Question 1

For a second-order reaction, if [A]-1 is plotted vs. time, which corresponds to the slope of this plot?

Accepted Answer

A)  1/[A] 
B)  k 
C)  1/k 
D)  ln[A] 
E)  -k 
A)  1/[A] 
B)  k 
C)  1/k 
D)  ln[A] 
E)  -k

Question 2

The isomerization of cyclopropane follows first-order kinetics. The rate constant at 700. K is 6.20 × 10-4 min-1, and the half-life at 760. K is 29.0 min. What is the activation energy for this reaction? (R = 8.314 J/mol• K)

Accepted Answer

A)  5.07 kJ/mol 
B)  27.0 kJ/mol 
C)  50.7 kJ/mol 
D)  160. kJ/mol 
E)  269 kJ/mol 
A)  5.07 kJ/mol 
B)  27.0 kJ/mol 
C)  50.7 kJ/mol 
D)  160. kJ/mol 
E)  269 kJ/mol

Question 3

For each of the following terms/concepts, give a brief explanation or definition.
a. order of a reaction
b. elementary reaction
c. reaction intermediate

Accepted Answer

a. Order refers to the power to which th

Question 4

What statement below best describes the graph representing the integrated second-order rate law?

Accepted Answer

A)  A plot of [A]t vs. t yields a straight line with a negative slope equal to -k. 
B)  A plot of 1/[A]t vs. t yields a straight line with a negative slope equal to k. 
C)  A plot of ln[A]t vs. t yields a straight line with a positive slope equal to -k. 
D)  A plot of ln[A]t vs. t yields a straight line with a negative slope equal to -k. 
E)  A plot of 1/[A]t vs. t yields a straight line with a positive slope equal to k. 
A)  A plot of [A]t vs. t yields a straight line with a negative slope equal to -k. 
B)  A plot of 1/[A]t vs. t yields a straight line with a negative slope equal to k. 
C)  A plot of ln[A]t vs. t yields a straight line with a positive slope equal to -k. 
D)  A plot of ln[A]t vs. t yields a straight line with a negative slope equal to -k. 
E)  A plot of 1/[A]t vs. t yields a straight line with a positive slope equal to k.

Question 5

The rate law for the reaction H2O2 + 2H+ + 2I- → I2 + 2H2O is rate = k[H2O2][I-]. The following mechanism has been suggested. H2O2 + I- → HOI + OH- (slow)
OH- + H+ → H2O (fast)
HOI + H+ + I- → I2 + H2O (fast)
Identify all intermediates included in this mechanism.

Accepted Answer

A)  H+and I- 
B)  H+ and HOI 
C)  HOI and OH-  
D)  H+only 
E)  H2O and OH- 
A)  H+and I- 
B)  H+ and HOI 
C)  HOI and OH-  
D)  H+only 
E)  H2O and OH-

Question 6

What is the half-life for a second-order reaction?

Accepted Answer

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

Question 7

What is the slope of a plot of ln k vs. 1/T for the Arrhenius equation k = Ae-(Ea/RT)?

Accepted Answer

A)  A 
B)  -k 
C)  -Ea/R 
D)  k 
E)  Ea 
A)  A 
B)  -k 
C)  -Ea/R 
D)  k 
E)  Ea

Question 8

The rate constant for a reaction is 4.65 L • mol-1 • s-1. What is the overall order of the reaction?

Accepted Answer

A)  Zero 
B)  First 
C)  Second 
D)  Third 
E)  More information is needed to determine the overall order. 
A)  Zero 
B)  First 
C)  Second 
D)  Third 
E)  More information is needed to determine the overall order.

Question 9

What is the name given to the equation that relates the rate of reaction to the concentrations of reactants?

Accepted Answer

The answer of What is the name given to the...

Question 10

The following is an Arrhenius plot of a first-order reaction. The rate constant is measured in units of s-1.   Based on this Arrhenius plot, what is the activation energy of the reaction? (R = 8.314 J/K •mol)

Accepted Answer

A)  4.0 kJ/mol 
B)  5.0 kJ/mol 
C)  40 kJ/mol 
D)  42 kJ/mol 
E)  50 kJ/mol 
A)  4.0 kJ/mol 
B)  5.0 kJ/mol 
C)  40 kJ/mol 
D)  42 kJ/mol 
E)  50 kJ/mol

Question 11

The isomerization of methyl isocyanide, CH3NC → CH3CN, follows first-order kinetics. The half-lives were found to be 161 min at 199°C and 12.5 min at 230.°C. Calculate the activation energy for this reaction. (R = 8.314 J/mol • K)

Accepted Answer

A)  6.17 × 10-3 kJ/mol 
B)  31.4 kJ/mol 
C)  78.2 kJ/mol 
D)  124 kJ/mol 
E)  163 kJ/mol 
A)  6.17 × 10-3 kJ/mol 
B)  31.4 kJ/mol 
C)  78.2 kJ/mol 
D)  124 kJ/mol 
E)  163 kJ/mol

Question 12

A reaction intermediate is a species corresponding to a local energy maximum on a reaction energy diagram.

