Question 1

What is the molecularity of the following elementary reaction? NH2Cl(aq)  + OH− (aq)  → NHCl− (aq)  + H2O(l)

Accepted Answer

A)  Unimolecular
B)  Bimolecular
C)  Termolecular
D)  Tetramolecular
E)  Need to know the reaction order before molecularity can be determined.F) A) and E)
G) B) and E)

Question 2

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

Accepted Answer

A) True 
 B)False

Question 3

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

Accepted Answer

A)  −Δ[H 2O]/Δt
B)  3Δ[BrO 3 −]/Δt
C)  −5Δ[Br −]/Δt
D)  −0.6Δ[Br −]/Δt
E)  None of these choices are correct.F) B) and C)
G) A) and E)

Question 4

A catalyst accelerates a reaction because

Accepted Answer

A)  it increases the number of molecules with energy equal to or greater than the activation energy.
B)  it lowers the activation energy for the reaction.
C)  it increases the number of collisions between molecules.
D)  it increases the temperature of the molecules in the reaction.
E)  it supplies energy to reactant molecules.F) D) and E)
G) None of the above B

Question 5

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) All of the above
G) A) and E)

Question 6

The gas-phase reaction CH3NC → CH3CN has been studied in a closed vessel, and the rate equation was found to be: Rate = −Δ[CH3NC]/Δt = k[CH3NC]. Which one of the following actions is least likely to cause a change in the rate of the reaction?

Accepted Answer

A)  Lowering the temperature
B)  Adding a catalyst
C)  Using a larger initial amount of CH 3NC in the same vessel
D)  Using a bigger vessel, but the same initial amount of CH 3NC
E)  Continuously removing CH 3CN as it is formedF) B) and D)
G) B) and C)

Question 7

A rate constant obeys the Arrhenius equation, the factor A being 2.2 ×1013 s−1 and the activation energy being 150. kJ mol−1. What is the value of the rate constant at 227°C, in s−1?

Accepted Answer

A)  2.1 × 10 13 s −1
B)  6.7 × 10 −22 s −1
C)  1.5 × 10 11 s −1
D)  4.7 × 10 −3 s −1
E)  None of these choices are correct.F) A) and B)
G) B) and E)

Question 8

The decomposition of hydrogen peroxide is a first-order process with a rate constant of 1.06 × 10−3 min−1. How long will it take for the concentration of H2O2 to drop from 0.0200 M to 0.0120 M?

Accepted Answer

A)  
B)  7.55 min
C)  481 min
D)  4550 min
E)  31,400 minF) B) and D)
G) A) and D)

Question 9

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

Accepted Answer

A)  0.0457 M
B)  0.105 M
C)  0.127 M
D)  0.492 M
E)  None of these choices are correct.F) A) and B)
G) A) and C)

Question 10

Sulfuryl chloride, SO2Cl2(g) , decomposes at high temperature to form SO2(g)  and Cl2(g) . The rate constant at a certain temperature is 4.68 × 10−5s−1. 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 C)
G) A) and D)

Question 11

Sulfur trioxide can undergo decomposition according to the equation 2SO3 → 2SO2 + O2
For this reaction, rate = −0.5Δ[SO3 ]/Δt = k[SO3]2. If the reaction rate is 1.75 × 10−7 mol L−1 min−1 when the concentration of sulfur trioxide is 5.4 × 10−3 mol L−1, what is the value of the rate constant k?

Accepted Answer

A)  3.2 × 10 −5 L mol −1 min −1
B)  1.6 × 10 −5 L mol −1 min −1
C)  6.0 × 10 −3 L mol −1 min −1
D)  3.0 × 10 −3 L mol −1 min −1
E)  1.6 × 10 −2 L mol −1 min −1F) C) and D)
G) A) and D)

Question 12

In a reversible reaction, a catalyst will speed up the forward reaction but not affect the reverse reaction.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following sets of units could be appropriate for a zero-order rate constant?

