Question 1

Carbon dating may be used to date (once living) materials that are between 100 and 40,000 years old. The half-life of the first-order decay of carbon-14 is 5730 years. What percentage of carbon-14 remains in a sample after 40,000 years.

Accepted Answer

The answer of Carbon dating may be used to date...

Question 2

Hydrogen peroxide decomposes into water and oxygen in a first-order process. H2O2(aq)  ? H2O(  ℓ\ellℓ  )  + 1/2 O2(g) 
At 20.0 °C, the half-life for the reaction is 3.92 × 104 seconds. If the initial concentration of hydrogen peroxide is 0.52 M, what is the concentration after 7.00 days?

Accepted Answer

A)   1.2 × 10-5 M
B)   0.034 M
C)   0.074 M
D)   0.22 M
E)   0.52 M F) A) and C)
G) B) and D)

Question 3

For the second-order reaction below, the initial concentration of reactant A is 0.24 M. If the rate constant for the reaction is 1.5 × 10-2 M-1s-1, what is the concentration of A after 265 seconds? 2A → B + C
Rate = k[A]2

Accepted Answer

A)   0.12 M
B)   0.19 M
C)   0.95 M
D)   4.0 M
E)   5.2 MF) None of the above
G) A) and B)

Question 4

The reaction kinetics for a certain reaction are studied over several temperatures. Which of the following is/are not effected by a change in reaction temperature?

Accepted Answer

A)   the reaction rate
B)   the rate constant, k
C)   the energy of activation, Ea
D)   a and b
E)   a, b, and cF) A) and E)
G) B) and D)

Question 5

For the overall reaction A + 2B ? C, which of the following mechanisms yields the correct overall chemical equation and is consistent with the rate equation below? Rate = k[A][B]

Accepted Answer

A)   A + B  ⇌\rightleftharpoons⇌  I (fast) I + A ? C (slow) 
B)   A + B ? I (slow) I + B ? C (fast) 
C)   2B ? I (slow) A + I ? C (fast) 
D)   2B  ⇌\rightleftharpoons⇌  I (fast) I + A ? C (slow) 
E)   A + 2B  ⇌\rightleftharpoons⇌  I (fast) I + B ? C + B (slow)  F) None of the above
G) B) and C)

Question 6

The reaction of NO and O2 produces 
NO2. 2 NO(g)  + O2(g)  ? 2 NO2(g) 
The reaction is second-order with respect to NO(g)  and first-order with respect to O2(g) . At a given temperature, the rate constant, k, equals 4.7 × 102 M-2s-1. What is the rate of reaction when the initial concentrations of NO and O2 are 0.025 M and 0.015 M, respectively?

Accepted Answer

A)   2.6 × 10-3 M/s
B)   4.4 × 10-3 M/s
C)   0.18 M/s
D)   2.0 × 10-8 M/s
E)   3.8 × 102 M/sF) A) and E)
G) A) and D)

Question 7

For a certain overall second-order reaction with the general form aA → products, the initial rate of reaction is 0.50 M·s−1 when the initial concentration of the reactant is 0.27 M. What is the rate constant for this reaction?

Accepted Answer

A)   0.039 M-1·s−1
B)   6.9 M-1·s−1
C)   0.50 M-1·s−1
D)   0.54 M-1·s−1
E)   25 M-1·s−1F) B) and D)
G) All of the above

Question 8

The rate constant of a first-order decomposition reaction is 0.0147 s-1. If the initial concentration of reactant is 0.178 M, what is the concentration of reactant after 30.0 seconds?