Accepted Answer

A) True 
 B)False

Question 13

For the overall chemical reaction shown below, which one of the following statements can be rightly assumed? 2H2S(g) + O2(g) → 2S(s) + 2H2O(l)

Accepted Answer

A)  The reaction is third-order overall. 
B)  The reaction is second-order overall. 
C)  The rate law is: rate = k[H2S]2 [O2]. 
D)  The rate law is: rate = k[H2S] [O2]. 
E)  The rate law cannot be determined from the information given. 
A)  The reaction is third-order overall. 
B)  The reaction is second-order overall. 
C)  The rate law is: rate = k[H2S]2 [O2]. 
D)  The rate law is: rate = k[H2S] [O2]. 
E)  The rate law cannot be determined from the information given.

Question 14

The ________ is the equation relating the rate of the reaction to the concentration of molecule.

Accepted Answer

The answer of The ________ is the equation relating the...

Question 15

For the following reaction, ΔP(C6H14)/Δt was found to be -6.2 × 10-3 atm/s. C6H14(g) → C6H6(g) + 4H2(g)
Determine ΔP(H2)/Δt for this reaction at the same time.

Accepted Answer

A)  6.2 × 10-3 atm/s 
B)  1.6 × 10-3 atm/s 
C)  2.5 × 10-2 atm/s 
D)  -1.6 × 10-3 atm/s 
E)  -2.5 × 10-2 atm/s 
A)  6.2 × 10-3 atm/s 
B)  1.6 × 10-3 atm/s 
C)  2.5 × 10-2 atm/s 
D)  -1.6 × 10-3 atm/s 
E)  -2.5 × 10-2 atm/s

Question 16

For the chemical reaction A → B + C, a plot of [A]t versus time is found to give a straight line with a negative slope. What is the order of reaction with respect to A?

Accepted Answer

A)  Zeroth 
B)  First 
C)  Second 
D)  Third 
E)  Such a plot cannot reveal the order of the reaction. 
A)  Zeroth 
B)  First 
C)  Second 
D)  Third 
E)  Such a plot cannot reveal the order of the reaction.

Question 17

Ammonium ion (NH4+) reacts with nitrite ion (NO2-) to yield nitrogen gas and liquid water. The following initial rates of reaction have been measured for the given reactant concentrations.   Which of the following is the rate law (rate equation) for this reaction?

Accepted Answer

A)  rate = k [NH4+] [NO2-]4 
B)  rate = k [NH4+] [NO2-] 
C)  rate = k [NH4+] [NO2-]2 
D)  rate = k [NH4+]2 [NO2-] 
E)  rate = k [NH4+]1/2 [NO2-]1/4 
A)  rate = k [NH4+] [NO2-]4 
B)  rate = k [NH4+] [NO2-] 
C)  rate = k [NH4+] [NO2-]2 
D)  rate = k [NH4+]2 [NO2-] 
E)  rate = k [NH4+]1/2 [NO2-]1/4

Question 18

The intermediate in a reaction appears in the mechanism of the reaction and in the overall balanced equation.

Accepted Answer

A) True 
 B)False

Question 19

________ describes the reaction rate as being directly proportional to the number of molecular collisions per second.

Accepted Answer

The answer of ________ describes the reaction rate as being...

Question 20

When the reaction A → 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 with respect to A?

Accepted Answer

A)  Zero 
B)  First 
C)  Second 
D)  Third 
E)  More information is needed to determine the order. 
A)  Zero 
B)  First 
C)  Second 
D)  Third 
E)  More information is needed to determine the order.

Exam 14: Chemical Kinetics

For a second-order reaction, if [A]-1 is plotted vs. time, which corresponds to the slope of this plot?

The isomerization of cyclopropane follows first-order kinetics. The rate constant at 700. K is 6.20 × 10-4 min-1, and the half-life at 760. K is 29.0 min. What is the activation energy for this reaction? (R = 8.314 J/mol• K)

For each of the following terms/concepts, give a brief explanation or definition. a. order of a reaction b. elementary reaction c. reaction intermediate

What statement below best describes the graph representing the integrated second-order rate law?

