Master Chemical Reaction Rates: Kinetics Learning Quizzes

Question 1

The rate of a reaction can be increased by adding a catalyst. Which of the following statements about catalysts is true?

Accepted Answer

Catalysts lower the activation energy of the reaction.

Answer

Catalysts are consumed during the reaction.

Answer

Catalysts increase the equilibrium constant of the reaction.

Answer

Catalysts change the products of the reaction.

Question 2

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

Accepted Answer

The rate law is first-order.

Answer

The activation energy is typically high.

Answer

The reaction proceeds via an intermediate.

Answer

The rate-determining step involves two molecules colliding.

Question 3

In a reaction between two reactants, A and B, the rate law is found to be: Rate = k[A][B]^2. What is the order of the reaction with respect to reactant B?

Accepted Answer

2

Answer

0

Answer

1

Answer

3

Question 4

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

Accepted Answer

Third order

Answer

First order

Answer

Second order

Answer

Zero order

Question 5

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

Accepted Answer

M^-1s^-1

Answer

M/s

Answer

s^-1

Answer

M

Question 6

A catalyst:

Accepted Answer

Provides an alternative reaction pathway with a lower activation energy

Answer

Increases the activation energy of a reaction

Answer

Consumes reactants

Answer

Decreases the rate of a reaction

Question 7

Which of the following experimental techniques is used to study very fast reactions?

Accepted Answer

Stopped-flow spectroscopy

Answer

Nuclear magnetic resonance (NMR)

Answer

Mass spectrometry

Answer

High-performance liquid chromatography (HPLC)

Question 8

The Arrhenius equation is expressed as:

Accepted Answer

ln(k) = -Ea/RT + ln(A)

Answer

k = Ae^(-Ea/RT)

Answer

k = RT/Ea

Answer

k = Ae^(-RT/Ea)

Question 9

Which factor has no significant effect on the rate of a chemical reaction?

Accepted Answer

Color of the reaction mixture

Answer

Temperature

Answer

Concentration of reactants

Answer

Surface area of reactants

Question 10

For a reaction with rate law rate = k[A][B], what is the reaction order with respect to A?

Accepted Answer

1

Answer

0

Answer

2

Answer

Cannot be determined

Question 11

Which is not a recognized type of catalysis?

Accepted Answer

Radioactive

Answer

Homogeneous

Answer

Heterogeneous

Answer

Autocatalysis

Question 12

Activation energy is the minimum energy required for reactants to react. Which statement about activation energy is correct?

Accepted Answer

A catalyst can lower activation energy.

Answer

Activation energy is identical for all reactions.

Answer

Activation energy equals the enthalpy change of the reaction.

Answer

Activation energy measures reaction speed.

Question 13

A first-order reaction has a half-life of 10 minutes. Calculate its rate constant.

Accepted Answer

0.0693 min^-1

Answer

0.1000 min^-1

Answer

0.1500 min^-1

Answer

0.2000 min^-1

Question 14

A rate law for a reaction is a mathematical expression that relates the:

Accepted Answer

Rate of reaction to the concentrations of reactants

Answer

Rate of reaction to the activation energy

Answer

Activation energy to the temperature

Answer

Temperature to the concentration of reactants

Question 15

A catalyst is a substance that:

Accepted Answer

Decreases the activation energy of a reaction

Answer

Increases the activation energy of a reaction

Answer

Changes the products of a reaction

Answer

Slows down the rate of a reaction

Question 16

The half-life of a reaction is the time it takes for:

Accepted Answer

The concentration of reactants to decrease by half

Answer

The concentration of products to increase by half

Answer

The rate of reaction to decrease by half

Answer

The temperature to increase by half

Question 17

The order of a reaction is determined by:

Accepted Answer

The rate law of the reaction

Answer

The stoichiometry of the reaction

Answer

The activation energy of the reaction

Answer

The temperature of the reaction

Question 18

Le Chatelier's principle can be used to predict the effect of changes in conditions on:

Accepted Answer

Equilibrium concentrations

Answer

Reaction rates

Answer

Activation energies

Answer

Half-lives

Question 19

Activation energy is defined as the:

Accepted Answer

Minimum energy required for a reaction to proceed

Answer

Difference in energy between reactants and products

Answer

Maximum energy released during a reaction

Answer

Energy required to break reactant bonds

Question 20

The rate law for a first-order reaction is:

Accepted Answer

Rate = k[A]

Answer

Rate = k[A][B]

Answer

Rate = k[A]^2

Answer

Rate = k[A]^3

Question 21

The rate-limiting step of a reaction is the:

Accepted Answer

Slowest step in the reaction mechanism

Answer

First step in the reaction mechanism

Answer

Last step in the reaction mechanism

Question 22

A suitable technique for monitoring reaction kinetics is:

Accepted Answer

Spectrophotometry

Answer

Gas chromatography

Answer

NMR spectroscopy

Answer

X-ray crystallography

Question 23

In the following reaction mechanism, A + B -> C -> D, which species is an intermediate?

Accepted Answer

C

Answer

B

Answer

A