3 min
C)  180 min
D)  440 min
E)  5.0  ×	imes×  102 min F) B) and D)
G) C) and D)

Question 14

Is a bimolecular reaction necessarily second-order? Is a second-order reaction necessarily bimolecular? Answer,with explanations and clarifications.

Accepted Answer

For elementary reactions,the order follo...

Question 15

Briefly list the features/properties common to all catalysts and how they work.Draw a labeled reaction energy diagram as part of your answer.

Accepted Answer

Catalysts speed up a reaction ...

Question 16

Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution.
H+ + H2O2 + + H2O2   H2O+-OH (rapid equilibrium)  H2O+-OH + Br-  	o  HOBr + H2O (slow)  HOBr + H+ + Br-  	o  Br2 + H2O (fast)  What is the overall reaction equation for this process? A) 2H2O+-OH + 2Br-  	o  H2O2 + Br2 + 2H2O B) 2H+ + 2Br- + H2O2  	o  Br2 + 2H2O C) 2H+ + H2O2 + Br- + HOBr  	o  H2O+-OH + Br2 + H2O D) H2O+-OH + Br- + H+  	o  Br2 + H2O E) None of these choices is correct. " class="answers-bank-image d-inline" rel="preload" >
H2O+-OH (rapid equilibrium) 
H2O+-OH + Br-  →	o→  HOBr + H2O (slow) 
HOBr + H+ + Br-  →	o→  Br2 + H2O (fast) 
What is the overall reaction equation for this process?

Accepted Answer

A)  2H2O+-OH + 2Br-  →	o→  H2O2 + Br2 + 2H2O
B)  2H+ + 2Br- + H2O2  →	o→  Br2 + 2H2O
C)  2H+ + H2O2 + Br- + HOBr  →	o→  H2O+-OH + Br2 + H2O
D)  H2O+-OH + Br- + H+  →	o→  Br2 + H2O
E)  None of these choices is correct. F) B) and C)
G) A) and E)

Question 17

The rate law for the rearrangement of CH3NC to CH3CN at 800 K is rate = (1300 s-1) [CH3NC].What is the half-life for this reaction?

Accepted Answer

A)  7.69  ×	imes×  10-4 s
B)  5.3  ×	imes×  10-4 s
C)  1.9  ×	imes×  10-3 s
D)  520 s
E)  1920 s F) C) and D)
G) A) and E)

Question 18

The compound RX3 decomposes according to the equation
3RX3   \(\to\0 R + R2X3 + 3X2
 In an experiment the following data were collected for the decomposition at 100°C.What is the average rate of reaction over the entire experiment?
3 decomposes according to the equation 3RX3   \(\to\0 R + R2X3 + 3X2  In an experiment the following data were collected for the decomposition at 100°C.What is the average rate of reaction over the entire experiment?   A) 0.011 mol L-1s-1 B) 0.019 mol L-1s-1 C) 0.044 mol L-1s-1 D) 0.049 mol L-1s-1 E) 0.069 mol L-1s-1 " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  0.011 mol L-1s-1
B)  0.019 mol L-1s-1
C)  0.044 mol L-1s-1
D)  0.049 mol L-1s-1
E)  0.069 mol L-1s-1 F) C) and D)
G) B) and E)

Question 19

You are studying the rate of the reaction 2A $\to$ B and have obtained measurements of the concentration of A at times t = 100,200,300,...... ,1000 seconds from the start of the reaction.Carefully describe how you would plot a graph and use it to
a.prove that the reaction is second-order with respect to A.
b.determine the second-order rate constant k.

Accepted Answer

a.Plot 1/[A] versus time.If a ...

Question 20

Consider the general reaction
5Br-(aq) + BrO3-(aq) + 6H+(aq)   →	o→ 3Br2(aq) + 3H2O(aq) 
For this reaction,the rate when expressed as  Δ\DeltaΔ [Br2]/ Δ\DeltaΔ t is the same as

Accepted Answer

A)  - Δ\DeltaΔ [H2O]/ Δ\DeltaΔ t
B)  3 Δ\DeltaΔ [BrO3-]/ Δ\DeltaΔ t
C)  -5 Δ\DeltaΔ [Br-]/ Δ\DeltaΔ t
D)  -0.6 Δ\DeltaΔ [Br-]/ Δ\DeltaΔ t
E)  None of these choices is correct. F) D) and E)
G) C) and D)

Exam 16: Kinetics: Rates and Mechanisms of Chemical Reactions

Is a bimolecular reaction necessarily second-order? Is a second-order reaction necessarily bimolecular? Answer,with explanations and clarifications.

Correct Answer
verified
For elementary reactions,the order follo...
View Answer

Correct Answer
verified

The rate constant for the reaction 3A $\to$ 4B is 6.00 $\times$ 10^-3 L mol^-1min^-1.How long will it take the concentration of A to drop from 0.75 M to 0.25 M?

Correct Answer
verified

Which one of the following sets of units is appropriate for a third-order rate constant?

Correct Answer
verified

Correct Answer
verified

Briefly list the features/properties common to all catalysts and how they work.Draw a labeled reaction energy diagram as part of your answer.

Correct Answer
verified
Catalysts speed up a reaction ...
View Answer

Correct Answer
verified
a.Plot 1/[A] versus time.If a ...
View Answer

Correct Answer
verified

The rate law for the rearrangement of CH₃NC to CH₃CN at 800 K is rate = (1300 s^-1) [CH₃NC].What is the half-life for this reaction?

Correct Answer
verified

The half-life of a second-order reaction does not depend on the initial concentration of reactant.

Correct Answer
verified

Correct Answer
verified
a.Reactions 2 and 3 are elementary.
b.Re...
View Answer

The units of the rate of reaction depend on the order of the reaction.

Correct Answer
verified

Correct Answer
verified

Consider the general reaction 5Br^-(aq) + BrO₃^-(aq) + 6H⁺(aq) $\to$ 3Br₂(aq) + 3H₂O(aq) For this reaction,the rate when expressed as $\Delta$ [Br₂]/ $\Delta$ t is the same as

Correct Answer
verified

The kinetics of the decomposition of dinitrogen pentaoxide is studied at 50°C and at 75°C.Which of the following statements concerning the studies is correct?

Correct Answer
verified

Which one of the following sets of units is appropriate for a second-order rate constant?

Correct Answer
verified

When the reaction A $\to$ B + C is studied,a plot 1/[A]_t vs.time gives a straight line with a positive slope.What is the order of the reaction?

Correct Answer
verified

A chemical reaction of the general type A $\to$ 2B is first-order,with a rate constant of 1.52 $\times$ 10^-4 s^-1. a.Calculate the half-life of A. b.Assuming the initial concentration of A is 0.067 mol L^-1,calculate the time needed for the concentration to fall to 0.010 mol L^-1.

Correct Answer
verified
a.t = 4.56 10^...
View Answer

The reaction A $\to$ B is first-order overall and first-order with respect to the reactant A.The result of doubling the initial concentration of A will be to

Correct Answer
verified

A reactant R is being consumed in a first-order reaction.What fraction of the initial R is consumed in 4.0 half-lives?

Correct Answer
verified

Exam 16: Kinetics: Rates and Mechanisms of Chemical Reactions

Is a bimolecular reaction necessarily second-order? Is a second-order reaction necessarily bimolecular? Answer,with explanations and clarifications.

Correct AnswerverifiedFor elementary reactions,the order follo...View AnswerShow Answer

Correct AnswerverifiedShow Answer

The rate constant for the reaction 3A →\to→ 4B is 6.00 ×\times× 10-3 L mol-1min-1.How long will it take the concentration of A to drop from 0.75 M to 0.25 M?

Correct AnswerverifiedShow Answer

Which one of the following sets of units is appropriate for a third-order rate constant?

Correct AnswerverifiedShow Answer

The compound RX3 decomposes according to the equation 3RX3 \(\to\0 R + R2X3 + 3X2 In an experiment the following data were collected for the decomposition at 100°C.What is the average rate of reaction over the entire experiment?

Correct AnswerverifiedShow Answer

Briefly list the features/properties common to all catalysts and how they work.Draw a labeled reaction energy diagram as part of your answer.

Correct AnswerverifiedCatalysts speed up a reaction ...View AnswerShow Answer

Correct Answerverifieda.Plot 1/[A] versus time.If a ...View AnswerShow Answer

Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution. H+ + H2O2 H2O+-OH (rapid equilibrium) H2O+-OH + Br- →\to→ HOBr + H2O (slow) HOBr + H+ + Br- →\to→ Br2 + H2O (fast) What is the overall reaction equation for this process?

Correct AnswerverifiedShow Answer

The rate law for the rearrangement of CH3NC to CH3CN at 800 K is rate = (1300 s-1) [CH3NC].What is the half-life for this reaction?

Correct AnswerverifiedShow Answer

The half-life of a second-order reaction does not depend on the initial concentration of reactant.

Correct AnswerverifiedShow Answer

Correct Answerverifieda.Reactions 2 and 3 are elementary.b.Re...View AnswerShow Answer

The units of the rate of reaction depend on the order of the reaction.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Consider the general reaction 5Br-(aq) + BrO3-(aq) + 6H+(aq) →\to→ 3Br2(aq) + 3H2O(aq) For this reaction,the rate when expressed as Δ\DeltaΔ [Br2]/ Δ\DeltaΔ t is the same as

Correct AnswerverifiedShow Answer

The kinetics of the decomposition of dinitrogen pentaoxide is studied at 50°C and at 75°C.Which of the following statements concerning the studies is correct?

Correct AnswerverifiedShow Answer

Which one of the following sets of units is appropriate for a second-order rate constant?

Correct AnswerverifiedShow Answer

When the reaction A →\to→ B + C is studied,a plot 1/[A]t vs.time gives a straight line with a positive slope.What is the order of the reaction?

Correct AnswerverifiedShow Answer

A chemical reaction of the general type A →\to→ 2B is first-order,with a rate constant of 1.52 ×\times× 10-4 s-1. a.Calculate the half-life of A. b.Assuming the initial concentration of A is 0.067 mol L-1,calculate the time needed for the concentration to fall to 0.010 mol L-1.

Correct Answerverifieda.t = 4.56 10...View AnswerShow Answer

The reaction A →\to→ B is first-order overall and first-order with respect to the reactant A.The result of doubling the initial concentration of A will be to

Correct AnswerverifiedShow Answer

A reactant R is being consumed in a first-order reaction.What fraction of the initial R is consumed in 4.0 half-lives?

Correct AnswerverifiedShow Answer

Correct Answer
verified
For elementary reactions,the order follo...
View Answer

Correct Answer
verified

The rate constant for the reaction 3A $\to$ 4B is 6.00 $\times$ 10^-3 L mol^-1min^-1.How long will it take the concentration of A to drop from 0.75 M to 0.25 M?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Catalysts speed up a reaction ...
View Answer

Correct Answer
verified
a.Plot 1/[A] versus time.If a ...
View Answer

Correct Answer
verified

The rate law for the rearrangement of CH₃NC to CH₃CN at 800 K is rate = (1300 s^-1) [CH₃NC].What is the half-life for this reaction?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
a.Reactions 2 and 3 are elementary.
b.Re...
View Answer

Correct Answer
verified

Correct Answer
verified

Consider the general reaction 5Br^-(aq) + BrO₃^-(aq) + 6H⁺(aq) $\to$ 3Br₂(aq) + 3H₂O(aq) For this reaction,the rate when expressed as $\Delta$ [Br₂]/ $\Delta$ t is the same as

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

When the reaction A $\to$ B + C is studied,a plot 1/[A]_t vs.time gives a straight line with a positive slope.What is the order of the reaction?

Correct Answer
verified

A chemical reaction of the general type A $\to$ 2B is first-order,with a rate constant of 1.52 $\times$ 10^-4 s^-1. a.Calculate the half-life of A. b.Assuming the initial concentration of A is 0.067 mol L^-1,calculate the time needed for the concentration to fall to 0.010 mol L^-1.

Correct Answer
verified
a.t = 4.56 10^...
View Answer

The reaction A $\to$ B is first-order overall and first-order with respect to the reactant A.The result of doubling the initial concentration of A will be to

Correct Answer
verified

Correct Answer
verified