Question 1

Which is the correct unit for a zeroth-order rate constant?

Accepted Answer

A)  s-1 
B)  M • s-1 
C)  M • s 
D)  M-1 • s-1 
E)  M-2 • s-1 
A)  s-1 
B)  M • s-1 
C)  M • s 
D)  M-1 • s-1 
E)  M-2 • s-1 B

Question 2

Cyclopropane is converted to propene in a first-order process. The rate constant is 5.4 × 10-2 h-1. If the initial concentration of cyclopropane is 0.150 M, what will its concentration be after 22.0 hours?

Accepted Answer

A)  0.046 M 
B)  0.11 M 
C)  0.13 M 
D)  0.49 M 
E)  0.054 M 
A)  0.046 M 
B)  0.11 M 
C)  0.13 M 
D)  0.49 M 
E)  0.054 M A

Question 3

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

Accepted Answer

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

Question 4

What are possible units for the rate of a reaction?

Accepted Answer

A)  L • mol-1 • s-1 
B)  L2 • mol-2 • s-1 
C)  s-1 
D)  s-2 
E)  mol • L-1 • s-1 
A)  L • mol-1 • s-1 
B)  L2 • mol-2 • s-1 
C)  s-1 
D)  s-2 
E)  mol • L-1 • s-1

Question 5

The reaction A + 2B → Products was found to have the rate law, rate = k[A][B]2. Predict by what factor the rate of reaction will increase when the concentration of A is doubled and the concentration of B is also doubled.

Accepted Answer

A)  2 
B)  4 
C)  6 
D)  8 
E)  9 
A)  2 
B)  4 
C)  6 
D)  8 
E)  9

Question 6

A ________-________ is a reaction whose rate depends on the concentration of one of the reactants squared.

Accepted Answer

second-ord

Question 7

In the collision theory of reaction rates, the rate constant for a bimolecular reaction can be written as
k = A•exp(-Ea/RT)
Briefly explain the physical meaning (interpretation) of the following factors which appear in the above expression:
a. A
b. exp(-Ea/RT)

Accepted Answer

a. the collision frequency or

Question 8

Nitric oxide gas (NO) reacts with chlorine gas according to the equation NO +   Cl2 → NOCl.
The following initial rates of reaction have been measured for the given reagent concentrations.   Which of the following is the rate law for this reaction?

Accepted Answer

A)  rate = k[NO] 
B)  rate = k[NO][Cl2]1/2 
C)  rate = k[NO][Cl2] 
D)  rate = k[NO]2[Cl2] 
E)  rate = k[NO]2[Cl2]2 
A)  rate = k[NO] 
B)  rate = k[NO][Cl2]1/2 
C)  rate = k[NO][Cl2] 
D)  rate = k[NO]2[Cl2] 
E)  rate = k[NO]2[Cl2]2

Question 9

For a zeroth-order reaction, if the concentration of reactant A 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 10

Carbon-14 is a radioactive isotope which decays with a half-life of 5730 years. What is the first-order rate constant for its decay?

Accepted Answer

A)  5.25 × 10-5 yr-1 
B)  1.21 × 10-4 yr-1 
C)  1.75 × 10-4 yr-1  
D)  3.49 × 10-4 yr-1 
E)  3.97 × 103 yr-1 
A)  5.25 × 10-5 yr-1 
B)  1.21 × 10-4 yr-1 
C)  1.75 × 10-4 yr-1  
D)  3.49 × 10-4 yr-1 
E)  3.97 × 103 yr-1

Question 11

The first-order reaction SO2Cl2→ SO2 + Cl2 is 10% complete in 80. min. How long would it take for the reaction to be 95% complete?

Accepted Answer

A)  1.8 min 
B)  104 min 
C)  530 min 
D)  2300 min 
E)  990 min 
A)  1.8 min 
B)  104 min 
C)  530 min 
D)  2300 min 
E)  990 min

Question 12

For the reaction 3A(g) + 2B(g) → 2C(g) + 2D(g)
The following data were collected at constant temperature. Determine the correct rate law for this reaction.

Accepted Answer

A)  Rate = k[A][B] 
B)  Rate = k[A][B]2 
C)  Rate = k[A]3[B]2 
D)  Rate = k[A]1.5[B] 
E)  Rate = k[A]2[B] 
A)  Rate = k[A][B] 
B)  Rate = k[A][B]2 
C)  Rate = k[A]3[B]2 
D)  Rate = k[A]1.5[B] 
E)  Rate = k[A]2[B]

Question 13

The reaction A + 2B → Products was found to follow the rate law: rate = k[A]2[B]. Predict by what factor the rate of reaction will increase when the concentration of A is doubled, the concentration of B is tripled, and the temperature remains constant.

Accepted Answer

A)  5 
B)  6 
C)  12 
D)  18 
E)  None of these 
A)  5 
B)  6 
C)  12 
D)  18 
E)  None of these

Question 14

Consider the following potential energy profile for the A → B reaction. How many elementary steps are there?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 15

Which of the following is the correct unit for a second-order rate constant?

Accepted Answer

A)  s-1 
B)  M • s-1 
C)  M • s 
D)  M -1 • s-1 
E)  M -2 • s-1 
A)  s-1 
B)  M • s-1 
C)  M • s 
D)  M -1 • s-1 
E)  M -2 • s-1

Question 16

The data below were determined for the reaction S2O82-(aq) + 3I-(aq) → 2SO42-(aq) + I3-(aq).   Which rate law is consistent with the experimental data for this reaction?

