Question 1

A certain reaction has a rate constant of 8.8 s-1 at 298 K and 140 s-1 at 323 K.What is the activation energy for this reaction?

Accepted Answer

A) 38 kJ.mol-1  
B) 89 kJ.mol-1  
C) 120 kJ.mol-1  
D) 23 kJ.mol-1  
E) 1.2 kJ.mol-1  
A) 38 kJ.mol-1  
B) 89 kJ.mol-1  
C) 120 kJ.mol-1  
D) 23 kJ.mol-1  
E) 1.2 kJ.mol-1

Question 2

If the rate of a reaction increases by a factor of 64 when the concentration of reactant increases by a factor of 4,the order of the reaction with respect to this reactant is

Accepted Answer

A) 16. 
B) 2. 
C) 4. 
D) 1. 
E) 3. 
A) 16. 
B) 2. 
C) 4. 
D) 1. 
E) 3.

Question 3

For the reaction A $\rightarrow$products,the following data were collected.   
The half-life for this reaction is

Accepted Answer

A) 0.521 s 
B) 0.752 s 
C) 0.922 s 
D) 1.08 s 
A) 0.521 s 
B) 0.752 s 
C) 0.922 s 
D) 1.08 s

Question 4

A possible mechanism for the reaction 
2NO(g)+ O2(g)$\rightarrow$ 2NO2(g)is: 2NO(g) →N2O2(g)
K1,k1',fast
N2O2(g)+ O2(g)$\rightarrow$2NO2(g)
K2,slow
Application of the steady-state approximation gives

Accepted Answer

A) [N2O2] = 0. 
B) k1[NO]2 -k2[N2O2][O2] = 0. 
C) [N2O2] = (k1/k2)[NO]2.  
D) k1[NO]2 -k1'[N2O2] - k2[N2O2][O2] = 0. 
E) [N2O2] = (k1/k1')[NO]2.  
A) [N2O2] = 0. 
B) k1[NO]2 -k2[N2O2][O2] = 0. 
C) [N2O2] = (k1/k2)[NO]2.  
D) k1[NO]2 -k1'[N2O2] - k2[N2O2][O2] = 0. 
E) [N2O2] = (k1/k1')[NO]2.

Question 5

Consider the reaction 2N2O5(g)$\rightarrow$   4NO2(g)+ O2(g)
Rate = k[N2O5]
Calculate the time for the concentration of N2O5 to fall to one-fourth its initial value if the half-life is 133 s.

Accepted Answer

A) 133 s 
B) 33.3 s 
C) 266 s 
D) 66.6 s 
E) 533 s 
A) 133 s 
B) 33.3 s 
C) 266 s 
D) 66.6 s 
E) 533 s

Question 6

The reaction profile for the mechanism
 NO2(g)+ F2(g)$\rightarrow$NO2F(g)+ F(g)slow
F(g)+ NO2(g)$\rightarrow$NO2F(g)fast
Shows

Accepted Answer

A) two maxima,the first maximum being the higher. 
B) two maxima,the second maximum being the higher. 
C) one maximum for the second step. 
D) two maxima,both the same height. 
A) two maxima,the first maximum being the higher. 
B) two maxima,the second maximum being the higher. 
C) one maximum for the second step. 
D) two maxima,both the same height.

Question 7

For a zero-order reaction,the rate constant has the same units as the rate of reaction.

Accepted Answer

A) True 
 B)False

Question 8

For the reaction cyclobutane(g)$\rightarrow$  2ethylene(g)at 800 K,a plot of ln[cyclobutane] vs t gives a straight line with a slope of -1.6 s-1.Calculate the time needed for the concentration of cyclobutane to fall to 1/16 of its initial value.

Accepted Answer

A) 2.3 s 
B) 1.7 s 
C) 1.3 s 
D) 0.63 s 
E) 1.6 s 
A) 2.3 s 
B) 1.7 s 
C) 1.3 s 
D) 0.63 s 
E) 1.6 s

Question 9

Technetium-99m,used to image the heart and brain,has a half-life of 6.00 h.What fraction of technetium-99m remains in the body after 1 day?

Accepted Answer

A) 0.0625 
B) 0.250 
C) 0.0313 
D) 0.125 
A) 0.0625 
B) 0.250 
C) 0.0313 
D) 0.125

Question 10

It is important to distinguish between the reaction rate and the rate constant.The units of reaction rate are M∙s-1.

