Question 1

For the hypothetical reaction A + 3B → 2C,the rate should be expressed as

Accepted Answer

A)  rate = Δ[A]/Δt.
B)  rate = -Δ[C]/Δt.
C)  rate = -3(Δ[B]/Δt) .
D)  rate = (1/2) (Δ[C]/Δt) .
E)  rate = (1/3) (Δ[B]/Δt) .

Question 2

Nitric oxide gas (NO) reacts with chlorine gas according to the equation 2 (M)          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" class="answers-bank-image d-inline" rel="preload" > The following initial rates of reaction have been measured for the given reagent concentrations. Cl2 (M)  2 (M)          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" class="answers-bank-image d-inline" rel="preload" > 2 (M)          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" class="answers-bank-image d-inline" rel="preload" > 2 (M)          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" class="answers-bank-image d-inline" rel="preload" > 2 (M)          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" class="answers-bank-image d-inline" rel="preload" >

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

Question 3

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)

Question 4

What is the name given to the slowest step in the mechanism of a reaction?

Accepted Answer

A)  Catalytic step
B)  Mechanistic step
C)  Rate-determining step
D)  Step 1
E)  Rate step

Question 5

The reaction A + 2B → products has been found to have the rate law,rate = k[A][B]2.While holding the concentration of A constant,the concentration of B is increased to three times its initial value.By what factor does the rate of reaction increase?

Accepted Answer

A)  3
B)  6
C)  9
D)  27
E)  30

Question 6

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

Question 7

At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 × 10-3 min-1.If the starting concentration of pesticide is 0.0314 M,what concentration will remain after 62.0 min at 25°C?

Accepted Answer

A)  1.14 × 10-1 M
B)  47.4 M
C)  1.25 ×10-2 M
D)  2.11 × 10-2 M
E)  2.68 × 10-2 M

Question 8

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

Accepted Answer

A)  t1/2 = k
B)  t1/2 = 1/k[A]o
C)  t1/2 = 0.693/k[A]o
D)  t1/2 = [A]o/2k
E)  t1/2 = 0.693/k

Question 9

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

Question 10

Consider reactions A,B,and C,which have the potential energy profiles shown.Assuming that the reactions have roughly the same frequency factors,which reaction is the slowest?

Accepted Answer

A)  Reaction A
B)  Reaction B
C)  Reaction C
D)  All of the reactions have the same rate.

Question 11

A reaction intermediate is a species corresponding to a local energy maximum on a reaction energy diagram.

Accepted Answer

A) True 
 B)False

Question 12

The following diagram represents the zeroth-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

Question 13

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

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 14

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

Question 15

A(n)_______________ is the name given to a collision that does result in a reaction.

Accepted Answer

The answer of A(n)_______________ is the name given to a...

Question 16

The following is an Arrhenius plot of a first-order reaction.The rate constant is measured in units of s-1. -1.   Based on this Arrhenius plot,what is the Arrhenius frequency factor (A) of the reaction? (R =8.314 J/K mol)  A) 5.0 s-1 B) 40 s-1 C) 50 s-1 D) 5.0 × 103 s-1 E) 2.4 × 1017 s-1" class="answers-bank-image d-inline" rel="preload" > Based on this Arrhenius plot,what is the Arrhenius frequency factor (A) of the reaction? (R =8.314 J/K mol)

Accepted Answer

A)  5.0 s-1
B)  40 s-1
C)  50 s-1
D)  5.0 × 103 s-1
E)  2.4 × 1017 s-1

Question 17

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

Question 18

The rate constant for the reaction 3A → 4B is 6.00 × 10-3 L • mol-1 • min-1.How long will it take the concentration of A to drop from 0.75 M to 0.25 M?

Accepted Answer

A)  2.2 × 10-3 min
B)  5.5 × 10-3 min
C)  180 min
D)  440 min
E)  5.0 × 102min

Question 19

Sucrose decomposes to fructose and glucose in acid solution.When ln [sucrose] is plotted vs.time,a straight line with slope of -0.208 h-1 results.What is the rate law for the reaction?

Accepted Answer

A)  Rate = (0.208 h-1) [sucrose]2
B)  Rate = (0.208 h-1) [sucrose]
C)  Rate = (0.0433 h) [sucrose]2
D)  Rate = (0.0433 h) [sucrose]
E)  Rate = (0.208 mol L-1 • h-1) [sucrose]0

Question 20

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

Exam 14: Chemical Kinetics

A reaction intermediate is a species corresponding to a local energy maximum on a reaction energy diagram.

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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?

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The rate constant for the reaction 3A → 4B is 6.00 × 10-3 L • mol-1 • min-1.How long will it take the concentration of A to drop from 0.75 M to 0.25 M?

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

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A(n)_______________ is the name given to a collision that does result in a reaction.

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Consider reactions A,B,and C,which have the potential energy profiles shown.Assuming that the reactions have roughly the same frequency factors,which reaction is the slowest?

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The reaction A + 2B → products has been found to have the rate law,rate = k[A][B]2.While holding the concentration of A constant,the concentration of B is increased to three times its initial value.By what factor does the rate of reaction increase?

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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?

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The following diagram represents the zeroth-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?

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At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 × 10-3 min-1.If the starting concentration of pesticide is 0.0314 M,what concentration will remain after 62.0 min at 25°C?

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

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For the hypothetical reaction A + 3B → 2C,the rate should be expressed as

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

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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?

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Sucrose decomposes to fructose and glucose in acid solution.When ln [sucrose] is plotted vs.time,a straight line with slope of -0.208 h-1 results.What is the rate law for the reaction?

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What is the name given to the slowest step in the mechanism of a reaction?

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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?

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Nitric oxide gas (NO) reacts with chlorine gas according to the equation The following initial rates of reaction have been measured for the given reagent concentrations. Cl2 (M)

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The following is an Arrhenius plot of a first-order reaction.The rate constant is measured in units of s-1. Based on this Arrhenius plot,what is the Arrhenius frequency factor (A) of the reaction? (R =8.314 J/K mol)

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

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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?

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The rate constant for the reaction 3A → 4B is 6.00 × 10^-3 L • mol^-1 • min^-1.How long will it take the concentration of A to drop from 0.75 M to 0.25 M?

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Correct Answer
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Correct Answer
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Correct Answer
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The reaction A + 2B → products has been found to have the rate law,rate = k[A][B]².While holding the concentration of A constant,the concentration of B is increased to three times its initial value.By what factor does the rate of reaction increase?

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Correct Answer
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At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 × 10^-3 min-1.If the starting concentration of pesticide is 0.0314 M,what concentration will remain after 62.0 min at 25°C?

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

Correct Answer
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Sucrose decomposes to fructose and glucose in acid solution.When ln [sucrose] is plotted vs.time,a straight line with slope of -0.208 h^-1 results.What is the rate law for the reaction?

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Correct Answer
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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?

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Nitric oxide gas (NO) reacts with chlorine gas according to the equation The following initial rates of reaction have been measured for the given reagent concentrations. Cl₂ (M)

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The following is an Arrhenius plot of a first-order reaction.The rate constant is measured in units of s^-1. Based on this Arrhenius plot,what is the Arrhenius frequency factor (A) of the reaction? (R =8.314 J/K mol)

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Correct Answer
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