Chemical Kinetics: Interactive Learning Quizzes for University Students

Question 1

Which of the following statements best describes the Arrhenius equation?

Accepted Answer

The Arrhenius equation links a reaction's rate constant to its temperature and activation energy.

Answer

The Arrhenius equation predicts a reaction's rate at a specific temperature.

Answer

The Arrhenius equation applies only to gas-phase reactions.

Question 2

Which statement about the Arrhenius equation is incorrect?

Accepted Answer

It is a linear equation.

Answer

It relates the rate constant to activation energy and temperature.

Answer

It is expressed in exponential form.

Answer

It can be used to predict reaction rates in different conditions.

Question 3

A catalyst is a substance that increases the rate of a chemical reaction without being consumed. Which of the following mechanisms is used by a catalyst to increase the reaction rate?

Accepted Answer

Lowering the activation energy of the reaction.

Answer

Increasing the concentration of the reactants.

Answer

Providing an alternative pathway for the reaction.

Answer

Altering the equilibrium constant of the reaction.

Question 4

Half-life is the time it takes for half of a substance to decay. Which of the following statements about half-life is true?

Accepted Answer

It is constant for a given substance under constant conditions.

Answer

It is affected by the initial concentration of the substance.

Answer

It is the same for all radioactive decay processes.

Answer

It can be increased by a catalyst.

Question 5

Which of the following statements about activation energy is accurate?

Accepted Answer

Both (A) and (B) are correct.

Answer

It represents the minimum energy needed for a reaction to initiate.

Answer

It is always a positive value.

Answer

Catalysts increase the activation energy of a reaction.

Question 6

What is the function of a catalyst in a chemical reaction?

Accepted Answer

To decrease the activation energy of the reaction

Answer

To increase the activation energy of the reaction

Answer

To change the reaction mechanism

Answer

To consume reactants

Question 7

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

Accepted Answer

Second

Answer

First

Answer

Third

Answer

Zero

Question 8

What is the rate-determining step in a reaction mechanism?

Accepted Answer

The slowest step

Answer

The fastest step

Answer

The step with the highest activation energy

Answer

The step with the lowest activation energy

Question 9

The activation energy of a reaction is defined as:

Accepted Answer

The minimum energy that reactants must possess to undergo a reaction

Answer

The energy difference between the reactants and the products

Answer

The energy released during a reaction

Answer

The rate constant of the reaction

Question 10

A characteristic of a first-order reaction is that:

Accepted Answer

The rate is proportional to the concentration of only one reactant

Answer

The rate constant is independent of reactant concentration

Answer

The rate doubles when the reactant concentration doubles

Answer

The half-life is inversely proportional to the reactant concentration

Question 11

Chemical kinetics is primarily concerned with:

Accepted Answer

The rates of chemical reactions

Answer

The mechanisms of chemical reactions

Answer

The equilibrium of chemical reactions

Answer

The thermodynamics of chemical reactions

Question 12

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

Accepted Answer

2

Answer

0

Answer

1

Answer

Cannot be determined from the given information

Question 13

The activation energy of a reaction is the:

Accepted Answer

Minimum amount of energy required for a reaction to occur

Answer

Energy difference between the reactants and the products

Answer

Energy released in a reaction

Answer

Energy required to break bonds in the reactants

Question 14

The half-life of a radioactive isotope is 10 years. What fraction of the isotope remains after 30 years?

Accepted Answer

0.125

Answer

0.250

Answer

0.375

Answer

0.500

Question 15

The activation energy of a reaction is:

Accepted Answer

The minimum energy required for a reaction to occur

Answer

The difference in energy between the reactants and products

Answer

The rate at which a reaction proceeds

Answer

The equilibrium constant of the reaction

Question 16

A catalyst:

Accepted Answer

Increases the rate of a reaction without being consumed

Answer

Decreases the rate of a reaction without being consumed

Answer

Is a reactant that is consumed in the reaction

Answer

Does not affect the rate of a reaction

Question 17

The half-life of a reaction is:

Accepted Answer

The time it takes for the concentration of the reactants to decrease by half

Answer

The time it takes for the concentration of the products to increase by half

Answer

The time it takes for the reaction to reach equilibrium

Answer

The rate constant of the reaction

Question 18

The rate constant of a reaction:

Accepted Answer

Is a constant that depends on the temperature and the nature of the reactants

Answer

Is a constant that is independent of the temperature and the nature of the reactants

Answer

Is a function of the concentration of the reactants

Answer

Is a function of the activation energy of the reaction

Question 19

The rate law for a reaction is: 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 20

What is the unit of the rate constant for a first-order reaction?