Accepted Answer

A) True 
 B)False

Question 11

All of the following statements with respect to the effect of a catalyst on a reaction are true except:

Accepted Answer

A) A catalyst has no effect on the equilibrium composition of the reaction. 
B) A catalyst provides a lower activation energy for the reaction. 
C) When a reaction is catalyzed,both forward and reverse reactions are accelerated. 
D) A catalyst speeds up a reaction by providing an alternate pathway for the reaction. 
E) When a catalyst speeds up a reaction,the rate law stays the same. 
A) A catalyst has no effect on the equilibrium composition of the reaction. 
B) A catalyst provides a lower activation energy for the reaction. 
C) When a reaction is catalyzed,both forward and reverse reactions are accelerated. 
D) A catalyst speeds up a reaction by providing an alternate pathway for the reaction. 
E) When a catalyst speeds up a reaction,the rate law stays the same.

Question 12

For the reaction cyclopropane(g)$\rightarrow$  propene(g)at 500S1U1P1$\circ$S1S1P0C,a plot of ln[cyclopropane] vs t gives a straight line with a slope of -0.00067 s-1.What is the order of this reaction and what is the rate constant?

Accepted Answer

first-orde

Question 13

The activation energy of a reaction is given by

Accepted Answer

A) +(slope of a plot of lnk vs 1/T)$\div$  R. 
B) -(slope of a plot of lnk vs 1/T)$\div$  R. 
C) -R $\div$  (slope of a plot of lnk vs 1/T). 
D) +(slope of a plot of lnk vs 1/T)* R. 
E) -(slope of a plot of lnk vs 1/T)* R. 
A) +(slope of a plot of lnk vs 1/T)$\div$  R. 
B) -(slope of a plot of lnk vs 1/T)$\div$  R. 
C) -R $\div$  (slope of a plot of lnk vs 1/T). 
D) +(slope of a plot of lnk vs 1/T)* R. 
E) -(slope of a plot of lnk vs 1/T)* R.

Question 14

What is the rate constant for a first-order reaction with a half-life of 9.0 ms?

Accepted Answer

A) 13 s-1  
B) 77 s-1  
C) 9.0 s-1  
D) 6.2 s-1  
E) 0.11 s-1  
A) 13 s-1  
B) 77 s-1  
C) 9.0 s-1  
D) 6.2 s-1  
E) 0.11 s-1

Question 15

The reaction 2NO(g)+ O2(g)$\rightarrow$ 2NO2(g)has $\Delta$HrS1U1P1$\circ$S1S1P0 = -114 kJ.mol-1.A possible mechanism for this reaction is
2NO(g)b N2O2(g)
rapid equilibrium,K
N2O2(g)+ O2(g)$\rightarrow$  2NO2(g)
slow,k
Draw the reaction profile diagram (plot of energy vs reaction coordinate)for this reaction and label any intermediates and activated complexes.

Accepted Answer

@#IMG-DLM& A and C are activat

Question 16

The HBr synthesis is thought to involve the following reactions:
 
The chain propagation reactions in this mechanism are reactions

Accepted Answer

A) 6. 
B) 1,2,3,and 6. 
C) 2 and 3. 
D) 1,2,and 3. 
E) 2,3,and 6. 
A) 6. 
B) 1,2,3,and 6. 
C) 2 and 3. 
D) 1,2,and 3. 
E) 2,3,and 6.

Question 17

For the reaction S2O82-(aq)+ 3I-(aq)$\rightarrow$ 2SO42-(aq)+ I3-(aq),rate = k[S2O82-][I-].When the reaction is followed under pseudo-first-order conditions with [S2O82-] = 200 m M and [I-] = 1.5 m M,the rate constant was 1.82 s-1.The second order rate constant,k,for the reaction is

Accepted Answer

A) 1.21 * 103 M-1.s-1. 
B) 6.07 * 103 M-1.s-1. 
C) 9.10 M-1.s-1. 
D) 1.37 * 10-2 M-1.s-1. 
E) 1.82 M-1.s-1. 
A) 1.21 * 103 M-1.s-1. 
B) 6.07 * 103 M-1.s-1. 
C) 9.10 M-1.s-1. 
D) 1.37 * 10-2 M-1.s-1. 
E) 1.82 M-1.s-1.

Question 18

The concentration-time dependence is shown below for two first-order reactions is:   
Which reaction has the larger rate constant?