Accepted Answer

A)  rate = k[S2O82- ][I -]3 
B)  rate = k[S2O82-] 
C)  rate = k[S2O82-]2[I -]2 
D)  rate = k[I -] 
E)  rate = k[S2O82-][I -] 
A)  rate = k[S2O82- ][I -]3 
B)  rate = k[S2O82-] 
C)  rate = k[S2O82-]2[I -]2 
D)  rate = k[I -] 
E)  rate = k[S2O82-][I -]

Question 17

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 yr-1. What fraction of the tritium initially in a sample is still present 30. years later?

Accepted Answer

A)  0.19 
B)  0.60 
C)  0.15 
D)  2.8 × 10-38 
E)  0.81 
A)  0.19 
B)  0.60 
C)  0.15 
D)  2.8 × 10-38 
E)  0.81

Question 18

The oxidation of iodide ions by arsenic acid in acidic aqueous solution occurs according to the net reaction H3AsO4 + 3I - + 2H3O +→ H3AsO3 + I3- + 3H2O. The experimental rate law for this reaction is
Rate = k [H3AsO4] [I-] [H3O+].
According to the rate law for the reaction, an increase in the concentration of hydronium ion has what effect on this reaction?

Accepted Answer

The rate o

Question 19

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

Question 20

The elementary step of the reaction mechanism which only involves one reactant is called ________.

Accepted Answer

The answer of The elementary step of the reaction mechanism...

Exam 14: Chemical Kinetics

Which is the correct unit for a zeroth-order rate constant?

Cyclopropane is converted to propene in a first-order process. The rate constant is 5.4 × 10-2 h-1. If the initial concentration of cyclopropane is 0.150 M, what will its concentration be after 22.0 hours?

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

What are possible units for the rate of a reaction?

The reaction A + 2B → Products was found to have the rate law, rate = k[A][B]2. Predict by what factor the rate of reaction will increase when the concentration of A is doubled and the concentration of B is also doubled.

A ________-________ is a reaction whose rate depends on the concentration of one of the reactants squared.

In the collision theory of reaction rates, the rate constant for a bimolecular reaction can be written as k = A•exp(-Ea/RT) Briefly explain the physical meaning (interpretation) of the following factors which appear in the above expression: a. A b. exp(-Ea/RT)

Nitric oxide gas (NO) reacts with chlorine gas according to the equation NO + Cl2 → NOCl. The following initial rates of reaction have been measured for the given reagent concentrations. Which of the following is the rate law for this reaction?

For a zeroth-order reaction, if the concentration of reactant A is plotted vs. time, which corresponds to the slope of this plot?

Carbon-14 is a radioactive isotope which decays with a half-life of 5730 years. What is the first-order rate constant for its decay?

The first-order reaction SO2Cl2→ SO2 + Cl2 is 10% complete in 80. min. How long would it take for the reaction to be 95% complete?

For the reaction 3A(g) + 2B(g) → 2C(g) + 2D(g) The following data were collected at constant temperature. Determine the correct rate law for this reaction.

The reaction A + 2B → Products was found to follow the rate law: rate = k[A]2[B]. Predict by what factor the rate of reaction will increase when the concentration of A is doubled, the concentration of B is tripled, and the temperature remains constant.

Consider the following potential energy profile for the A → B reaction. How many elementary steps are there?

Which of the following is the correct unit for a second-order rate constant?

The data below were determined for the reaction S2O82-(aq) + 3I-(aq) → 2SO42-(aq) + I3-(aq). Which rate law is consistent with the experimental data for this reaction?

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 yr-1. What fraction of the tritium initially in a sample is still present 30. years later?

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?

The elementary step of the reaction mechanism which only involves one reactant is called ________.

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Cyclopropane is converted to propene in a first-order process. The rate constant is 5.4 × 10^-2 h^-1. If the initial concentration of cyclopropane is 0.150 M, what will its concentration be after 22.0 hours?

The reaction A + 2B → Products was found to have the rate law, rate = k[A][B]². Predict by what factor the rate of reaction will increase when the concentration of A is doubled and the concentration of B is also doubled.

A - is a reaction whose rate depends on the concentration of one of the reactants squared.

In the collision theory of reaction rates, the rate constant for a bimolecular reaction can be written as k = A•exp(-E_a/RT) Briefly explain the physical meaning (interpretation) of the following factors which appear in the above expression: a. A b. exp(-E_a/RT)

Nitric oxide gas (NO) reacts with chlorine gas according to the equation NO + Cl₂→ NOCl. The following initial rates of reaction have been measured for the given reagent concentrations. Which of the following is the rate law for this reaction?

The first-order reaction SO₂Cl₂→ SO₂ + Cl₂ is 10% complete in 80. min. How long would it take for the reaction to be 95% complete?

The reaction A + 2B → Products was found to follow the rate law: rate = k[A]²[B]. Predict by what factor the rate of reaction will increase when the concentration of A is doubled, the concentration of B is tripled, and the temperature remains constant.

The data below were determined for the reaction S₂O₈^2-(aq) + 3I^-(aq) → 2SO₄^2-(aq) + I₃^-(aq). Which rate law is consistent with the experimental data for this reaction?

The radioactive isotope tritium decays with a first-order rate constant k of 0.056 yr^-1. What fraction of the tritium initially in a sample is still present 30. years later?

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?