Question 1

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled? Rate = k [X][Y]

Accepted Answer

A)  The rate of reaction will increase by a factor of 2. 
B)  The rate of reaction will increase by a factor of 4. 
C)  The rate of reaction will increase by a factor of 5. 
D)  The rate of reaction will decrease by a factor of 2. 
E)  The rate of reaction will remain unchanged. 
A)  The rate of reaction will increase by a factor of 2. 
B)  The rate of reaction will increase by a factor of 4. 
C)  The rate of reaction will increase by a factor of 5. 
D)  The rate of reaction will decrease by a factor of 2. 
E)  The rate of reaction will remain unchanged.

Question 2

The rate constant for a zero-order reaction is 0.54 L mol-1 s-1. What is the half-life of this reaction if the initial concentration is 0.27 mol L-1?

Accepted Answer

A)  2.0 s 
B)  5.0 s 
C)  0.25 s 
D)  6.9 s 
E)  1.3 s 
A)  2.0 s 
B)  5.0 s 
C)  0.25 s 
D)  6.9 s 
E)  1.3 s

Question 3

The rate constant for the first-order decomposition of N2O is 3.40 s-1. What is the half-life of the decomposition?

Accepted Answer

A)  0.491 s 
B)  0.204 s 
C)  0.236 s 
D)  0.424 s 
E)  0.294 s 
A)  0.491 s 
B)  0.204 s 
C)  0.236 s 
D)  0.424 s 
E)  0.294 s

Question 4

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled? Rate = k [X][Y]2

Accepted Answer

A)  The rate of reaction will increase by a factor of 2. 
B)  The rate of reaction will increase by a factor of 4. 
C)  The rate of reaction will increase by a factor of 5. 
D)  The rate of reaction will decrease by a factor of 2. 
E)  The rate of reaction will remain unchanged. 
A)  The rate of reaction will increase by a factor of 2. 
B)  The rate of reaction will increase by a factor of 4. 
C)  The rate of reaction will increase by a factor of 5. 
D)  The rate of reaction will decrease by a factor of 2. 
E)  The rate of reaction will remain unchanged.

Question 5

The first-order reaction, 2N2O(g) → 2N2(g) + O2(g), has a rate constant equal to 0.76 s-1 at 1000 K. How long will it take for the concentration of N2O to decrease to 12% of its initial concentration?

Accepted Answer

A)  0. 62 s 
B)  2.8 s 
C)  6.3 s 
D)  8.4 s 
A)  0. 62 s 
B)  2.8 s 
C)  6.3 s 
D)  8.4 s

Question 6

The half-life for the decay of radium is 1620 years. What is the rate constant for this first-order process?

Accepted Answer

A)  4.28 × 10-4 yr-1 
B)  1.12 × 10-4 yr-1 
C)  2.33 × 10-4 yr-1 
D)  8.91 × 10-4 yr-1 
E)  6.17 × 10-4 yr-1 
A)  4.28 × 10-4 yr-1 
B)  1.12 × 10-4 yr-1 
C)  2.33 × 10-4 yr-1 
D)  8.91 × 10-4 yr-1 
E)  6.17 × 10-4 yr-1

Question 7

Determine the rate law and the value of k for the following reaction using the data provided: 2NO(g) + O2(g) → 2NO2(g) [NO]i (M) [O2]i (M) Initial Rate (M-1 s-1)
0)030 0.0055 8.55 × 10-3
0)030 0.0110 1.71 × 10-2
0)060 0.0055 3.42 × 10-2

Accepted Answer

A)  Rate = 57 M-1 s-1[NO][O2] 
B)  Rate = 3.8 M-1/2 s-1[NO][O2]1/2 
C)  Rate = 3.1 × 105 M-3 s-1[NO]2[O2]2 
D)  Rate = 1.7 × 103 M-2 s-1[NO]2[O2] 
E)  Rate = 9.4 × 103 M-2 s-1[NO][O2]2 
A)  Rate = 57 M-1 s-1[NO][O2] 
B)  Rate = 3.8 M-1/2 s-1[NO][O2]1/2 
C)  Rate = 3.1 × 105 M-3 s-1[NO]2[O2]2 
D)  Rate = 1.7 × 103 M-2 s-1[NO]2[O2] 
E)  Rate = 9.4 × 103 M-2 s-1[NO][O2]2

Question 8

For a particular first-order reaction, it takes 24 minutes for the concentration of the reactant to decrease to 25% of its initial value. What is the value for rate constant (in s-1) for the reaction?

