Chemical Kinetics: Master Reaction Rates and Mechanisms

Question 1

The reaction rate is defined as the change in concentration of a reactant or product per unit time. Which of the following is the unit of the reaction rate?

Accepted Answer

mol/L.s

Answer

mol/L

Answer

mol/L²s

Answer

mol/m³

Question 2

The rate law of a reaction expresses the relationship between the reaction rate and the concentrations of reactants. Which of the following is the general form of a rate law?

Accepted Answer

rate = k[A]^m[B]^n

Answer

rate = [A]^m[B]^n

Answer

rate = k[A]/[B]^m[C]^n

Answer

rate = k[A]^m[B]^n/T

Question 3

Catalysts enhance reaction rates without being consumed. Which characteristic is NOT associated with a catalyst?

Accepted Answer

Reacts with products to form new reactants

Answer

Lowers activation energy

Answer

Provides an alternative reaction pathway

Answer

Remains unchanged in quantity at the end of the reaction

Question 4

Which of the following factors has no effect on the rate of a chemical reaction?

Accepted Answer

Volume of the reaction vessel

Answer

Concentration of reactants

Answer

Temperature

Answer

Surface area of reactants

Question 5

The rate law for a reaction is: Rate = k[A][B]^2. What is the order of the reaction with respect to [B]?

Accepted Answer

2

Answer

0

Answer

1

Answer

Cannot be determined from the given information

Question 6

Activation energy is:

Accepted Answer

The minimum amount of energy that must be supplied to the reactants in order for the reaction to occur

Answer

The difference in energy between the reactants and the transition state

Answer

The change in energy when the reaction goes to completion

Answer

The rate at which the reaction occurs

Question 7

Which of the following is NOT a method for determining the rate law of a reaction?

Accepted Answer

Numerical simulation

Answer

Method of initial rates

Answer

Differential rate method

Answer

Integration rate method

Question 8

The half-life of a first-order reaction is 10 minutes. What is the rate constant for the reaction?

Accepted Answer

0.01 min^-1

Answer

0.02 min^-1

Answer

0.03 min^-1

Answer

0.04 min^-1

Question 9

Which of the following statements about catalysts is NOT true?

Accepted Answer

Catalysts are consumed during the reaction

Answer

Catalysts increase the rate of reaction

Answer

Catalysts provide an alternative reaction pathway

Answer

Catalysts lower the activation energy of the reaction

Question 10

Which of the following is the rate law for a second-order reaction in terms of the concentration of a single reactant, A?

Accepted Answer

rate = k[A]^2

Answer

rate = k[A]

Answer

rate = k[A][B]

Answer

rate = k[A]^3

Question 11

What is the relationship between temperature and the rate of a chemical reaction?

Accepted Answer

Rate increases with increasing temperature

Answer

Rate decreases with increasing temperature

Answer

Rate is unaffected by temperature

Answer

Rate first increases and then decreases with increasing temperature

Question 12

Which of the following is a characteristic of a catalytic reaction?

Accepted Answer

The catalyst decreases the activation energy of the reaction

Answer

The catalyst is consumed in the reaction

Answer

The catalyst increases the equilibrium constant of the reaction

Answer

The catalyst is a product in the reaction

Question 13

Which of the following graphical methods is used to determine the order of a reaction with respect to a single reactant?

Accepted Answer

Integrated rate law plot

Answer

Arrhenius plot

Answer

Half-life plot

Answer

van't Hoff plot

Question 14

On a reaction profile, which point represents the transition state? Explain the significance of the transition state in determining the reaction rate.

Accepted Answer

The highest energy point on the profile

Answer

The lowest energy point on the profile

Answer

The initial energy point on the profile

Question 15

Which of the following statements about catalysts is correct?

Accepted Answer

Catalysts participate in a reaction but are regenerated at the end

Answer

Catalysts decrease the rate of a reaction

Answer

Catalysts are consumed during a reaction

Question 16

Which of the following actions will increase the rate of a reaction?

Accepted Answer

Increasing temperature, increasing reactant concentration, and adding a catalyst

Answer

Decreasing temperature and decreasing reactant concentration

Answer

Adding an inhibitor

Question 17

What are the units of the rate constant for a second-order reaction?

Accepted Answer

M^-1 s^-1

Answer

M

Answer

M s^-1

Answer

s

Question 18

Which of the following is an example of a chemical kinetics experiment?

Accepted Answer

Monitoring the change in reactant concentration over time

Answer

Measuring the electrical conductivity of a solution

Answer

Determining the molecular structure of a compound

Question 19

According to the Arrhenius equation, the rate constant of a reaction

Accepted Answer

Increases exponentially with increasing temperature

Answer

Is directly proportional to temperature

Answer

Decreases exponentially with increasing temperature

Question 20

What is the integrated rate law for a second-order reaction, where [A] represents the concentration of the reactant at time t, k is the rate constant, and C is the integration constant?

Accepted Answer

1/[A] = kt + C

Answer

[A] = -kt + C

Answer

1/ln[A] = kt + C

Answer

ln[A] = -kt + C

Question 21

Which of the following reactions is an example of a heterogeneous reaction?

Accepted Answer

The reaction between solid zinc and hydrochloric acid solution.

Answer

The precipitation reaction of silver chloride from solutions of silver nitrate and sodium chloride.

Answer

The combustion of methane gas in air.

Answer

The neutralization reaction of an acid and a base in solution.

Question 22

What does the rate constant (k) of a reaction represent?

Accepted Answer

The proportionality constant that relates the rate of a reaction to the concentrations of reactants.

Answer

The overall order of the reaction.

Answer

The time it takes for the reaction to reach completion.

Answer

The energy required for the reaction to occur.