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). 
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

For the reaction X + Y → Z, the reaction rate is found to depend only upon the concentration of X. A plot of 1/X versus time gives a straight line.   What is the rate law for this reaction?

Accepted Answer

A)  rate = k [X] 
B)  rate = k [X]2 
C)  rate = k [X][Y] 
D)  rate = k [X]2[Y] 
E)  rate = k [X]2/[Y] 
A)  rate = k [X] 
B)  rate = k [X]2 
C)  rate = k [X][Y] 
D)  rate = k [X]2[Y] 
E)  rate = k [X]2/[Y]

Question 3

What is the half-life for a second-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 
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 4

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

Accepted Answer

A) True 
 B)False

Question 5

The activation energy for the following first-order reaction is 102 kJ/mol. N2O5(g) → 2NO2(g) + (1/2)O2(g)
The value of the rate constant (k) is 1.35 × 10-4 s-1 at 35°C. What is the value of k at 0°C? (R = 8.314 J/mol• K)

Accepted Answer

A)  8.2 × 10-7 s-1 
B)  1.9 × 10-5 s-1 
C)  4.2 × 10-5 s-1 
D)  2.2 × 10-2 s-1 
E)  1.2 × 106s-1 
A)  8.2 × 10-7 s-1 
B)  1.9 × 10-5 s-1 
C)  4.2 × 10-5 s-1 
D)  2.2 × 10-2 s-1 
E)  1.2 × 106s-1

Question 6

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)

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 
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 7

Ammonium cyanate (NH4CNO) reacts to form urea (NH2CONH2). At 65°C the rate constant, k, is 3.60 L • mol-1 • s-1. What is the rate law for this reaction?

Accepted Answer

A)  Rate = (3.60 L • mol-1 • s-1)[NH4CNO] 
B)  Rate = (3.60 L • mol-1 • s-1)[NH4CNO]2 
C)  Rate = (0.28 mol • L-1 • s-1)[NH4CNO] 
D)  Rate = (0.28 mol • L-1 • s-1)[NH4CNO]2 
E)  Rate = (3.60 L • mol-1 • s-1)[NH2CONH2]-1 
A)  Rate = (3.60 L • mol-1 • s-1)[NH4CNO] 
B)  Rate = (3.60 L • mol-1 • s-1)[NH4CNO]2 
C)  Rate = (0.28 mol • L-1 • s-1)[NH4CNO] 
D)  Rate = (0.28 mol • L-1 • s-1)[NH4CNO]2 
E)  Rate = (3.60 L • mol-1 • s-1)[NH2CONH2]-1

Question 8

Consider the reaction 2NOBr(g) → 2NO(g) + Br2(g). The initial rate of the reaction was measured for three different concentrations of NOBr, given below.   Based on the initial rate data above, what is the value of the rate constant?

Accepted Answer

A)  0.0360 L • mol-1 • s-1 
B)  0.800 L • mol-1 • s-1 
C)  1.25 L • mol-1 • s-1 
D)  27.8 L • mol-1 • s-1 
E)  0.0360 s-1 
A)  0.0360 L • mol-1 • s-1 
B)  0.800 L • mol-1 • s-1 
C)  1.25 L • mol-1 • s-1 
D)  27.8 L • mol-1 • s-1 
E)  0.0360 s-1

Question 9

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. t 
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. t

Question 10

A certain first-order reaction A → B is 25% complete in 42 min at 25°C. What is its rate constant?

Accepted Answer

A)  6.8 × 10-3 min-1 
B)  8.3 × 10-3 min-1 
C)  3.3 × 10-2 min-1  
D)  -3.3 × 10-2 min-1 
E)  11 min-1 
A)  6.8 × 10-3 min-1 
B)  8.3 × 10-3 min-1 
C)  3.3 × 10-2 min-1  
D)  -3.3 × 10-2 min-1 
E)  11 min-1

Question 11

What is the integrated rate law for a zeroth-order reaction?

Accepted Answer

A)  rate = k[A]t 
B)    
C)    
D)    
E)    
A)  rate = k[A]t 
B)    
C)    
D)    
E)

Question 12

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...

Question 13

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 14

The reaction A + 2B → Products has the rate law, rate = k[A][B]3. If the concentration of B is doubled while that of A is unchanged, by what factor will the rate of reaction increase?