Accepted Answer

A)   8.72 × 105 M
B)   0.0645 M
C)   0.115 M
D)   0.0785 M
E)   0.643 MF) A) and C)
G) A) and E)

Question 9

Which of the given relationships correctly compares the rates of the reactants and products for the reaction below? 
2 NOCl(g)  ? 2 NO(g)  + Cl2(g)

Accepted Answer

A)    −Δ[NOCl]Δt=Δ[NO]Δt+Δ[Cl2]Δt- \frac { \Delta [ \mathrm { NOCl } ] } { \Delta t } = \frac { \Delta [ \mathrm { NO } ] } { \Delta t } + \frac { \Delta \left[ \mathrm { Cl } _ { 2 } \right] } { \Delta t }−ΔtΔ[NOCl]​=ΔtΔ[NO]​+ΔtΔ[Cl2​]​ 
B)    Δ[NOCl]Δt=Δ[NO]Δt=Δ[Cl2]Δt\frac { \Delta [ \mathrm { NOCl } ] } { \Delta t } = \frac { \Delta [ \mathrm { NO } ] } { \Delta t } = \frac { \Delta \left[ \mathrm { Cl } _ { 2 } \right] } { \Delta t }ΔtΔ[NOCl]​=ΔtΔ[NO]​=ΔtΔ[Cl2​]​ 
C)    −12Δ[NOCl]Δt=12Δ[NO]Δt=Δ[Cl2]Δt- \frac { 1 } { 2 } \frac { \Delta [ \mathrm { NOCl } ] } { \Delta t } = \frac { 1 } { 2 } \frac { \Delta [ \mathrm { NO } ] } { \Delta t } = \frac { \Delta \left[ \mathrm { Cl } _ { 2 } \right] } { \Delta t }−21​ΔtΔ[NOCl]​=21​ΔtΔ[NO]​=ΔtΔ[Cl2​]​ 
D)    −2Δ[NOCl]Δt=2Δ[NO]Δt=Δ[Cl2]Δt\frac { - 2 \Delta [ \mathrm { NOCl } ] } { \Delta t } = \frac { 2 \Delta [ \mathrm { NO } ] } { \Delta t } = \frac { \Delta \left[ \mathrm { Cl } _ { 2 } \right] } { \Delta t }Δt−2Δ[NOCl]​=Δt2Δ[NO]​=ΔtΔ[Cl2​]​ 
E)    Δ[NOCl]Δt=ΔtΔ[NO]=ΔtΔ[Cl2]\frac { \Delta [ \mathrm { NOCl } ] } { \Delta t } = \frac { \Delta t } { \Delta [ \mathrm { NO } ] } = \frac { \Delta t } { \Delta \left[ \mathrm { Cl } _ { 2 } \right] }ΔtΔ[NOCl]​=Δ[NO]Δt​=Δ[Cl2​]Δt​F) None of the above
G) B) and E)

Question 10

What is the half-life of the first-order reaction if it takes 4.4 × 10-2 seconds for a concentration to decrease from 0.50 M to 0.20 M?

Accepted Answer

A)   2.5 × 10-2 s
B)   3.3 × 10-2 s
C)   1.6 s
D)   21 s
E)   27 sF) D) and E)
G) B) and D)

Question 11

For the reaction A ? B + C, which of the following equations corresponds to the integrated expression for a second-order decomposition reaction?

Accepted Answer

A)    [A]t=−kt+[A]0[ \mathrm { A } ] _ { t } = - k t + [ \mathrm { A } ] _ { 0 }[A]t​=−kt+[A]0​ 
B)    ln⁡[A]t[ A]0=−kt\ln \frac { [ \mathrm { A } ] _ { t } } { [ \mathrm {~A} ] _ { 0 } } = - k tln[ A]0​[A]t​​=−kt 
C)    ln⁡[A]t=ln⁡[−kt]+ln⁡[A]0\ln [ \mathrm { A } ] _ { t } = \ln [ - k t ] + \ln [ \mathrm { A } ] _ { 0 }ln[A]t​=ln[−kt]+ln[A]0​ 
D)    [A]t[ A]0=−kt\frac { [ \mathrm { A } ] _ { t } } { [ \mathrm {~A} ] _ { 0 } } = - k t[ A]0​[A]t​​=−kt 
E)    1[ A]t=kt+1[ A]0\frac { 1 } { [ \mathrm {~A} ] _ { t } } = k t + \frac { 1 } { [ \mathrm {~A} ] _ { 0 } }[ A]t​1​=kt+[ A]0​1​F) B) and C)
G) B) and E)

Question 12

Which of the following statements is correct for the first-order reaction: A → 2B?

