Question 1

What is the unit of k in the following rate law? Rate = k[X]2

Accepted Answer

A)  mol L-1 s-1 
B)  mol L-1 s 
C)  L mol-1 s-1 
D)  L mol-2 s-1 
E)  M2 s-1 
A)  mol L-1 s-1 
B)  mol L-1 s 
C)  L mol-1 s-1 
D)  L mol-2 s-1 
E)  M2 s-1

Question 2

In aqueous solution, hypobromite ion, BrO-, reacts to produce bromate ion, BrO3-, and bromide ion, Br-, according to the following chemical equation:   A plot of 1/[BrO-] vs. time is linear and the slope is equal to 0.056 L mol-1 s-1. If the initial concentration of BrO- is 0.80 mol L-1, how long will it take one-half of the BrO- ion to react?

Accepted Answer

A)  4.5 × 10-2 s 
B)  7.1 s 
C)  12 s 
D)  22 s 
A)  4.5 × 10-2 s 
B)  7.1 s 
C)  12 s 
D)  22 s

Question 3

If the concentration of a reactant is 6.25%, how many half-lives has it gone through?

Accepted Answer

A)  7 
B)  6 
C)  3 
D)  4 
E)  5 
A)  7 
B)  6 
C)  3 
D)  4 
E)  5

Question 4

The rate constant for a second-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 5

Which of the following is the characteristic of a zero-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 6

What is the overall order of the following reaction, given the rate law? X + 2 Y → 4 Z Rate = k[X][Y]

Accepted Answer

A)  3rd order 
B)  5th order 
C)  2nd order 
D)  1st order 
E)  0th order 
A)  3rd order 
B)  5th order 
C)  2nd order 
D)  1st order 
E)  0th order

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

The first-order decomposition of N2O at 1000 K has a rate constant of 0.76 s-1. If the initial concentration of N2O is 10.9 mol L-1, what is the concentration of N2O after 9.6 s?

Accepted Answer

A)  7.4 × 10-3 mol L-1 
B)  1.0 × 10-3 mol L-1 
C)  1.4 × 10-3 mol L-1 
D)  3.6 × 10-3 mol L-1 
E)  8.7 × 10-3 mol L-1 
A)  7.4 × 10-3 mol L-1 
B)  1.0 × 10-3 mol L-1 
C)  1.4 × 10-3 mol L-1 
D)  3.6 × 10-3 mol L-1 
E)  8.7 × 10-3 mol L-1

Question 9

The decomposition of dinitrogen pentoxide is described by the chemical equation 2N2O5(g) → 4NO2(g) + O2(g).
If the rate of disappearance of N2O5 is equal to 1.60 mol min-1 at a particular moment, what is the rate of appearance of NO2 at that moment?

Accepted Answer

A)  0.800 mol min-1 
B)  1.60 mol min-1 
C)  3.20 mol min-1 
D)  6.40 mol min-1 
A)  0.800 mol min-1 
B)  1.60 mol min-1 
C)  3.20 mol min-1 
D)  6.40 mol min-1

Question 10

A reaction with an activation energy of 34.0 kJ mol-1 has a rate constant of 26.8 s-1 at 354 K. What is the rate constant at 314 K?

Accepted Answer

A)  6.15 s-1 
B)  2.08 s-1 
C)  7.68 s-1 
D)  9.80 s-1 
E)  4.00 s-1 
A)  6.15 s-1 
B)  2.08 s-1 
C)  7.68 s-1 
D)  9.80 s-1 
E)  4.00 s-1

Question 11

Determine the rate law and the value of k for the following reaction using the data provided: S2O82⁻(aq) + 3 I⁻(aq) → 2 SO42⁻(g) + I3⁻(aq) [S2O82⁻]i (M) [I⁻]i (M) Initial Rate (M-1 s-1)
0)30 0.42 4.54
0)44 0.42 6.65
0)44 0.21 3.33

Accepted Answer

A)  Rate = 120 M-2 s-1 [S2O82⁻]2[I⁻] 
B)  Rate = 36 M-1 s-1 [S2O82⁻][I⁻] 
C)  Rate = 86 M-2 s-1 [S2O82⁻][I⁻]2 
D)  Rate = 195 M-3 s-1 [S2O82⁻]2[I⁻]2 
E)  Rate = 23 M-1/2 s-1 [S2O82⁻][I⁻]1/2 
A)  Rate = 120 M-2 s-1 [S2O82⁻]2[I⁻] 
B)  Rate = 36 M-1 s-1 [S2O82⁻][I⁻] 
C)  Rate = 86 M-2 s-1 [S2O82⁻][I⁻]2 
D)  Rate = 195 M-3 s-1 [S2O82⁻]2[I⁻]2 
E)  Rate = 23 M-1/2 s-1 [S2O82⁻][I⁻]1/2

Question 12

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 13

Calculate the temperature if a reaction has a rate constant, k, of 21.3 s-1, a frequency factor, A, of 7.98 × 1013 s-1, and an activation energy, Ea, of 102 kJ mol-1.

Accepted Answer

A)  316 K 
B)  273 K 
C)  381 K 
D)  298 K 
E)  424 K 
A)  316 K 
B)  273 K 
C)  381 K 
D)  298 K 
E)  424 K

Question 14

The reaction that occurs in a Breathalyzer, a device used to determine the alcohol level in a person's bloodstream, is given below. If the rate of appearance of Cr2(SO4)3 is 1.64 mol min-1 at a particular moment, what is the rate of disappearance of C2H6O at that moment? 2K2Cr2O7 + 8H2SO4 + 3C2H6O → 2Cr2(SO4)3 + 2K2SO4 + 11H2O

Accepted Answer

A)  0. 547 mol min-1 
B)  1.09 mol min-1 
C)  2.46 mol min-1 
D)  4.92 mol min-1 
A)  0. 547 mol min-1 
B)  1.09 mol min-1 
C)  2.46 mol min-1 
D)  4.92 mol min-1

Question 15

Match the following.
-t1/2

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 16

The second-order decomposition of HI has a rate constant of 1.80 × 10-3 L mol-1 s-1. How much HI remains after 27.3 s if the initial concentration of HI is 4.78 mol L-1?

Accepted Answer

A)  4.55 mol L-1 
B)  0.258 mol L-1 
C)  3.87 mol L-1 
D)  2.20 mol L-1 
E)  2.39 mol L-1 
A)  4.55 mol L-1 
B)  0.258 mol L-1 
C)  3.87 mol L-1 
D)  2.20 mol L-1 
E)  2.39 mol L-1

Question 17

What is the unit of k in the following rate law? Rate = k[X][Y]1/2

Accepted Answer

A)  mol L-1 s-1 
B)  L mol-1 s-1 
C)  L mol-1/2 s-1 
D)  L1/2 mol-1/2 s-1 
E)  L mol-1 s-1/2 
A)  mol L-1 s-1 
B)  L mol-1 s-1 
C)  L mol-1/2 s-1 
D)  L1/2 mol-1/2 s-1 
E)  L mol-1 s-1/2

Question 18

Given the following rate law, how does the rate of reaction change if the concentration of X 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 19

Identify the rate-determining step.

Accepted Answer

A)  the slowest step 
B)  the faster step 
C)  the fast step 
D)  always the last step 
E)  always the second step 
A)  the slowest step 
B)  the faster step 
C)  the fast step 
D)  always the last step 
E)  always the second step

Question 20

Given the following balanced equation, determine the rate of reaction with respect to [NOCl]. If the rate of NO loss is 1.68 × 10-2 mol L-1 s-1, what is the rate of formation of NOCl? 2NO(g) + Cl2(g) → 2NOCl(g)

Accepted Answer

A)  1.68 × 10-2 mol L-1 s-1 
B)  3.81 × 10-2 mol L-1 s-1 
C)  5.05 × 10-2 mol L-1 s-1 
D)  6.14 × 10-2 mol L-1 s-1 
E)  1.45 × 10-2 mol L-1 s-1 
A)  1.68 × 10-2 mol L-1 s-1 
B)  3.81 × 10-2 mol L-1 s-1 
C)  5.05 × 10-2 mol L-1 s-1 
D)  6.14 × 10-2 mol L-1 s-1 
E)  1.45 × 10-2 mol L-1 s-1

Exam 13: Chemical Kinetics

What is the unit of k in the following rate law? Rate = k[X]2

If the concentration of a reactant is 6.25%, how many half-lives has it gone through?

