Question 1

Rates of reaction can be positive or negative.

Accepted Answer

A) True 
 B)False

Question 2

The rate constant for a particular second- order reaction is 0.47 M- 1s- 1. If the initial concentration of reactant is 0.25 mol/L, it takes s for the concentration to decrease to 0.13 mol/L.

Accepted Answer

A)  1.7 
B)  1.4 
C)  7.9 
D)  0.13 
E)  3.7 
A)  1.7 
B)  1.4 
C)  7.9 
D)  0.13 
E)  3.7

Question 3

The average rate of disappearance of I in the initial 400 s is _ M/s.

Accepted Answer

A)  3.8 × 10- 5  
B)  3.2 × 10- 4  
C)  1.4 × 10- 4  
D)  2.7 × 104  
E)  6.00 
A)  3.8 × 10- 5  
B)  3.2 × 10- 4  
C)  1.4 × 10- 4  
D)  2.7 × 104  
E)  6.00

Question 4

The initial concentration of reactant in a first- order reaction is 0.27 M. The rate constant for the reaction is 0.75 s- 1. What is the concentration (mol/L) of reactant after 1.5 s?

Accepted Answer

A)  1.7 
B)  2.0 × 10- 2  
C)  3.8 
D)  0.135 
E)  8.8 × 10- 2 
A)  1.7 
B)  2.0 × 10- 2  
C)  3.8 
D)  0.135 
E)  8.8 × 10- 2

Question 5

Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction:
2NO2 → 2NO + O2
In a particular experiment at 300°C, [NO2] drops from 0.0100 to 0.00650 M in 100 s. The rate of appearance of O2 for this period is _ M/s.

Accepted Answer

A)  7.0 × 10- 5  
B)  3.5 × 10- 3  
C)  7.0 × 10- 3  
D)  3.5 × 10- 5  
E)  1.8 × 10- 5 
A)  7.0 × 10- 5  
B)  3.5 × 10- 3  
C)  7.0 × 10- 3  
D)  3.5 × 10- 5  
E)  1.8 × 10- 5

Question 6

One difference between first- and second- order reactions is that .

Accepted Answer

A)  the rate of a first- order reaction does not depend on reactant concentrations; the rate of a second- order reaction does depend on reactant concentrations 
B)  a first- order reaction can be catalyzed; a second- order reaction cannot be catalyzed 
C)  the rate of a first- order reaction depends on reactant concentrations; the rate of a second- order reaction does not depend on reactant concentrations 
D)  the half- life of a first- order reaction depends on [A]0; the half- life of a second- order reaction does not depend on [A]0 
E)  the half- life of a first- order reaction does not depend on [A]0; the half- life of a second- order reaction does depend on [A]0 
A)  the rate of a first- order reaction does not depend on reactant concentrations; the rate of a second- order reaction does depend on reactant concentrations 
B)  a first- order reaction can be catalyzed; a second- order reaction cannot be catalyzed 
C)  the rate of a first- order reaction depends on reactant concentrations; the rate of a second- order reaction does not depend on reactant concentrations 
D)  the half- life of a first- order reaction depends on [A]0; the half- life of a second- order reaction does not depend on [A]0 
E)  the half- life of a first- order reaction does not depend on [A]0; the half- life of a second- order reaction does depend on [A]0

Question 7

The half- life of a first- order reaction .

Accepted Answer

A)  is constant 
B)  does not depend on the initial reactant concentration 
C)  can be calculated from the reaction rate constant 
D)  is the time necessary for the reactant concentration to drop to half its original value 
E)  All of the above are correct. 
A)  is constant 
B)  does not depend on the initial reactant concentration 
C)  can be calculated from the reaction rate constant 
D)  is the time necessary for the reactant concentration to drop to half its original value 
E)  All of the above are correct.

Question 8

The reaction A - B is first order in [A]. Consider the following data.  
-The rate constant for this reaction is s- 1.

Accepted Answer

A)  3.1 × 10- 3  
B)  0.013 
C)  0.14 
D)  3.0 
E)  0.030 
A)  3.1 × 10- 3  
B)  0.013 
C)  0.14 
D)  3.0 
E)  0.030

Question 9

A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) -B(g). The following data are obtained for [A] as the reaction proceeds:  
-The average rate of disappearance of A between 20 s and 40 s is mol/s.

Accepted Answer

A)  1.4 × 10- 3  
B)  590 
C)  8.5 × 10- 4  
D)  7.1 × 10- 3  
E)  1.7 × 10- 3 
A)  1.4 × 10- 3  
B)  590 
C)  8.5 × 10- 4  
D)  7.1 × 10- 3  
E)  1.7 × 10- 3

Question 10

At elevated temperatures, methylisonitrile (CH3NC) isomerizes to acetonitrile (CH3CN):
CH3NC (g) → CH3CN (g)
The dependence of the rate constant on temperature is studied and the graph below is prepared from the results.
 
The energy of activation of this reaction is kJ/mol.

Accepted Answer

A)  1.6 × 105  
B)  1.9 × 104  
C)  4.4 × 10- 4  
D)  160 
E)  4.4 × 10- 7 
A)  1.6 × 105  
B)  1.9 × 104  
C)  4.4 × 10- 4  
D)  160 
E)  4.4 × 10- 7

Question 11

At elevated temperatures, methylisonitrile (CH3NC) isomerizes to acetonitrile (CH3CN):
CH3NC (g) → CH33CN (g)
The reaction is first order in methylisonitrile. The attached graph shows data for the reaction obtained at 198.9°C.
 
The rate constant for the reaction is s- 1.

Accepted Answer

A)  +5.2 × 10- 5 
B)  +6.2 
C)  +1.9 × 104 
D)  - 5.2 × 10- 5 
E)  - 1.9 × 104 
A)  +5.2 × 10- 5 
B)  +6.2 
C)  +1.9 × 104 
D)  - 5.2 × 10- 5 
E)  - 1.9 × 104

Question 12

The data in the table below were obtained for the reaction:
2 ClOS1U1B12 S1U1B0(aq) + 2 OHS1U1P1- S1S1P0(aq) → ClOS1U1B13S1U1B0S1U1P1- S1S1P0(aq) + ClOS1U1B12S1U1B0S1U1P1- S1S1P0(aq) + HS1U1B12S1U1B0O (1)  
-What is the overall order of the reaction?

Accepted Answer

A)  4 
B)  2 
C)  1 
D)  3 
E)  0 
A)  4 
B)  2 
C)  1 
D)  3 
E)  0

Question 13

The rate of a second order reaction can depend on the concentrations of more than one reactant .

Accepted Answer

A) True 
 B)False

Question 14

The average rate of disappearance of I between 1200 s and 1600 s is _ M/s.

Accepted Answer

A)  1.2 × 10- 5  
B)  5.0 × 104  
C)  1.8 × 10- 5  
D)  2.0 × 10- 5  
E)  1.6 × 10- 4 
A)  1.2 × 10- 5  
B)  5.0 × 104  
C)  1.8 × 10- 5  
D)  2.0 × 10- 5  
E)  1.6 × 10- 4

Question 15

The half life for a first order rate law depends on the starting concentration.

Accepted Answer

A) True 
 B)False

Question 16

A second- order reaction has a half- life of 18 s when the initial concentration of reactant is 0.71 M. The rate constant for this reaction is M- 1s- 1.

Accepted Answer

A)  3.8 × 10- 2  
B)  7.8 × 10- 2  
C)  18 
D)  1.3 
E)  2.0 × 10- 2 
A)  3.8 × 10- 2  
B)  7.8 × 10- 2  
C)  18 
D)  1.3 
E)  2.0 × 10- 2

Question 17

The overall reactions and rate laws for several reactions are given below. Of these, only _ could represent an elementary step.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 18

The instantaneous rate of a reaction can be determined from the graph of molarity versus time at any point on the graph.

Accepted Answer

A) True 
 B)False

Question 19

A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) -B(g). The following data are obtained for [A] as the reaction proceeds:  
-How many moles of B are present at 30 s?

Accepted Answer

A)  0.051 
B)  0.073 
C)  2.4 × 10- 3  
D)  1.7 × 10- 3  
E)  0.15 
A)  0.051 
B)  0.073 
C)  2.4 × 10- 3  
D)  1.7 × 10- 3  
E)  0.15

Question 20

The reaction A (aq) - B (aq) is first order in [A]. A solution is prepared with [A] = 1.22 M. The following data are obtained as the reaction proceeds:
 
The rate constant for this reaction is s- 1.

Accepted Answer

A)  0.17 
B)  - 0.12 
C)  0.23 
D)  1.0 
E)  0.12 
A)  0.17 
B)  - 0.12 
C)  0.23 
D)  1.0 
E)  0.12

Exam 14: Chemical Kinetics

Rates of reaction can be positive or negative.

The rate constant for a particular second- order reaction is 0.47 M- 1s- 1. If the initial concentration of reactant is 0.25 mol/L, it takes s for the concentration to decrease to 0.13 mol/L.

The average rate of disappearance of I in the initial 400 s is _ M/s.

The initial concentration of reactant in a first- order reaction is 0.27 M. The rate constant for the reaction is 0.75 s- 1. What is the concentration (mol/L) of reactant after 1.5 s?

Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction: 2NO2 → 2NO + O2 In a particular experiment at 300°C, [NO2] drops from 0.0100 to 0.00650 M in 100 s. The rate of appearance of O2 for this period is _ M/s.

One difference between first- and second- order reactions is that .

The half- life of a first- order reaction .

The reaction A - B is first order in [A]. Consider the following data. -The rate constant for this reaction is s- 1.

A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) -B(g). The following data are obtained for [A] as the reaction proceeds: -The average rate of disappearance of A between 20 s and 40 s is mol/s.

At elevated temperatures, methylisonitrile (CH3NC) isomerizes to acetonitrile (CH3CN): CH3NC (g) → CH3CN (g) The dependence of the rate constant on temperature is studied and the graph below is prepared from the results. The energy of activation of this reaction is kJ/mol.

At elevated temperatures, methylisonitrile (CH3NC) isomerizes to acetonitrile (CH3CN): CH3NC (g) → CH33CN (g) The reaction is first order in methylisonitrile. The attached graph shows data for the reaction obtained at 198.9°C. The rate constant for the reaction is s- 1.

The data in the table below were obtained for the reaction: 2 ClO2 (aq) + 2 OH- (aq) → ClO3- (aq) + ClO2- (aq) + H2O (1) -What is the overall order of the reaction?

The rate of a second order reaction can depend on the concentrations of more than one reactant .

The average rate of disappearance of I between 1200 s and 1600 s is _ M/s.

The half life for a first order rate law depends on the starting concentration.

A second- order reaction has a half- life of 18 s when the initial concentration of reactant is 0.71 M. The rate constant for this reaction is M- 1s- 1.

The overall reactions and rate laws for several reactions are given below. Of these, only _ could represent an elementary step.

The instantaneous rate of a reaction can be determined from the graph of molarity versus time at any point on the graph.

A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) -B(g). The following data are obtained for [A] as the reaction proceeds: -How many moles of B are present at 30 s?

The reaction A (aq) - B (aq) is first order in [A]. A solution is prepared with [A] = 1.22 M. The following data are obtained as the reaction proceeds: The rate constant for this reaction is s- 1.

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The rate constant for a particular second- order reaction is 0.47 M^-¹s^-¹. If the initial concentration of reactant is 0.25 mol/L, it takes s for the concentration to decrease to 0.13 mol/L.

The initial concentration of reactant in a first- order reaction is 0.27 M. The rate constant for the reaction is 0.75 s^-¹. What is the concentration (mol/L) of reactant after 1.5 s?

Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction: 2NO₂→ 2NO + O₂ In a particular experiment at 300°C, [NO₂] drops from 0.0100 to 0.00650 M in 100 s. The rate of appearance of O₂for this period is _ M/s.

The reaction A - B is first order in [A]. Consider the following data. -The rate constant for this reaction is s^-¹.

At elevated temperatures, methylisonitrile (CH₃NC) isomerizes to acetonitrile (CH₃CN): CH₃NC (g) → CH₃CN (g) The dependence of the rate constant on temperature is studied and the graph below is prepared from the results. The energy of activation of this reaction is kJ/mol.

At elevated temperatures, methylisonitrile (CH₃NC) isomerizes to acetonitrile (CH₃CN): CH₃NC (g) → CH₃3CN (g) The reaction is first order in methylisonitrile. The attached graph shows data for the reaction obtained at 198.9°C. The rate constant for the reaction is s^-¹.

The data in the table below were obtained for the reaction: 2 ClO₂(aq) + 2 OH^-(aq) → ClO₃^-(aq) + ClO₂^-(aq) + H₂O (1) -What is the overall order of the reaction?

A second- order reaction has a half- life of 18 s when the initial concentration of reactant is 0.71 M. The rate constant for this reaction is M^-¹s^-¹.

The reaction A (aq) - B (aq) is first order in [A]. A solution is prepared with [A] = 1.22 M. The following data are obtained as the reaction proceeds: The rate constant for this reaction is s^-¹.