The rate law for the reaction H2O2 + 2H+ + 2I- → I2 + 2H2O is rate = k[H2O2][I-]. The following mechanism has been suggested. H2O2 + I- → HOI + OH- (slow) OH- + H+ → H2O (fast) HOI + H+ + I- → I2 + H2O (fast) Identify all intermediates included in this mechanism.

What is the half-life for a second-order reaction?

What is the slope of a plot of ln k vs. 1/T for the Arrhenius equation k = Ae-(Ea/RT)?

The rate constant for a reaction is 4.65 L • mol-1 • s-1. What is the overall order of the reaction?

What is the name given to the equation that relates the rate of reaction to the concentrations of reactants?

The following is an Arrhenius plot of a first-order reaction. The rate constant is measured in units of s-1. Based on this Arrhenius plot, what is the activation energy of the reaction? (R = 8.314 J/K •mol)

The isomerization of methyl isocyanide, CH3NC → CH3CN, follows first-order kinetics. The half-lives were found to be 161 min at 199°C and 12.5 min at 230.°C. Calculate the activation energy for this reaction. (R = 8.314 J/mol • K)

A reaction intermediate is a species corresponding to a local energy maximum on a reaction energy diagram.

For the overall chemical reaction shown below, which one of the following statements can be rightly assumed? 2H2S(g) + O2(g) → 2S(s) + 2H2O(l)

The ________ is the equation relating the rate of the reaction to the concentration of molecule.

For the following reaction, ΔP(C6H14)/Δt was found to be -6.2 × 10-3 atm/s. C6H14(g) → C6H6(g) + 4H2(g) Determine ΔP(H2)/Δt for this reaction at the same time.

For the chemical reaction A → B + C, a plot of [A]t versus time is found to give a straight line with a negative slope. What is the order of reaction with respect to A?

Ammonium ion (NH4+) reacts with nitrite ion (NO2-) to yield nitrogen gas and liquid water. The following initial rates of reaction have been measured for the given reactant concentrations. Which of the following is the rate law (rate equation) for this reaction?

The intermediate in a reaction appears in the mechanism of the reaction and in the overall balanced equation.

________ describes the reaction rate as being directly proportional to the number of molecular collisions per second.

When the reaction A → 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 with respect to A?

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For a second-order reaction, if [A]^-1 is plotted vs. time, which corresponds to the slope of this plot?

The isomerization of cyclopropane follows first-order kinetics. The rate constant at 700. K is 6.20 × 10^-4min^-1, and the half-life at 760. K is 29.0 min. What is the activation energy for this reaction? (R = 8.314 J/mol• K)

The rate law for the reaction H₂O₂ + 2H⁺ + 2I^-→ I₂ + 2H₂O is rate = k[H₂O₂][I^-]. The following mechanism has been suggested. H₂O₂ + I^-→ HOI + OH^-(slow) OH^-+ H⁺→ H₂O (fast) HOI + H⁺ + I^-→ I₂ + H₂O (fast) Identify all intermediates included in this mechanism.

What is the slope of a plot of ln k vs. 1/T for the Arrhenius equation k = Ae^-(^E_a/RT)?

The rate constant for a reaction is 4.65 L • mol^-1• s^-1. What is the overall order of the reaction?

The following is an Arrhenius plot of a first-order reaction. The rate constant is measured in units of s^-1. Based on this Arrhenius plot, what is the activation energy of the reaction? (R = 8.314 J/K •mol)

The isomerization of methyl isocyanide, CH₃NC → CH₃CN, follows first-order kinetics. The half-lives were found to be 161 min at 199°C and 12.5 min at 230.°C. Calculate the activation energy for this reaction. (R = 8.314 J/mol• K)

For the overall chemical reaction shown below, which one of the following statements can be rightly assumed? 2H₂S(g) + O₂(g) → 2S(s) + 2H₂O(l)

For the following reaction, ΔP(C₆H₁₄)/Δt was found to be -6.2 × 10^-3 atm/s. C₆H₁₄(g) → C₆H₆(g) + 4H₂(g) Determine ΔP(H₂)/Δt for this reaction at the same time.

For the chemical reaction A → B + C, a plot of [A]_t versus time is found to give a straight line with a negative slope. What is the order of reaction with respect to A?

Ammonium ion (NH₄⁺) reacts with nitrite ion (NO₂^-) to yield nitrogen gas and liquid water. The following initial rates of reaction have been measured for the given reactant concentrations. Which of the following is the rate law (rate equation) for this reaction?

When the reaction A → 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 with respect to A?