Accepted Answer

A)   The concentration of A decreases linearly with respect to time.
B)   The concentration of A is constant with respect to time.
C)   The natural logarithm of the concentration of A decreases linearly with respect to time.
D)   The rate of reaction is constant with respect to time.
E)   The rate constant, k, of the reaction decreases linearly with respect to time.F) C) and D)
G) B) and C)

Question 13

Termolecular elementary steps are rare. Why?

Accepted Answer

A termolecular elementary step requires ...

Question 14

Which of the following statements is true of the Arrhenius equation?

Accepted Answer

A)   The factor  e−Ea/RTe ^ { - E a / R T }e−Ea/RT  always has a value more than 1.
B)   Ea represents the fraction of molecules having the minimum energy required for a reaction.
C)   It can be used to calculate Ea from the temperature dependence of the rate constant.
D)   It can be used to calculate the rate constant if  e−Ea/RTe ^ { - E a / R T }e−Ea/RT  is known.
E)   The factor  e−Ea/RTe ^ { - E a / R T }e−Ea/RT  always has a value more than 10. F) C) and D)
G) B) and D)

Exam 15: Chemical Kinetics: the Rates of Chemical Reactions

For the overall reaction A + 2B ? C, which of the following mechanisms yields the correct overall chemical equation and is consistent with the rate equation below? Rate = k[A][B]

Correct Answer
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For the second-order reaction below, the initial concentration of reactant A is 0.24 M. If the rate constant for the reaction is 1.5 × 10^-2 M^-1s^-1, what is the concentration of A after 265 seconds? 2A → B + C Rate = k[A]²

Correct Answer
verified

The reaction kinetics for a certain reaction are studied over several temperatures. Which of the following is/are not effected by a change in reaction temperature?

Correct Answer
verified

Which of the given relationships correctly compares the rates of the reactants and products for the reaction below? 2 NOCl(g) ? 2 NO(g) + Cl₂(g)

Correct Answer
verified

The rate constant of a first-order decomposition reaction is 0.0147 s^-1. If the initial concentration of reactant is 0.178 M, what is the concentration of reactant after 30.0 seconds?

Correct Answer
verified

Termolecular elementary steps are rare. Why?

Correct Answer
verified
A termolecular elementary step requires ...
View Answer

For a certain overall second-order reaction with the general form aA → products, the initial rate of reaction is 0.50 M·s−1 when the initial concentration of the reactant is 0.27 M. What is the rate constant for this reaction?

Correct Answer
verified

Correct Answer
verified

Hydrogen peroxide decomposes into water and oxygen in a first-order process. H₂O₂(aq) ? H₂O( $\ell$ ) + 1/2 O₂(g) At 20.0 °C, the half-life for the reaction is 3.92 × 10⁴ seconds. If the initial concentration of hydrogen peroxide is 0.52 M, what is the concentration after 7.00 days?

Correct Answer
verified

Carbon dating may be used to date (once living) materials that are between 100 and 40,000 years old. The half-life of the first-order decay of carbon-14 is 5730 years. What percentage of carbon-14 remains in a sample after 40,000 years.

Correct Answer
verified

What is the half-life of the first-order reaction if it takes 4.4 × 10^-2 seconds for a concentration to decrease from 0.50 M to 0.20 M?

Correct Answer
verified

Which of the following statements is true of the Arrhenius equation?

Correct Answer
verified

Which of the following statements is correct for the first-order reaction: A → 2B?

Correct Answer
verified

For the reaction A ? B + C, which of the following equations corresponds to the integrated expression for a second-order decomposition reaction?