Accepted Answer

s⁻¹

Answer

M/s

Answer

M/s²

Answer

s

Question 21

Activation energy is the minimum amount of energy that must be supplied to reactant molecules in order for them to:

Accepted Answer

Form a transition state

Answer

Collide with each other

Answer

React with each other

Answer

Break their bonds

Question 22

Which of the following is a catalyst?

Accepted Answer

A substance that speeds up a reaction without being consumed

Answer

A substance that slows down a reaction without being consumed

Answer

A substance that is consumed in a reaction and produces more reactants

Answer

A substance that is consumed in a reaction and produces more products

Question 23

Which of the given equations represents a rate law?

Accepted Answer

Rate = k[A][B]^2

Answer

A + B → C

Answer

Ea = -RTln(k)

Answer

T = 1/k

Question 24

What is represented by the Arrhenius equation?

Accepted Answer

The relationship between the rate constant of a reaction and temperature

Answer

The relationship between the activation energy of a reaction and temperature

Answer

The relationship between the half-life of a reaction and temperature

Answer

The relationship between the equilibrium constant of a reaction and temperature

Question 25

Given the rate law: Rate = k[A]^2[B], what is the order of the reaction with respect to A?

Accepted Answer

Second order

Answer

Zero order

Answer

First order

Answer

Cannot be determined

Question 26

Define activation energy in the context of chemical reactions.

Accepted Answer

Minimum energy required for a reaction to occur

Answer

Energy released during a reaction

Answer

Rate constant of a reaction

Answer

Concentration of reactants for a reaction to occur

Question 27

Which is NOT a method to increase the rate of a reaction?

Accepted Answer

Decreasing the surface area of reactants

Answer

Raising the temperature

Answer

Adding a catalyst

Answer

Increasing the concentration of reactants

Question 28

Define the half-life of a reaction.

Accepted Answer

Time taken for half of the reactants to be consumed

Answer

Time taken for the reaction to reach equilibrium

Answer

Rate constant of the reaction

Answer

Activation energy of the reaction

Question 29

Describe a characteristic of a zero-order reaction.

Accepted Answer

Constant reaction rate

Answer

Reaction rate proportional to reactant concentration

Answer

Zero activation energy

Answer

Half-life depends on the initial concentration

Question 30

How does a catalyst impact the activation energy of a reaction?

Accepted Answer

Lowers it

Answer

Raises it

Answer

No effect

Answer

Depends on the catalyst and reaction

Question 31

For a reaction with the rate law rate = k[A]^2[B], determine the reaction order with respect to reactant A?

Accepted Answer

2

Answer

0

Answer

1

Answer

3

Question 32

Identify the unimolecular mechanism among the following options:

Accepted Answer

A -> B + C

Answer

A + B -> C

Answer

A + B + C -> D

Answer

A + A -> B

Question 33

Define the activation energy for a reaction and state whether the following statement is true: 'Activation energy is always positive.'

Accepted Answer

True

Answer

False

Question 34

Which statement about catalysts is incorrect?

Accepted Answer

Catalysts are consumed in a reaction.

Answer

Catalysts increase the reaction rate.

Answer

Catalysts lower the activation energy of a reaction.

Answer

Catalysts can be either homogeneous or heterogeneous.

Question 35

Which technique is commonly used to study the kinetics of fast reactions?

Accepted Answer

Stopped-flow spectrophotometry

Answer

Potentiometry

Answer

Titration

Answer

Gas chromatography