Accepted Answer

A)  2.0 × 10-4 s-1 
B)  9.6 × 10-4 s-1 
C)  1.2 × 10-2 s-1 
D)  5.8 × 10-2 s-1 
A)  2.0 × 10-4 s-1 
B)  9.6 × 10-4 s-1 
C)  1.2 × 10-2 s-1 
D)  5.8 × 10-2 s-1

Question 9

The rate of disappearance of HBr in the gas phase reaction 2HBr(g) →   (g) +   (g)
Is 0.190 mol L-1   at 150 °C. The rate of reaction is ________ mol L-1   .

Accepted Answer

A)  2.63 
B)  0.0361 
C)  0.436 
D)  0.380 
E)  0.0950 
A)  2.63 
B)  0.0361 
C)  0.436 
D)  0.380 
E)  0.0950

Question 10

Calculate the frequency factor, A, for a reaction with a rate constant of 162.3 s-1 and an activation energy, Ea, of 68 kJ mol-1 at 298 K.

Accepted Answer

A)  2.1 × 102 s-1 
B)  2.5 × 103 s-1 
C)  2.6 × 10121 s-1 
D)  1.3 × 1014 s-1 
E)  3.8 × 1011 s-1 
A)  2.1 × 102 s-1 
B)  2.5 × 103 s-1 
C)  2.6 × 10121 s-1 
D)  1.3 × 1014 s-1 
E)  3.8 × 1011 s-1

Question 11

Calculate the temperature if a reaction has a rate constant, k, of 1234 s-1, a frequency factor, A, of 1.34 × 1014 s-1, and an activation energy, Ea, of 79.6 kJ mol-1.

Accepted Answer

A)  298 K 
B)  341 K 
C)  377 K 
D)  418 K 
E)  447 K 
A)  298 K 
B)  341 K 
C)  377 K 
D)  418 K 
E)  447 K

Question 12

For a reaction that follows the general rate law, Rate = k[A][B]2, what will happen to the rate of reaction if the concentration of A is increased by a factor of 5.00?

Accepted Answer

A)  The rate will decrease by a factor of 1/ 25.0. 
B)  The rate will decrease by a factor of 1/ 5.00. 
C)  The rate will increase by a factor of 5.00. 
D)  The rate will increase by a factor of 25.0. 
A)  The rate will decrease by a factor of 1/ 25.0. 
B)  The rate will decrease by a factor of 1/ 5.00. 
C)  The rate will increase by a factor of 5.00. 
D)  The rate will increase by a factor of 25.0.

Question 13

Calculate the frequency factor, A, for a reaction with a rate constant of 7834 s-1 and an activation energy, Ea, of 68.4 kJ mol-1 at 305 K.

Accepted Answer

A)  4.1 × 103 s-1 
B)  8.1 × 103 s-1 
C)  8.1 × 1015 s-1 
D)  4.1 × 1015 s-1 
E)  1.0 × 104 s-1 
A)  4.1 × 103 s-1 
B)  8.1 × 103 s-1 
C)  8.1 × 1015 s-1 
D)  4.1 × 1015 s-1 
E)  1.0 × 104 s-1

Question 14

What is the overall reaction order for the reaction that has the rate law Rate = k[ O2][ NO]2?

Accepted Answer

A)  zero order 
B)  first order 
C)  second order 
D)  third order 
A)  zero order 
B)  first order 
C)  second order 
D)  third order

Question 15

Calculate the activation energy, Ea, for a reaction with a frequency factor, A, of 9.3 × 1010 s-1 and a rate constant of 1.06 × 103 s-1 at 273 K.

Accepted Answer

A)  42 kJ mol-1 
B)  45 kJ mol-1 
C)  36 kJ mol-1 
D)  49 kJ mol-1 
E)  58 kJ mol-1 
A)  42 kJ mol-1 
B)  45 kJ mol-1 
C)  36 kJ mol-1 
D)  49 kJ mol-1 
E)  58 kJ mol-1

Question 16

The combustion of ethylene proceeds by the reaction     (g) +   (g) →   (g) +   O(g) When the rate of disappearance of   is 0.37 mol L-1   , the rate of appearance of   is ________

Accepted Answer

A)  0.12 
B)  1.1 
C)  0.56 
D)  0.74 
E)  0.25 
A)  0.12 
B)  1.1 
C)  0.56 
D)  0.74 
E)  0.25

Question 17

What is one of the conditions that must be met to validate a proposed mechanism?