The rate constant for a second-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?

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

What is the overall order of the following reaction, given the rate law? X + 2 Y → 4 Z Rate = k[X][Y]

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

The first-order decomposition of N2O at 1000 K has a rate constant of 0.76 s-1. If the initial concentration of N2O is 10.9 mol L-1, what is the concentration of N2O after 9.6 s?

The decomposition of dinitrogen pentoxide is described by the chemical equation 2N2O5(g) → 4NO2(g) + O2(g). If the rate of disappearance of N2O5 is equal to 1.60 mol min-1 at a particular moment, what is the rate of appearance of NO2 at that moment?

A reaction with an activation energy of 34.0 kJ mol-1 has a rate constant of 26.8 s-1 at 354 K. What is the rate constant at 314 K?

Determine the rate law and the value of k for the following reaction using the data provided: S2O82⁻(aq) + 3 I⁻(aq) → 2 SO42⁻(g) + I3⁻(aq) [S2O82⁻]i (M) [I⁻]i (M) Initial Rate (M-1 s-1) 0)30 0.42 4.54 0)44 0.42 6.65 0)44 0.21 3.33

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

Calculate the temperature if a reaction has a rate constant, k, of 21.3 s-1, a frequency factor, A, of 7.98 × 1013 s-1, and an activation energy, Ea, of 102 kJ mol-1.

Match the following. -t1/2

The second-order decomposition of HI has a rate constant of 1.80 × 10-3 L mol-1 s-1. How much HI remains after 27.3 s if the initial concentration of HI is 4.78 mol L-1?

What is the unit of k in the following rate law? Rate = k[X][Y]1/2

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

Identify the rate-determining step.

Given the following balanced equation, determine the rate of reaction with respect to [NOCl]. If the rate of NO loss is 1.68 × 10-2 mol L-1 s-1, what is the rate of formation of NOCl? 2NO(g) + Cl2(g) → 2NOCl(g)

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Filters

What is the unit of k in the following rate law? Rate = k[X]²

The rate constant for a second-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 first-order decomposition of N₂O at 1000 K has a rate constant of 0.76 s^-1. If the initial concentration of N₂O is 10.9 mol L^-1, what is the concentration of N₂O after 9.6 s?

The decomposition of dinitrogen pentoxide is described by the chemical equation 2N₂O₅(g) → 4NO₂(g) + O₂(g). If the rate of disappearance of N₂O₅ is equal to 1.60 mol min^-1 at a particular moment, what is the rate of appearance of NO₂ at that moment?

A reaction with an activation energy of 34.0 kJ mol^-1 has a rate constant of 26.8 s^-1 at 354 K. What is the rate constant at 314 K?

Determine the rate law and the value of k for the following reaction using the data provided: S₂O₈²⁻(aq) + 3 I⁻(aq) → 2 SO₄²⁻(g) + I₃⁻(aq) [S₂O₈²⁻]_i(M) [I⁻]_i (M) Initial Rate (M^-1s^-1) 0)30 0.42 4.54 0)44 0.42 6.65 0)44 0.21 3.33

Calculate the temperature if a reaction has a rate constant, k, of 21.3 s^-1, a frequency factor, A, of 7.98 × 10¹³ s^-1, and an activation energy, E_a, of 102 kJ mol^-1.

Match the following. -t_1/2

The second-order decomposition of HI has a rate constant of 1.80 × 10^-3 L mol^-1s^-1. How much HI remains after 27.3 s if the initial concentration of HI is 4.78 mol L^-1?

What is the unit of k in the following rate law? Rate = k[X][Y]^1/2

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

Given the following balanced equation, determine the rate of reaction with respect to [NOCl]. If the rate of NO loss is 1.68 × 10^-2 mol L^-1 s^-1, what is the rate of formation of NOCl? 2NO(g) + Cl₂(g) → 2NOCl(g)