Question 1

The rate of a reaction is determined by the rate of the fastest step in the mechanism.

Accepted Answer

A) True 
 B)False

Question 2

Is a bimolecular reaction necessarily second-order? Is a second order reaction necessarily bimolecular? Answer,with explanations and clarifications.

Accepted Answer

For elementary reactions,the order follo...

Question 3

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 4

A transition state is a species (or state)corresponding to an energy maximum on a reaction energy diagram.

Accepted Answer

A) True 
 B)False

Question 5

A certain first-order reaction A → B is 25% complete in 42 min at 25°C.What is the half-life of the reaction?

Accepted Answer

A)  21 min
B)  42 min
C)  84 min
D)  120 min
E)  101 minF) D) and E)
G) C) and E)

Question 6

What rate constant can be determined from only the half-life of a reaction?

Accepted Answer

A)  Zeroth
B)  First
C)  Second
D)  Third
E)  The rate constant cannot be determined using only a rate constant for any reaction.F) A) and C)
G) C) and D)

Question 7

Consider the following potential energy profile for the A → B reaction.The overall reaction is________.

Accepted Answer

A)  endothermic
B)  exothermicC) A) and B)
D) undefined

Question 8

The rate law predicted by the following two-step mechanism is Rate = k[A][B].
A → C + B (slow)
A + B → C + E (fast)

Accepted Answer

A) True 
 B)False

Question 9

According to the ___________ ________ of chemical kinetics,the reaction rate is directly proportional to the number of molecular collisions per second.

Accepted Answer

The answer of According to the ___________ ________ of chemical...

Question 10

Butadiene,C4H6 (used to make synthetic rubber and latex paints) .dimerizes to C8H12 with a rate law of rate = 0.014 L/mol• s [C4H6]2.What will be the concentration of C4H6 after 3.0 hours if the initial concentration is 0.025 M?

Accepted Answer

A)  0.0052 M
B)  0.024 M
C)  43 M
D)  190 M
E)  0.0000 MF) B) and E)
G) None of the above

Question 11

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

Accepted Answer

A) True 
 B)False

Question 12

For the reaction A + 2B → C,which expression is correct?

Accepted Answer

A)  Δ[C]/Δt = Δ[A]/Δt
B)  Δ[C]/Δt = 2Δ[B]/Δt
C)  Δ[C]/Δt = -2Δ[B]/Δt
D)  Δ[C]/Δt = -½Δ[B]/Δt
E)  Δ[C]/Δt = -½Δ[A]/ΔtF) B) and C)
G) A) and E)

Question 13

Enzymes are _______ .

Accepted Answer

A)  large carbohydrate molecules
B)  also called substrates
C)  usually heterogeneous catalysts
D)  insensitive to temperature
E)  biological catalystsF) All of the above
G) C) and D)

Question 14

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

Question 15

According to the collision theory of reaction rates,what are the three requirements which must be met before an elementary reaction between two molecules can occur?

Accepted Answer

Molecules must collide with ea...

Question 16

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-1F) A) and D)
G) D) and E)

Question 17

Consider the following potential energy profile for the A → B reaction.How many intermediates are formed?

Accepted Answer

A)  1
B)  2
C)  3
D)  4
E)  5F) B) and D)
G) A) and E)

Question 18

The rate law for the reaction 3A → 2B is rate = k[A] with a rate constant of 0.0447 h-1.What is the half-life of the reaction?

Accepted Answer

A)  0.0224 h
B)  0.0645 h
C)  15.5 h
D)  22.4 h
E)  44.7 hF) A) and D)
G) A) and C)

Question 19

What are possible units for the reaction rate?

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-1F) B) and E)
G) B) and D)

Question 20

The reaction 2NO2(g) → 2NO(g) + O2(g) is suspected to be second order in NO2.Which of the following kinetic plots would be the most useful to confirm whether or not the reaction is second order?

Accepted Answer

A)  A plot of [NO2]-1 vs.t
B)  A plot of ln [NO2] vs.t
C)  A plot of [NO2] vs.t
D)  A plot of ln [NO2]-1 vs.t
E)  A plot of [NO2]2 vs.tF) C) and D)
G) A) and B)

Exam 14: Chemical Kinetics

What rate constant can be determined from only the half-life of a reaction?

Correct AnswerverifiedShow Answer

Consider the following potential energy profile for the A → B reaction.The overall reaction is________.

Correct AnswerverifiedShow Answer

Is a bimolecular reaction necessarily second-order? Is a second order reaction necessarily bimolecular? Answer,with explanations and clarifications.

Correct AnswerverifiedFor elementary reactions,the order follo...View AnswerShow Answer

For the reaction A + 2B → C,which expression is correct?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What are possible units for the reaction rate?

Correct AnswerverifiedShow Answer

According to the collision theory of reaction rates,what are the three requirements which must be met before an elementary reaction between two molecules can occur?

Correct AnswerverifiedMolecules must collide with ea...View AnswerShow Answer

A certain first-order reaction A → B is 25% complete in 42 min at 25°C.What is the half-life of the reaction?

Correct AnswerverifiedShow Answer

Consider the following potential energy profile for the A → B reaction.How many intermediates are formed?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedShow Answer

Butadiene,C4H6 (used to make synthetic rubber and latex paints) .dimerizes to C8H12 with a rate law of rate = 0.014 L/mol• s [C4H6]2.What will be the concentration of C4H6 after 3.0 hours if the initial concentration is 0.025 M?

Correct AnswerverifiedShow Answer

The rate law predicted by the following two-step mechanism is Rate = k[A][B]. A → C + B (slow) A + B → C + E (fast)

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A transition state is a species (or state)corresponding to an energy maximum on a reaction energy diagram.

Correct AnswerverifiedShow Answer

Enzymes are _______ .

Correct AnswerverifiedShow Answer

The reaction 2NO2(g) → 2NO(g) + O2(g) is suspected to be second order in NO2.Which of the following kinetic plots would be the most useful to confirm whether or not the reaction is second order?

Correct AnswerverifiedShow Answer

The rate law for the reaction 3A → 2B is rate = k[A] with a rate constant of 0.0447 h-1.What is the half-life of the reaction?

Correct AnswerverifiedShow Answer

According to the ___________ ________ of chemical kinetics,the reaction rate is directly proportional to the number of molecular collisions per second.

Correct AnswerverifiedShow Answer

The rate of a reaction is determined by the rate of the fastest step in the mechanism.

Correct AnswerverifiedShow Answer

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For elementary reactions,the order follo...
View Answer

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Correct Answer
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Molecules must collide with ea...
View Answer

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Correct Answer
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Butadiene,C₄H₆ (used to make synthetic rubber and latex paints) .dimerizes to C₈H₁₂ with a rate law of rate = 0.014 L/mol• s [C₄H₆]².What will be the concentration of C₄H₆ after 3.0 hours if the initial concentration is 0.025 M?

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Correct Answer
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The reaction 2NO₂(g) → 2NO(g) + O₂(g) is suspected to be second order in NO₂.Which of the following kinetic plots would be the most useful to confirm whether or not the reaction is second order?

Correct Answer
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The rate law for the reaction 3A → 2B is rate = k[A] with a rate constant of 0.0447 h^-1.What is the half-life of the reaction?

Correct Answer
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According to the ___ of chemical kinetics,the reaction rate is directly proportional to the number of molecular collisions per second.

Correct Answer
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Correct Answer
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