Accepted Answer

A)  The rate law predicted by the mechanism must be consistent with the experimentally observed rate law. 
B)  The reaction rate law should be defined as the positive of the change in concentration of a reactant divided by the change in time. 
C)  The reaction order with respect to the reactants must be the same as the stoichiometry of the net reaction. 
D)  The rate of the reaction should be independent of the temperature. 
A)  The rate law predicted by the mechanism must be consistent with the experimentally observed rate law. 
B)  The reaction rate law should be defined as the positive of the change in concentration of a reactant divided by the change in time. 
C)  The reaction order with respect to the reactants must be the same as the stoichiometry of the net reaction. 
D)  The rate of the reaction should be independent of the temperature.

Question 18

The isomerization of methylisonitrile to acetonitrile   NC(g) →   CN(g) is first order in   NC. The half-life of the reaction is 8.42 × 10-2 at 575 K. The rate constant when the initial [   NC] is 0.030 mol L-1 is ________   .

Accepted Answer

A)  11.9 
B)  0.178 
C)  396   
D)  0.122 
E)  8.23 
A)  11.9 
B)  0.178 
C)  396   
D)  0.122 
E)  8.23

Question 19

The second-order reaction 2Mn(CO)5 → Mn2(CO)10 has a rate constant equal to 3.0 × 109 L mol-1 s-1 at 25 °C. If the initial concentration of Mn(CO)5 is 2.0 × 10-5 mol L-1, how long will it take for 90.% of the reactant to disappear?

Accepted Answer

A)  6.7 × 10-16 s 
B)  7.4 × 10-15 s 
C)  1.5 × 10-4 s 
D)  6.0 × 103 s 
A)  6.7 × 10-16 s 
B)  7.4 × 10-15 s 
C)  1.5 × 10-4 s 
D)  6.0 × 103 s

Question 20

Which of the following represents the equation for a zero-order half-life?

Accepted Answer

A)  t 1/2 =   
B)  t 1/2 =   
C)  t 1/2 =   
D)  t 1/2 =   
E)  t 1/2 =   
A)  t 1/2 =   
B)  t 1/2 =   
C)  t 1/2 =   
D)  t 1/2 =   
E)  t 1/2 =

Exam 13: Chemical Kinetics

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled? Rate = k [X][Y]

The rate constant for a zero-order reaction is 0.54 L mol-1 s-1. What is the half-life of this reaction if the initial concentration is 0.27 mol L-1?

The rate constant for the first-order decomposition of N2O is 3.40 s-1. What is the half-life of the decomposition?

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled? Rate = k [X][Y]2

The first-order reaction, 2N2O(g) → 2N2(g) + O2(g), has a rate constant equal to 0.76 s-1 at 1000 K. How long will it take for the concentration of N2O to decrease to 12% of its initial concentration?

The half-life for the decay of radium is 1620 years. What is the rate constant for this first-order process?

Determine the rate law and the value of k for the following reaction using the data provided: 2NO(g) + O2(g) → 2NO2(g) [NO]i (M) [O2]i (M) Initial Rate (M-1 s-1) 0)030 0.0055 8.55 × 10-3 0)030 0.0110 1.71 × 10-2 0)060 0.0055 3.42 × 10-2

For a particular first-order reaction, it takes 24 minutes for the concentration of the reactant to decrease to 25% of its initial value. What is the value for rate constant (in s-1) for the reaction?

The rate of disappearance of HBr in the gas phase reaction 2HBr(g) → (g) + (g) Is 0.190 mol L-1 at 150 °C. The rate of reaction is ________ mol L-1 .

Calculate the frequency factor, A, for a reaction with a rate constant of 162.3 s-1 and an activation energy, Ea, of 68 kJ mol-1 at 298 K.

Calculate the temperature if a reaction has a rate constant, k, of 1234 s-1, a frequency factor, A, of 1.34 × 1014 s-1, and an activation energy, Ea, of 79.6 kJ mol-1.

For a reaction that follows the general rate law, Rate = k[A][B]2, what will happen to the rate of reaction if the concentration of A is increased by a factor of 5.00?