Correct Answer
verified

Exam 15: Chemical Kinetics: the Rates of Chemical Reactions

For the overall reaction A + 2B ? C, which of the following mechanisms yields the correct overall chemical equation and is consistent with the rate equation below? Rate = k[A][B]

Correct AnswerverifiedShow Answer

For the second-order reaction below, the initial concentration of reactant A is 0.24 M. If the rate constant for the reaction is 1.5 × 10-2 M-1s-1, what is the concentration of A after 265 seconds? 2A → B + C Rate = k[A]2

Correct AnswerverifiedShow Answer

The reaction kinetics for a certain reaction are studied over several temperatures. Which of the following is/are not effected by a change in reaction temperature?

Correct AnswerverifiedShow Answer

Which of the given relationships correctly compares the rates of the reactants and products for the reaction below? 2 NOCl(g) ? 2 NO(g) + Cl2(g)

Correct AnswerverifiedShow Answer

The rate constant of a first-order decomposition reaction is 0.0147 s-1. If the initial concentration of reactant is 0.178 M, what is the concentration of reactant after 30.0 seconds?

Correct AnswerverifiedShow Answer

Termolecular elementary steps are rare. Why?

Correct AnswerverifiedA termolecular elementary step requires ...View AnswerShow Answer

For a certain overall second-order reaction with the general form aA → products, the initial rate of reaction is 0.50 M·s−1 when the initial concentration of the reactant is 0.27 M. What is the rate constant for this reaction?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Hydrogen peroxide decomposes into water and oxygen in a first-order process. H2O2(aq) ? H2O( ℓ\ellℓ ) + 1/2 O2(g) At 20.0 °C, the half-life for the reaction is 3.92 × 104 seconds. If the initial concentration of hydrogen peroxide is 0.52 M, what is the concentration after 7.00 days?

Correct AnswerverifiedShow Answer

Carbon dating may be used to date (once living) materials that are between 100 and 40,000 years old. The half-life of the first-order decay of carbon-14 is 5730 years. What percentage of carbon-14 remains in a sample after 40,000 years.

Correct AnswerverifiedShow Answer

What is the half-life of the first-order reaction if it takes 4.4 × 10-2 seconds for a concentration to decrease from 0.50 M to 0.20 M?

Correct AnswerverifiedShow Answer

Which of the following statements is true of the Arrhenius equation?

Correct AnswerverifiedShow Answer

Which of the following statements is correct for the first-order reaction: A → 2B?

Correct AnswerverifiedShow Answer

For the reaction A ? B + C, which of the following equations corresponds to the integrated expression for a second-order decomposition reaction?

Correct AnswerverifiedShow Answer

Correct Answer
verified

For the second-order reaction below, the initial concentration of reactant A is 0.24 M. If the rate constant for the reaction is 1.5 × 10^-2 M^-1s^-1, what is the concentration of A after 265 seconds? 2A → B + C Rate = k[A]²

Correct Answer
verified

Correct Answer
verified

Which of the given relationships correctly compares the rates of the reactants and products for the reaction below? 2 NOCl(g) ? 2 NO(g) + Cl₂(g)

Correct Answer
verified

The rate constant of a first-order decomposition reaction is 0.0147 s^-1. If the initial concentration of reactant is 0.178 M, what is the concentration of reactant after 30.0 seconds?

Correct Answer
verified

Correct Answer
verified
A termolecular elementary step requires ...
View Answer

Correct Answer
verified

Correct Answer
verified

Hydrogen peroxide decomposes into water and oxygen in a first-order process. H₂O₂(aq) ? H₂O( $\ell$ ) + 1/2 O₂(g) At 20.0 °C, the half-life for the reaction is 3.92 × 10⁴ seconds. If the initial concentration of hydrogen peroxide is 0.52 M, what is the concentration after 7.00 days?

Correct Answer
verified

Correct Answer
verified

What is the half-life of the first-order reaction if it takes 4.4 × 10^-2 seconds for a concentration to decrease from 0.50 M to 0.20 M?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified