Question 1

For the chemical reaction A → C, a plot of 1/[A]t versus time was found to give a straight line with a positive slope. What is the order of reaction?

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 2

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

Question 3

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+].
What is the order of the reaction with respect to I-?

Accepted Answer

Question 4

The ________ is the name given to the sequence of steps that sum to give the overall reaction.

Accepted Answer

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

Question 5

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

Accepted Answer

A) True 
 B)False

Question 6

It takes 42.0 min for the concentration of a reactant in a first-order reaction to drop from 0.45 M to 0.32 M at 25°C. How long will it take for the reaction to be 90% complete?

Accepted Answer

A)  13.0 min 
B)  86.0 min 
C)  137 min 
D)  222 min 
E)  284 min 
A)  13.0 min 
B)  86.0 min 
C)  137 min 
D)  222 min 
E)  284 min

Question 7

For the reaction 2A + B + 2C → D + E
The following initial rate data were collected at constant temperature. What is the correct rate law for this reaction?

Accepted Answer

A)  Rate = k [A][B][C] 
B)  Rate = k [A]2[B][C] 
C)  Rate = k [A]2[B][C]-1 
D)  Rate = k [A][B]2[C]-1 
E)  None of these choices is correct. 
A)  Rate = k [A][B][C] 
B)  Rate = k [A]2[B][C] 
C)  Rate = k [A]2[B][C]-1 
D)  Rate = k [A][B]2[C]-1 
E)  None of these choices is correct.

Question 8

What is the rate expression for the production of X, which is a gas, at constant volume?

Accepted Answer

A)  rate = PgVΔ[X]/RΔt 
B)  rate = -TΔ[X]/PgVΔt 
C)  rate = -PgV(Δ[X]/TΔt) 
D)  rate = (1/RT)(ΔPX/Δt) 
E)  rate = (1/RΔPX)(VT/Δt) 
A)  rate = PgVΔ[X]/RΔt 
B)  rate = -TΔ[X]/PgVΔt 
C)  rate = -PgV(Δ[X]/TΔt) 
D)  rate = (1/RT)(ΔPX/Δt) 
E)  rate = (1/RΔPX)(VT/Δt)

Question 9

The activation energy for the following reaction is 60. kJ/mol. Sn2+ + 2Co3+ → Sn4+ + 2Co2+
By what factor will the rate constant increase when the temperature is raised from 10°C to 28°C? (R = 8.314 J/mol• K)

Accepted Answer

A)  1.002 
B)  4.6 
C)  5.6 
D)  2.8 
E)  696 
A)  1.002 
B)  4.6 
C)  5.6 
D)  2.8 
E)  696

Question 10

The elementary reaction HBr(g) + Br(g) → H(g) + Br2 (g) is endothermic.
Would you expect the rate constant for the back reaction to be smaller or larger than that for the forward reaction? Explain, briefly.

Accepted Answer

The back reaction is exothermic. Since t

Question 11

A catalyst increases the rate of the reaction and is recovered completely at the end of the reaction.

Accepted Answer

A) True 
 B)False

Question 12

A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?

Accepted Answer

A)  0.94 
B)  0.88 
C)  0.75 
D)  0.13 
E)  0.063 
A)  0.94 
B)  0.88 
C)  0.75 
D)  0.13 
E)  0.063

Question 13

What is the activation energy for a reaction if k = 1.89 × 10-8 s-1 at 540. K and k = 2.45 × 10-7 s-1 at 601 K?

Accepted Answer

A)  113 kJ/mol 
B)  83 kJ/mol 
C)  410 kJ/mol 
D)  280 kJ/mol 
E)  580 kJ/mol 
A)  113 kJ/mol 
B)  83 kJ/mol 
C)  410 kJ/mol 
D)  280 kJ/mol 
E)  580 kJ/mol

Question 14

For the reaction C6H14(g) → C6H6(g) + 4H2(g), ΔP(H2)/Δt was found to be 2.5 × 10-2 atm/s, where ΔP(H2) is the change in pressure of hydrogen. Determine ΔP(C6H14)/Δt for this reaction at the same time.

Accepted Answer

A)  2.5 × 10-2 atm/s 
B)  -6.3 × 10-3 atm/s 
C)  -2.5 × 10-2 atm/s 
D)  0.10 atm/s 
E)  6.3 × 10-3 atm/s 
A)  2.5 × 10-2 atm/s 
B)  -6.3 × 10-3 atm/s 
C)  -2.5 × 10-2 atm/s 
D)  0.10 atm/s 
E)  6.3 × 10-3 atm/s

Question 15

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

Question 16

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-1 
A)  -0.135 min-1 
B)  0.0279 min-1 
C)  0.089 min-1  
D)  0.135 min-1 
E)  35.8 min-1

Question 17

The following diagram represents the second-order decomposition of A to form X according to the following balanced chemical equation: A → X. Each sphere represents 1.0 mmol of atoms, and the volume of the box is 1.0 L.   What is the half-life of the reaction?

Accepted Answer

A)  15 s 
B)  30 s 
C)  36 s 
D)  45 s 
E)  60 s 
A)  15 s 
B)  30 s 
C)  36 s 
D)  45 s 
E)  60 s

Question 18

A first-order reaction has a rate constant of 3.00 × 10-3 s-1. The time required for the reaction to be 75.0% complete is

Accepted Answer

A)  95.8 s. 
B)  462 s. 
C)  231 s. 
D)  201 s. 
E)  41.7 s. 
A)  95.8 s. 
B)  462 s. 
C)  231 s. 
D)  201 s. 
E)  41.7 s.

Question 19

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 20

Consider the following potential energy profile for the A → B reaction. Assuming that the frequency factor for the reaction is 5.5 × 1010 s-1, what is the rate constant of this first-order reaction at 310 K?

Accepted Answer

A)  2 × 102 s-1 
B)  5 × 105 s-1 
C)  1 × 1019 s-1 
D)  2 × 107 s-1 
A)  2 × 102 s-1 
B)  5 × 105 s-1 
C)  1 × 1019 s-1 
D)  2 × 107 s-1

Exam 14: Chemical Kinetics

For the chemical reaction A → C, a plot of 1/[A]t versus time was found to give a straight line with a positive slope. What is the order of reaction?

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?

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+]. What is the order of the reaction with respect to I-?

The ________ is the name given to the sequence of steps that sum to give the overall reaction.

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

It takes 42.0 min for the concentration of a reactant in a first-order reaction to drop from 0.45 M to 0.32 M at 25°C. How long will it take for the reaction to be 90% complete?

For the reaction 2A + B + 2C → D + E The following initial rate data were collected at constant temperature. What is the correct rate law for this reaction?

What is the rate expression for the production of X, which is a gas, at constant volume?

The activation energy for the following reaction is 60. kJ/mol. Sn2+ + 2Co3+ → Sn4+ + 2Co2+ By what factor will the rate constant increase when the temperature is raised from 10°C to 28°C? (R = 8.314 J/mol• K)

The elementary reaction HBr(g) + Br(g) → H(g) + Br2 (g) is endothermic. Would you expect the rate constant for the back reaction to be smaller or larger than that for the forward reaction? Explain, briefly.

A catalyst increases the rate of the reaction and is recovered completely at the end of the reaction.

A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?

What is the activation energy for a reaction if k = 1.89 × 10-8 s-1 at 540. K and k = 2.45 × 10-7 s-1 at 601 K?

For the reaction C6H14(g) → C6H6(g) + 4H2(g), ΔP(H2)/Δt was found to be 2.5 × 10-2 atm/s, where ΔP(H2) is the change in pressure of hydrogen. Determine ΔP(C6H14)/Δt for this reaction at the same time.

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

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?

The following diagram represents the second-order decomposition of A to form X according to the following balanced chemical equation: A → X. Each sphere represents 1.0 mmol of atoms, and the volume of the box is 1.0 L. What is the half-life of the reaction?

A first-order reaction has a rate constant of 3.00 × 10-3 s-1. The time required for the reaction to be 75.0% complete is

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?

Consider the following potential energy profile for the A → B reaction. Assuming that the frequency factor for the reaction is 5.5 × 1010 s-1, what is the rate constant of this first-order reaction at 310 K?

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For the chemical reaction A → C, a plot of 1/[A]_t versus time was found to give a straight line with a positive slope. What is the order of reaction?

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?

The activation energy for the following reaction is 60. kJ/mol. Sn²⁺ + 2Co³⁺→ Sn⁴⁺ + 2Co²⁺ By what factor will the rate constant increase when the temperature is raised from 10°C to 28°C? (R = 8.314 J/mol• K)

The elementary reaction HBr(g) + Br(g) → H(g) + Br₂ (g) is endothermic. Would you expect the rate constant for the back reaction to be smaller or larger than that for the forward reaction? Explain, briefly.

What is the activation energy for a reaction if k = 1.89 × 10^-8s^-1 at 540. K and k = 2.45 × 10^-7s^-1 at 601 K?

For the reaction C₆H₁₄(g) → C₆H₆(g) + 4H₂(g), ΔP(H₂)/Δt was found to be 2.5 × 10^-2 atm/s, where ΔP(H₂) is the change in pressure of hydrogen. Determine ΔP(C₆H₁₄)/Δt for this reaction at the same time.

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?

A first-order reaction has a rate constant of 3.00 × 10^-3s^-1. The time required for the reaction to be 75.0% complete is

Consider the following potential energy profile for the A → B reaction. Assuming that the frequency factor for the reaction is 5.5 × 10¹⁰ s^-1, what is the rate constant of this first-order reaction at 310 K?