Calculate the frequency factor, A, for a reaction with a rate constant of 7834 s-1 and an activation energy, Ea, of 68.4 kJ mol-1 at 305 K.

What is the overall reaction order for the reaction that has the rate law Rate = k[ O2][ NO]2?

Calculate the activation energy, Ea, for a reaction with a frequency factor, A, of 9.3 × 1010 s-1 and a rate constant of 1.06 × 103 s-1 at 273 K.

The combustion of ethylene proceeds by the reaction (g) + (g) → (g) + O(g) When the rate of disappearance of is 0.37 mol L-1 , the rate of appearance of is ________

What is one of the conditions that must be met to validate a proposed mechanism?

The isomerization of methylisonitrile to acetonitrile NC(g) → CN(g) is first order in NC. The half-life of the reaction is 8.42 × 10-2 at 575 K. The rate constant when the initial [ NC] is 0.030 mol L-1 is ________ .

The second-order reaction 2Mn(CO)5 → Mn2(CO)10 has a rate constant equal to 3.0 × 109 L mol-1 s-1 at 25 °C. If the initial concentration of Mn(CO)5 is 2.0 × 10-5 mol L-1, how long will it take for 90.% of the reactant to disappear?

Which of the following represents the equation for a zero-order half-life?

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The rate constant for a zero-order reaction is 0.54 L mol^-1s^-1. What is the half-life of this reaction if the initial concentration is 0.27 mol L^-1?

The rate constant for the first-order decomposition of N₂O is 3.40 s^-1. What is the half-life of the decomposition?

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled? Rate = k [X][Y]²

The first-order reaction, 2N₂O(g) → 2N₂(g) + O₂(g), has a rate constant equal to 0.76 s^-1 at 1000 K. How long will it take for the concentration of N₂O to decrease to 12% of its initial concentration?

Determine the rate law and the value of k for the following reaction using the data provided: 2NO(g) + O₂(g) → 2NO₂(g) [NO]_i(M) [O₂]_i (M) Initial Rate (M^-1s^-1) 0)030 0.0055 8.55 × 10^-3 0)030 0.0110 1.71 × 10^-2 0)060 0.0055 3.42 × 10^-2

For a particular first-order reaction, it takes 24 minutes for the concentration of the reactant to decrease to 25% of its initial value. What is the value for rate constant (in s^-1) for the reaction?

The rate of disappearance of HBr in the gas phase reaction 2HBr(g) → (g) + (g) Is 0.190 mol L^-1 at 150 °C. The rate of reaction is ________ mol L^-1 .

Calculate the frequency factor, A, for a reaction with a rate constant of 162.3 s^-1 and an activation energy, E_a, of 68 kJ mol^-1 at 298 K.

Calculate the temperature if a reaction has a rate constant, k, of 1234 s^-1, a frequency factor, A, of 1.34 × 10¹⁴ s^-1, and an activation energy, E_a, of 79.6 kJ mol^-1.

For a reaction that follows the general rate law, Rate = k[A][B]², what will happen to the rate of reaction if the concentration of A is increased by a factor of 5.00?

Calculate the frequency factor, A, for a reaction with a rate constant of 7834 s^-1 and an activation energy, E_a, of 68.4 kJ mol^-1 at 305 K.

What is the overall reaction order for the reaction that has the rate law Rate = k[ O₂][ NO]²?

Calculate the activation energy, E_a, for a reaction with a frequency factor, A, of 9.3 × 10¹⁰ s^-1 and a rate constant of 1.06 × 10³ s^-1 at 273 K.

The combustion of ethylene proceeds by the reaction (g) + (g) → (g) + O(g) When the rate of disappearance of is 0.37 mol L^-1 , the rate of appearance of is ________

The isomerization of methylisonitrile to acetonitrile NC(g) → CN(g) is first order in NC. The half-life of the reaction is 8.42 × 10^-2 at 575 K. The rate constant when the initial [ NC] is 0.030 mol L^-1 is ________ .

The second-order reaction 2Mn(CO)₅ → Mn₂(CO)₁₀ has a rate constant equal to 3.0 × 10⁹ L mol^-1 s^-1 at 25 °C. If the initial concentration of Mn(CO)₅ is 2.0 × 10^-5 mol L^-1, how long will it take for 90.% of the reactant to disappear?