Accepted Answer

A)  s −1
B)  L mol −1s −1
C)  L 2 mol −2s −1
D)  L 3 mol −3s −1
E)  mol L −1s −1F) None of the above
G) A) and E)

Question 14

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.
2 C) Rate = k[A] 3[B] 2 D) Rate = k[A] 1.5[B] E) Rate = k[A] 2[B]" class="answers-bank-image d-inline" rel="preload" >

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]F) A) and E)
G) B) and C) E

Question 15

The reaction CH3NC(g)  → CH3CN(g)  is first-order with respect to methyl isocyanide, CH3NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min−1?

Accepted Answer

A)  −0.135 min −1
B)  0.0279 min −1
C)  0.089 min −1
D)  0.135 min −1
E)  35.8 min −1F) A) and B)
G) C) and D) B

Question 16

Ammonia will react with oxygen in the presence of a copper catalyst to form nitrogen and water. From 164.5°C to 179.0°C, the rate constant increases by a factor of 4.27. What is the activation energy of this oxidation reaction?

Accepted Answer

A)  24.5 kJ/mol
B)  165 kJ/mol
C)  242 kJ/mol
D)  1630 kJ/mol
E)  > 10 4 kJ/molF) A) and E)
G) D) and E)

Question 17

When the reaction A → B + C is studied, a plot of ln[A]t vs. time gives a straight line with a negative 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 E)
G) B) and C)

Question 18

A reaction is second-order with respect to the reactant R. Which of the following plots will produce a straight line?

Accepted Answer

A)  [R] vs. 1/time
B)  1/[R] vs. time
C)  [R] 2 vs. time
D)  1/[R] 2 vs. time
E)  ln[R] vs. timeF) B) and D)
G) All of the above

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 sF) A) and B)
G) None of the above

Question 20

When a catalyst is added to a reaction mixture, it

Accepted Answer

A)  increases the rate of collisions between reactant molecules.
B)  provides reactant molecules with more energy.
C)  slows down the rate of the back reaction.
D)  provides a new pathway (mechanism) for the reaction.
E)  None of these choices are correct.F) D) and E)
G) B) and D)

Exam 16: Kinetics: Rates and Mechanisms of Chemical Reactions

What is the molecularity of the following elementary reaction? NH₂Cl(aq) + OH⁻ (aq) → NHCl⁻ (aq) + H₂O(l)

Correct Answer
verified

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

Correct Answer
verified

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

Correct Answer
verified

A catalyst accelerates a reaction because

Correct Answer
verified
B

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

The gas-phase reaction CH₃NC → CH₃CN has been studied in a closed vessel, and the rate equation was found to be: Rate = −Δ[CH₃NC]/Δt = k[CH₃NC]. Which one of the following actions is least likely to cause a change in the rate of the reaction?

Correct Answer
verified

A rate constant obeys the Arrhenius equation, the factor A being 2.2 ×10¹³ s⁻¹ and the activation energy being 150. kJ mol⁻¹. What is the value of the rate constant at 227°C, in s⁻¹?

Correct Answer
verified

The decomposition of hydrogen peroxide is a first-order process with a rate constant of 1.06 × 10⁻³ min⁻¹. How long will it take for the concentration of H₂O₂ to drop from 0.0200 M to 0.0120 M?

Correct Answer
verified

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

Correct Answer
verified

Sulfuryl chloride, SO₂Cl₂(g) , decomposes at high temperature to form SO₂(g) and Cl₂(g) . The rate constant at a certain temperature is 4.68 × 10⁻⁵s⁻¹. What is the order of the reaction?

Correct Answer
verified

Correct Answer
verified

In a reversible reaction, a catalyst will speed up the forward reaction but not affect the reverse reaction.

Correct Answer
verified

Which of the following sets of units could be appropriate for a zero-order rate constant?

Correct Answer
verified

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.

Correct Answer
verified
E

The reaction CH₃NC(g) → CH₃CN(g) is first-order with respect to methyl isocyanide, CH₃NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min⁻¹?

Correct Answer
verified
B

Ammonia will react with oxygen in the presence of a copper catalyst to form nitrogen and water. From 164.5°C to 179.0°C, the rate constant increases by a factor of 4.27. What is the activation energy of this oxidation reaction?