Accepted Answer

A)  2 
B)  4 
C)  6 
D)  8 
E)  9 
A)  2 
B)  4 
C)  6 
D)  8 
E)  9

Question 15

The rate law for the reaction 3A → C is rate = 4.36 × 10-2 L• mol-1 • h-1[A]2. What is the half-life for the reaction if the initial concentration of A is 0.250 M?

Accepted Answer

A)  0.0109 h 
B)  0.0629 h 
C)  15.9 h 
D)  23.9 h 
E)  91.7 h 
A)  0.0109 h 
B)  0.0629 h 
C)  15.9 h 
D)  23.9 h 
E)  91.7 h

Question 16

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 M 
A)  0.0052 M 
B)  0.024 M 
C)  43 M 
D)  190 M 
E)  0.0000 M

Question 17

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 
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 18

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

Question 19

What statement below best describes the graph representing the integrated first-order rate law?

Accepted Answer

A)  A plot of [A]t vs. t yields a straight line with a negative slope equal to -k. 
B)  A plot of 1/[A]t vs. t yields a straight line with a negative slope equal to k. 
C)  A plot of ln[A]t vs. t yields a straight line with a positive slope equal to -k. 
D)  A plot of ln[A]t vs. t yields a straight line with a negative slope equal to -k. 
E)  A plot of 1/[A]t vs. t yields a straight line with a positive slope equal to k. 
A)  A plot of [A]t vs. t yields a straight line with a negative slope equal to -k. 
B)  A plot of 1/[A]t vs. t yields a straight line with a negative slope equal to k. 
C)  A plot of ln[A]t vs. t yields a straight line with a positive slope equal to -k. 
D)  A plot of ln[A]t vs. t yields a straight line with a negative slope equal to -k. 
E)  A plot of 1/[A]t vs. t yields a straight line with a positive slope equal to k.

Question 20

The ________ is the rate for a specific instant in time.

Accepted Answer

The answer of The ________ is the rate for a...

Exam 14: Chemical Kinetics

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

For the reaction X + Y → Z, the reaction rate is found to depend only upon the concentration of X. A plot of 1/X versus time gives a straight line. What is the rate law for this reaction?

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

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

The activation energy for the following first-order reaction is 102 kJ/mol. N2O5(g) → 2NO2(g) + (1/2)O2(g) The value of the rate constant (k) is 1.35 × 10-4 s-1 at 35°C. What is the value of k at 0°C? (R = 8.314 J/mol• K)

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)

Ammonium cyanate (NH4CNO) reacts to form urea (NH2CONH2). At 65°C the rate constant, k, is 3.60 L • mol-1 • s-1. What is the rate law for this reaction?

Consider the reaction 2NOBr(g) → 2NO(g) + Br2(g). The initial rate of the reaction was measured for three different concentrations of NOBr, given below. Based on the initial rate data above, what is the value of the rate constant?

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?

A certain first-order reaction A → B is 25% complete in 42 min at 25°C. What is its rate constant?

What is the integrated rate law for a zeroth-order reaction?

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

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

The reaction A + 2B → Products has the rate law, rate = k[A][B]3. If the concentration of B is doubled while that of A is unchanged, by what factor will the rate of reaction increase?

The rate law for the reaction 3A → C is rate = 4.36 × 10-2 L• mol-1 • h-1[A]2. What is the half-life for the reaction if the initial concentration of A is 0.250 M?

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?

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?

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?

What statement below best describes the graph representing the integrated first-order rate law?

The ________ is the rate for a specific instant in time.

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The activation energy for the following first-order reaction is 102 kJ/mol. N₂O₅(g) → 2NO₂(g) + (1/2)O₂(g) The value of the rate constant (k) is 1.35 × 10^-4 s^-1at 35°C. What is the value of k at 0°C? (R = 8.314 J/mol• K)

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)

Ammonium cyanate (NH₄CNO) reacts to form urea (NH₂CONH₂). At 65°C the rate constant, k, is 3.60 L • mol^-1• s^-1. What is the rate law for this reaction?

Consider the reaction 2NOBr(g) → 2NO(g) + Br₂(g). The initial rate of the reaction was measured for three different concentrations of NOBr, given below. Based on the initial rate data above, what is the value of the rate constant?

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?

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

The reaction A + 2B → Products has the rate law, rate = k[A][B]³. If the concentration of B is doubled while that of A is unchanged, by what factor will the rate of reaction increase?

The rate law for the reaction 3A → C is rate = 4.36 × 10^-2 L• mol^-1• h^-1[A]². What is the half-life for the reaction if the initial concentration of A is 0.250 M?

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?

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?