Accepted Answer

the reacti

Question 19

Given: 5Br-(aq)+ BrO3-(aq)+ 6H+(aq)$\rightarrow$ 3Br2(aq)+ 3H2O(l)
Rate = k[Br-][ BrO3-][H+]2 
The overall order of the reaction and the order with respect to H+ are

Accepted Answer

A) 4 and 2. 
B) 5 and 6. 
C) 3 and 2. 
D) 5 and 2. 
E) 6 and 2. 
A) 4 and 2. 
B) 5 and 6. 
C) 3 and 2. 
D) 5 and 2. 
E) 6 and 2.

Question 20

The rates of first-order and second-order reactions do not change with elapsed time.

Accepted Answer

A) True 
 B)False

A certain reaction has a rate constant of 8.8 s^-1 at 298 K and 140 s^-1 at 323 K.What is the activation energy for this reaction?

If the rate of a reaction increases by a factor of 64 when the concentration of reactant increases by a factor of 4,the order of the reaction with respect to this reactant is

For the reaction A $\rightarrow$ products,the following data were collected. $For the reaction A \rightarrow products,the following data were collected. The half-life for this reaction is$ The half-life for this reaction is

A possible mechanism for the reaction 2NO(g)+ O₂(g) $\rightarrow$ 2NO₂(g)is: 2NO(g) →N₂O₂(g) K₁,k₁',fast N₂O₂(g)+ O₂(g) $\rightarrow$ 2NO₂(g) K₂,slow Application of the steady-state approximation gives

Consider the reaction 2N₂O₅(g) $\rightarrow$ 4NO₂(g)+ O₂(g) Rate = k[N₂O₅] Calculate the time for the concentration of N₂O₅ to fall to one-fourth its initial value if the half-life is 133 s.

The reaction profile for the mechanism NO₂(g)+ F₂(g) $\rightarrow$ NO₂F(g)+ F(g)slow F(g)+ NO₂(g) $\rightarrow$ NO₂F(g)fast Shows

For a zero-order reaction,the rate constant has the same units as the rate of reaction.

For the reaction cyclobutane(g) $\rightarrow$ 2ethylene(g)at 800 K,a plot of ln[cyclobutane] vs t gives a straight line with a slope of -1.6 s^-1.Calculate the time needed for the concentration of cyclobutane to fall to 1/16 of its initial value.

Technetium-99m,used to image the heart and brain,has a half-life of 6.00 h.What fraction of technetium-99m remains in the body after 1 day?

It is important to distinguish between the reaction rate and the rate constant.The units of reaction rate are M∙s^-1.

All of the following statements with respect to the effect of a catalyst on a reaction are true except:

For the reaction cyclopropane(g) $\rightarrow$ propene(g)at 500^$\circ$C,a plot of ln[cyclopropane] vs t gives a straight line with a slope of -0.00067 s^-1.What is the order of this reaction and what is the rate constant?

The activation energy of a reaction is given by

What is the rate constant for a first-order reaction with a half-life of 9.0 ms?

The HBr synthesis is thought to involve the following reactions: The chain propagation reactions in this mechanism are reactions

The concentration-time dependence is shown below for two first-order reactions is: Which reaction has the larger rate constant?

Given: 5Br^-(aq)+ BrO₃^-(aq)+ 6H⁺(aq) $\rightarrow$ 3Br₂(aq)+ 3H₂O(l) Rate = k[Br^-][ BrO₃^-][H⁺]² The overall order of the reaction and the order with respect to H⁺ are

The rates of first-order and second-order reactions do not change with elapsed time.

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Exam 15: Chemical Kinetics

A certain reaction has a rate constant of 8.8 s-1 at 298 K and 140 s-1 at 323 K.What is the activation energy for this reaction?

If the rate of a reaction increases by a factor of 64 when the concentration of reactant increases by a factor of 4,the order of the reaction with respect to this reactant is

For the reaction A →\rightarrow→ products,the following data were collected. The half-life for this reaction is

A possible mechanism for the reaction 2NO(g)+ O2(g) →\rightarrow→ 2NO2(g)is: 2NO(g) →N2O2(g) K1,k1',fast N2O2(g)+ O2(g) →\rightarrow→ 2NO2(g) K2,slow Application of the steady-state approximation gives

Consider the reaction 2N2O5(g) →\rightarrow→ 4NO2(g)+ O2(g) Rate = k[N2O5] Calculate the time for the concentration of N2O5 to fall to one-fourth its initial value if the half-life is 133 s.

The reaction profile for the mechanism NO2(g)+ F2(g) →\rightarrow→ NO2F(g)+ F(g)slow F(g)+ NO2(g) →\rightarrow→ NO2F(g)fast Shows

For a zero-order reaction,the rate constant has the same units as the rate of reaction.

For the reaction cyclobutane(g) →\rightarrow→ 2ethylene(g)at 800 K,a plot of ln[cyclobutane] vs t gives a straight line with a slope of -1.6 s-1.Calculate the time needed for the concentration of cyclobutane to fall to 1/16 of its initial value.

Technetium-99m,used to image the heart and brain,has a half-life of 6.00 h.What fraction of technetium-99m remains in the body after 1 day?

It is important to distinguish between the reaction rate and the rate constant.The units of reaction rate are M∙s-1.

All of the following statements with respect to the effect of a catalyst on a reaction are true except:

For the reaction cyclopropane(g) →\rightarrow→ propene(g)at 500 ∘\circ∘ C,a plot of ln[cyclopropane] vs t gives a straight line with a slope of -0.00067 s-1.What is the order of this reaction and what is the rate constant?

The activation energy of a reaction is given by

What is the rate constant for a first-order reaction with a half-life of 9.0 ms?

The HBr synthesis is thought to involve the following reactions: The chain propagation reactions in this mechanism are reactions

For the reaction S2O82-(aq)+ 3I-(aq) →\rightarrow→ 2SO42-(aq)+ I3-(aq),rate = k[S2O82-][I-].When the reaction is followed under pseudo-first-order conditions with [S2O82-] = 200 m M and [I-] = 1.5 m M,the rate constant was 1.82 s-1.The second order rate constant,k,for the reaction is

The concentration-time dependence is shown below for two first-order reactions is: Which reaction has the larger rate constant?

Given: 5Br-(aq)+ BrO3-(aq)+ 6H+(aq) →\rightarrow→ 3Br2(aq)+ 3H2O(l) Rate = k[Br-][ BrO3-][H+]2 The overall order of the reaction and the order with respect to H+ are

The rates of first-order and second-order reactions do not change with elapsed time.

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Aqueous Equilibria

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A certain reaction has a rate constant of 8.8 s^-1 at 298 K and 140 s^-1 at 323 K.What is the activation energy for this reaction?

For the reaction A $\rightarrow$ products,the following data were collected. $For the reaction A \rightarrow products,the following data were collected. The half-life for this reaction is$ The half-life for this reaction is

A possible mechanism for the reaction 2NO(g)+ O₂(g) $\rightarrow$ 2NO₂(g)is: 2NO(g) →N₂O₂(g) K₁,k₁',fast N₂O₂(g)+ O₂(g) $\rightarrow$ 2NO₂(g) K₂,slow Application of the steady-state approximation gives

Consider the reaction 2N₂O₅(g) $\rightarrow$ 4NO₂(g)+ O₂(g) Rate = k[N₂O₅] Calculate the time for the concentration of N₂O₅ to fall to one-fourth its initial value if the half-life is 133 s.

The reaction profile for the mechanism NO₂(g)+ F₂(g) $\rightarrow$ NO₂F(g)+ F(g)slow F(g)+ NO₂(g) $\rightarrow$ NO₂F(g)fast Shows

For the reaction cyclobutane(g) $\rightarrow$ 2ethylene(g)at 800 K,a plot of ln[cyclobutane] vs t gives a straight line with a slope of -1.6 s^-1.Calculate the time needed for the concentration of cyclobutane to fall to 1/16 of its initial value.

It is important to distinguish between the reaction rate and the rate constant.The units of reaction rate are M∙s^-1.

For the reaction cyclopropane(g) $\rightarrow$ propene(g)at 500^$\circ$C,a plot of ln[cyclopropane] vs t gives a straight line with a slope of -0.00067 s^-1.What is the order of this reaction and what is the rate constant?

Given: 5Br^-(aq)+ BrO₃^-(aq)+ 6H⁺(aq) $\rightarrow$ 3Br₂(aq)+ 3H₂O(l) Rate = k[Br^-][ BrO₃^-][H⁺]² The overall order of the reaction and the order with respect to H⁺ are