Question 1

What happens to the concentration of reactants and products during a chemical reaction?

Accepted Answer

The concentration of reactants

Question 2

Match the following.
-A

Accepted Answer

A) reaction order 
B) frequency factor 
C) activation energy 
D) rate constant 
E) half-life 
A) reaction order 
B) frequency factor 
C) activation energy 
D) rate constant 
E) half-life

Question 3

How many half-lives are required for the concentration of reactant to decrease to 12.5% of its original value?

Accepted Answer

A)  3 
B)  1 
C)  1.75 
D)  2.75 
E)  2 
A)  3 
B)  1 
C)  1.75 
D)  2.75 
E)  2

Question 4

The first-order decomposition of N2O5 at 328 K has a rate constant of 1.70 × 10-3 s-1. If the initial concentration of N2O5 is 2.88 mol L-1, what is the concentration of N2O5 after 12.5 minutes?

Accepted Answer

A)  0.124 mol L-1 
B)  0.805 mol L-1 
C)  2.82 mol L-1 
D)  0.355 mol L-1 
E)  0.174 mol L-1 
A)  0.124 mol L-1 
B)  0.805 mol L-1 
C)  2.82 mol L-1 
D)  0.355 mol L-1 
E)  0.174 mol L-1

Question 5

For a reaction that follows the general rate law Rate = k[A]-1 [B]2, what will happen to the rate of reaction if the concentration of A and B are increased by a factor of 6?

Accepted Answer

A)  The rate will decrease by a factor of 1/36.00. 
B)  The rate will decrease by a factor of 1/6.00. 
C)  The rate will increase by a factor of 36.00. 
D)  The rate will increase by a factor of 6.00. 
A)  The rate will decrease by a factor of 1/36.00. 
B)  The rate will decrease by a factor of 1/6.00. 
C)  The rate will increase by a factor of 36.00. 
D)  The rate will increase by a factor of 6.00.

Question 6

Carbon-14, which is present in all living tissue, radioactively decays via a first-order process. A one-gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per minute. If the half-life for carbon-14 is 5720 years, how old is a wood sample that gives a rate for carbon-14 decay of 11.9 counts per minute?

Accepted Answer

A)  5.3 × 102 yr 
B)  7.6 × 102 yr 
C)  1.1 × 103 yr 
D)  9.4 × 103 yr 
A)  5.3 × 102 yr 
B)  7.6 × 102 yr 
C)  1.1 × 103 yr 
D)  9.4 × 103 yr

Question 7

Without performing complex calculations, determine the order of a reaction that has the following initial rates for the specified starting concentration:

Accepted Answer

A)  zero order 
B)  first order 
C)  second order 
D)  third order 
E)  impossible to determine 
A)  zero order 
B)  first order 
C)  second order 
D)  third order 
E)  impossible to determine

Question 8

Given the following balanced equation, determine the rate of reaction with respect to [O2]. 2O3(g) → 3O2(g)

Accepted Answer

A)  Rate = -   
B)  Rate = -     
C)  Rate = +     
D)  Rate = +   
E)  It is not possible to determine the answer without more information. 
A)  Rate = -   
B)  Rate = -     
C)  Rate = +     
D)  Rate = +   
E)  It is not possible to determine the answer without more information.

Question 9

A reaction with an activation energy of 65.4 kJ mol-1 has a rate constant of 1.15 s-1 at 354 K. At what temperature will the rate constant be double?

Accepted Answer

A)  365 K 
B)  708 K 
C)  181 K 
D)  340 K 
E)  378 K 
A)  365 K 
B)  708 K 
C)  181 K 
D)  340 K 
E)  378 K

Question 10

The isomerization reaction, CH3NC → CH3CN, is first order and the rate constant is equal to 0.46 s-1 at 600 K. What is the concentration of CH3NC after 0.20 minutes if the initial concentration is 0. 30 mol L-1?

Accepted Answer

A)  1.2 × 10-3 mol L-1 
B)  2.7 × 10-3 mol L-1 
C)  1.2 × 10-1 mol L-1 
D)  2.7 × 10-1 mol L-1 
A)  1.2 × 10-3 mol L-1 
B)  2.7 × 10-3 mol L-1 
C)  1.2 × 10-1 mol L-1 
D)  2.7 × 10-1 mol L-1

Question 11

What is the unit of k in the following rate law? Rate = k[X][Y]

Accepted Answer

A)  mol L-1 s-1 
B)  mol L-1 s 
C)  L mol-1 s-1 
D)    
E)    
A)  mol L-1 s-1 
B)  mol L-1 s 
C)  L mol-1 s-1 
D)    
E)

Question 12

Which of the following statements is TRUE?