Correct Answer
verified

When the reaction A → B + C is studied, a plot of ln[A]_t vs. time gives a straight line with a negative slope. What is the order of the reaction?

Correct Answer
verified

A reaction is second-order with respect to the reactant R. Which of the following plots will produce a straight line?

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

When a catalyst is added to a reaction mixture, it

Correct Answer
verified

Exam 16: Kinetics: Rates and Mechanisms of Chemical Reactions

What is the molecularity of the following elementary reaction? NH2Cl(aq) + OH− (aq) → NHCl− (aq) + H2O(l)

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A catalyst accelerates a reaction because

Correct AnswerverifiedB

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

The gas-phase reaction CH3NC → CH3CN has been studied in a closed vessel, and the rate equation was found to be: Rate = −Δ[CH3NC]/Δt = k[CH3NC]. Which one of the following actions is least likely to cause a change in the rate of the reaction?

Correct AnswerverifiedShow Answer

A rate constant obeys the Arrhenius equation, the factor A being 2.2 ×1013 s−1 and the activation energy being 150. kJ mol−1. What is the value of the rate constant at 227°C, in s−1?

Correct AnswerverifiedShow Answer

The decomposition of hydrogen peroxide is a first-order process with a rate constant of 1.06 × 10−3 min−1. How long will it take for the concentration of H2O2 to drop from 0.0200 M to 0.0120 M?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Sulfuryl chloride, SO2Cl2(g) , decomposes at high temperature to form SO2(g) and Cl2(g) . The rate constant at a certain temperature is 4.68 × 10−5s−1. What is the order of the reaction?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

In a reversible reaction, a catalyst will speed up the forward reaction but not affect the reverse reaction.

Correct AnswerverifiedShow Answer

Which of the following sets of units could be appropriate for a zero-order rate constant?

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedE

The reaction CH3NC(g) → CH3CN(g) is first-order with respect to methyl isocyanide, CH3NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min−1?

Correct AnswerverifiedB

Ammonia will react with oxygen in the presence of a copper catalyst to form nitrogen and water. From 164.5°C to 179.0°C, the rate constant increases by a factor of 4.27. What is the activation energy of this oxidation reaction?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A reaction is second-order with respect to the reactant R. Which of the following plots will produce a straight line?

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

When a catalyst is added to a reaction mixture, it

Correct AnswerverifiedShow Answer

What is the molecularity of the following elementary reaction? NH₂Cl(aq) + OH⁻ (aq) → NHCl⁻ (aq) + H₂O(l)

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified
B

Correct Answer
verified

The gas-phase reaction CH₃NC → CH₃CN has been studied in a closed vessel, and the rate equation was found to be: Rate = −Δ[CH₃NC]/Δt = k[CH₃NC]. Which one of the following actions is least likely to cause a change in the rate of the reaction?

Correct Answer
verified

A rate constant obeys the Arrhenius equation, the factor A being 2.2 ×10¹³ s⁻¹ and the activation energy being 150. kJ mol⁻¹. What is the value of the rate constant at 227°C, in s⁻¹?

Correct Answer
verified

The decomposition of hydrogen peroxide is a first-order process with a rate constant of 1.06 × 10⁻³ min⁻¹. How long will it take for the concentration of H₂O₂ to drop from 0.0200 M to 0.0120 M?

Correct Answer
verified

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

Correct Answer
verified

Sulfuryl chloride, SO₂Cl₂(g) , decomposes at high temperature to form SO₂(g) and Cl₂(g) . The rate constant at a certain temperature is 4.68 × 10⁻⁵s⁻¹. What is the order of the reaction?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
E

The reaction CH₃NC(g) → CH₃CN(g) is first-order with respect to methyl isocyanide, CH₃NC. If it takes 10.3 minutes for exactly one quarter of the initial amount of methyl isocyanide to react, what is the rate constant in units of min⁻¹?

Correct Answer
verified
B

Correct Answer
verified

When the reaction A → B + C is studied, a plot of ln[A]_t vs. time gives a straight line with a negative slope. What is the order of the reaction?

Correct Answer
verified

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