Accepted Answer

A)  The rate constant is constant only when the temperature remains constant. 
B)  The rate constant does not depend on the temperature. 
C)  An increase in temperature will decrease the rate constant. 
D)  A decrease in temperature will increase the rate constant. 
E)  The rate constant is always equal to one at room temperature. 
A)  The rate constant is constant only when the temperature remains constant. 
B)  The rate constant does not depend on the temperature. 
C)  An increase in temperature will decrease the rate constant. 
D)  A decrease in temperature will increase the rate constant. 
E)  The rate constant is always equal to one at room temperature.

Question 13

A reaction is found to have an activation energy of 38.0 kJ mol-1. If the rate constant for this reaction is 1.60 × 102 L mol-1 s-1 at 249 K, what is the rate constant at 436 K?

Accepted Answer

A)  2.38 × 105 L mol-1 s-1 
B)  1.26 × 103 L mol-1 s-1 
C)  7.94 × 104 L mol-1 s-1 
D)  4.20 × 105 L mol-1 s-1 
E)  3.80 × 104 L mol-1 s-1 
A)  2.38 × 105 L mol-1 s-1 
B)  1.26 × 103 L mol-1 s-1 
C)  7.94 × 104 L mol-1 s-1 
D)  4.20 × 105 L mol-1 s-1 
E)  3.80 × 104 L mol-1 s-1

Question 14

decomposes in the gas phase by the reaction     (g) →   (g) +   (g) The reaction is first order in     and the rate constant is 3.0 ×     at 600 K. A vessel is charged with 6.4 atm of   at 600 K. The partial pressure of     at   is ________ atm.

Accepted Answer

A)  0.41 
B)  0.064 
C)  3.8 
D)  0.29 
E)  2.6 
A)  0.41 
B)  0.064 
C)  3.8 
D)  0.29 
E)  2.6

Question 15

Given the following balanced equation, determine the rate of reaction with respect to [H2]. N2(g) + 3H2(g) → 2NH3(g)

Accepted Answer

A)  Rate = +   
B)  Rate = -     
C)  Rate = +     
D)  Rate = -     
E)  It is not possible to determine the answer without more information. 
A)  Rate = +   
B)  Rate = -     
C)  Rate = +     
D)  Rate = -     
E)  It is not possible to determine the answer without more information.

Question 16

The second-order decomposition of NO2 has a rate constant of 0.255 L mol-1 s-1. How much NO2 decomposes in 4.00 s if the initial concentration of NO2 (1.00 L volume) is 1.33 mol L-1?

Accepted Answer

A)  1.8 mol 
B)  0.85 mol 
C)  0.48 mol 
D)  0.77 mol 
E)  0.56 mol 
A)  1.8 mol 
B)  0.85 mol 
C)  0.48 mol 
D)  0.77 mol 
E)  0.56 mol

Question 17

The elementary reaction   (g) → 2NO(g) +   (g) is second order in   and the rate constant at 515 K is 1.64 × 10-2 
      . The reaction half-life at this temperature when   = 0.45 mol L-1 is ________ s.

Accepted Answer

A)  13 
B)  2.4 × 10-2 
C)  42 
D)  7.4 × 10-3 
E)  1.4 × 102 
A)  13 
B)  2.4 × 10-2 
C)  42 
D)  7.4 × 10-3 
E)  1.4 × 102

Question 18

What is the unit of k in a zero-order reaction?

Accepted Answer

A)  mol L-1 s-1 
B)  mol L-1 s 
C)  L mol-1 s-1 
D)  M2 s-1 
E)  s-1 
A)  mol L-1 s-1 
B)  mol L-1 s 
C)  L mol-1 s-1 
D)  M2 s-1 
E)  s-1

Question 19

Which of the following is the characteristic of a first-order reaction having only one reactant?

Accepted Answer

A)  The rate of the reaction is not proportional to the concentration of the reactant. 
B)  The rate of the reaction is proportional to the square of the concentration of the reactant. 
C)  The rate of the reaction is proportional to the square root of the concentration of the reactant. 
D)  The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant. 
E)  The rate of the reaction is directly proportional to the concentration of the reactant. 
A)  The rate of the reaction is not proportional to the concentration of the reactant. 
B)  The rate of the reaction is proportional to the square of the concentration of the reactant. 
C)  The rate of the reaction is proportional to the square root of the concentration of the reactant. 
D)  The rate of the reaction is proportional to the natural logarithm of the concentration of the reactant. 
E)  The rate of the reaction is directly proportional to the concentration of the reactant.

Question 20

The isomerization of methylisonitrile to acetonitrile   NC(g) →   CN(g) is first order in   NC. The rate constant for the reaction is 5.26 × 10-3   at 531 K. The   of the reaction when the initial [   NC] is 0.030 mol L-1 is ________ s.

Accepted Answer

A)  4.38 × 102 
B)  2.85 
C)  6.34 × 103 
D)  7.59 × 10-3 
E)  1.32 × 102 
A)  4.38 × 102 
B)  2.85 
C)  6.34 × 103 
D)  7.59 × 10-3 
E)  1.32 × 102

Exam 13: Chemical Kinetics

What happens to the concentration of reactants and products during a chemical reaction?

Match the following. -A

How many half-lives are required for the concentration of reactant to decrease to 12.5% of its original value?

The first-order decomposition of N2O5 at 328 K has a rate constant of 1.70 × 10-3 s-1. If the initial concentration of N2O5 is 2.88 mol L-1, what is the concentration of N2O5 after 12.5 minutes?

For a reaction that follows the general rate law Rate = k[A]-1 [B]2, what will happen to the rate of reaction if the concentration of A and B are increased by a factor of 6?

Without performing complex calculations, determine the order of a reaction that has the following initial rates for the specified starting concentration:

Given the following balanced equation, determine the rate of reaction with respect to [O2]. 2O3(g) → 3O2(g)

A reaction with an activation energy of 65.4 kJ mol-1 has a rate constant of 1.15 s-1 at 354 K. At what temperature will the rate constant be double?

The isomerization reaction, CH3NC → CH3CN, is first order and the rate constant is equal to 0.46 s-1 at 600 K. What is the concentration of CH3NC after 0.20 minutes if the initial concentration is 0. 30 mol L-1?

What is the unit of k in the following rate law? Rate = k[X][Y]

Which of the following statements is TRUE?

A reaction is found to have an activation energy of 38.0 kJ mol-1. If the rate constant for this reaction is 1.60 × 102 L mol-1 s-1 at 249 K, what is the rate constant at 436 K?

decomposes in the gas phase by the reaction (g) → (g) + (g) The reaction is first order in and the rate constant is 3.0 × at 600 K. A vessel is charged with 6.4 atm of at 600 K. The partial pressure of at is ________ atm.

Given the following balanced equation, determine the rate of reaction with respect to [H2]. N2(g) + 3H2(g) → 2NH3(g)

The second-order decomposition of NO2 has a rate constant of 0.255 L mol-1 s-1. How much NO2 decomposes in 4.00 s if the initial concentration of NO2 (1.00 L volume) is 1.33 mol L-1?

The elementary reaction (g) → 2NO(g) + (g) is second order in and the rate constant at 515 K is 1.64 × 10-2 . The reaction half-life at this temperature when = 0.45 mol L-1 is ________ s.

What is the unit of k in a zero-order reaction?

Which of the following is the characteristic of a first-order reaction having only one reactant?

The isomerization of methylisonitrile to acetonitrile NC(g) → CN(g) is first order in NC. The rate constant for the reaction is 5.26 × 10-3 at 531 K. The of the reaction when the initial [ NC] is 0.030 mol L-1 is ________ s.

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Filters

The first-order decomposition of N₂O₅ at 328 K has a rate constant of 1.70 × 10^-3 s^-1. If the initial concentration of N₂O₅ is 2.88 mol L^-1, what is the concentration of N₂O₅ after 12.5 minutes?

For a reaction that follows the general rate law Rate = k[A]^-1[B]², what will happen to the rate of reaction if the concentration of A and B are increased by a factor of 6?

Given the following balanced equation, determine the rate of reaction with respect to [O₂]. 2O₃(g) → 3O₂(g)

A reaction with an activation energy of 65.4 kJ mol^-1 has a rate constant of 1.15 s^-1 at 354 K. At what temperature will the rate constant be double?

The isomerization reaction, CH₃NC → CH₃CN, is first order and the rate constant is equal to 0.46 s^-1 at 600 K. What is the concentration of CH₃NC after 0.20 minutes if the initial concentration is 0. 30 mol L^-1?

A reaction is found to have an activation energy of 38.0 kJ mol^-1. If the rate constant for this reaction is 1.60 × 10² L mol^-1s^-1 at 249 K, what is the rate constant at 436 K?

Given the following balanced equation, determine the rate of reaction with respect to [H₂]. N₂(g) + 3H₂(g) → 2NH₃(g)

The second-order decomposition of NO₂ has a rate constant of 0.255 L mol^-1s^-1. How much NO₂ decomposes in 4.00 s if the initial concentration of NO₂ (1.00 L volume) is 1.33 mol L^-1?

The elementary reaction (g) → 2NO(g) + (g) is second order in and the rate constant at 515 K is 1.64 × 10^-2 . The reaction half-life at this temperature when = 0.45 mol L^-1 is ________ s.

The isomerization of methylisonitrile to acetonitrile NC(g) → CN(g) is first order in NC. The rate constant for the reaction is 5.26 × 10^-3 at 531 K. The of the reaction when the initial [ NC] is 0.030 mol L^-1 is ________ s.