Kinetics: The Study of Chemical Reaction Rates

Question 1

Which of the following is a catalyst?

Accepted Answer

Platinum

Answer

Sodium chloride

Answer

Hydrogen

Answer

Carbon dioxide

Question 2

What is the effect of increasing the temperature on the rate of a reaction?

Accepted Answer

Increases the rate

Answer

Decreases the rate

Answer

No effect on the rate

Answer

Reverses the reaction

Question 3

Which of the following is a spontaneous reaction?

Accepted Answer

A reaction with a negative ΔG°

Answer

A reaction that releases energy

Answer

A reaction that requires energy to occur

Answer

A reaction with a positive ΔG°

Question 4

What is activation energy and how does it affect the speed of a chemical reaction?

Accepted Answer

Activation energy is the minimum energy needed for a reaction to start.

Answer

Activation energy is the energy released during a reaction.

Answer

Activation energy is the energy of the products of a reaction.

Question 5

The rate of a reaction doubles for every 10°C increase in temperature. This relationship is described by which law?

Accepted Answer

Arrhenius equation

Answer

Ideal gas law

Answer

Law of conservation of mass

Answer

Le Chatelier's principle

Question 6

Which of the following is a catalyst?

Accepted Answer

Platinum

Answer

Sodium chloride

Answer

Iron oxide

Answer

Water

Question 7

The half-life of a reaction is the time it takes for the concentration of the reactant to decrease by:

Accepted Answer

50%

Answer

25%

Answer

75%

Answer

100%

Question 8

Which of the following is a unimolecular reaction?

Accepted Answer

A → B + C

Answer

A + B → C

Answer

A + A → B

Answer

A + B + C → D

Question 9

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

1

Answer

3

Question 10

Which of the following mechanisms is most likely for a reaction with a high activation energy?

Accepted Answer

Transition state theory

Answer

Collision theory

Answer

Chain reaction

Question 11

Which of the following is a homogeneous reaction?

Accepted Answer

Reactants and products are in the same phase

Answer

Reactants and products are in different phases

Answer

Reactants are in the gas phase and products are in the liquid phase

Question 12

The rate constant for a reaction is:

Accepted Answer

Dependent on temperature

Answer

Independent of temperature

Answer

Dependent on concentration

Answer

Equal to the activation energy

Question 13

Which of the following is a rate-determining step?

Accepted Answer

The slowest step in a reaction mechanism

Answer

The step with the lowest activation energy

Answer

The step that occurs first in a reaction mechanism

Answer

The step that produces the products

Question 14

Which factor does NOT affect the rate of a chemical reaction?

Accepted Answer

Surface area of reactants

Answer

Temperature

Answer

Concentration of reactants

Answer

Presence of a catalyst

Question 15

What is a rate law for a reaction?

Accepted Answer

An equation that expresses the relationship between the rate of reaction and the concentration of the reactants

Answer

A table that shows the half-lives of reactants

Answer

A graph that plots the concentration of reactants over time

Answer

A diagram that shows the activation energy of the reaction

Question 16

Which unit is used to express reaction rates?

Accepted Answer

mol/(dm³ s)

Answer

M/s

Answer

J/K

Answer

atm

Question 17

What describes a substance that can speed up a chemical reaction without being consumed?

Accepted Answer

A catalyst

Answer

A reactant

Answer

An inhibitor

Answer

An adsorbent

Question 18

What is the activation energy of a reaction?

Accepted Answer

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

Answer

The maximum amount of energy that can be released in a reaction

Answer

The average energy of the reactants

Answer

The energy of the products

Question 19

Which of the following is a characteristic of a zero-order reaction?

Accepted Answer

The rate of the reaction is independent of the concentration of the reactants.

Answer

The rate of the reaction is doubled when the concentration of the reactants is doubled.

Answer

The rate of the reaction is halved when the concentration of the reactants is halved.

Answer

The rate of the reaction is tripled when the concentration of the reactants is tripled.

Question 20

What is the half-life of a reaction?

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 double

Answer

The time it takes for the reaction to reach equilibrium

Answer

The time it takes for the reaction to complete

Question 21

What is an inhibitor?

Accepted Answer

A substance that slows down a chemical reaction

Answer

A substance that speeds up a chemical reaction

Answer

A substance that is consumed in a chemical reaction

Answer

A substance that is produced in a chemical reaction

Question 22

What is kinetics?

Accepted Answer

The study of the rates of chemical reactions

Answer

The study of the products of chemical reactions

Answer

The study of the mechanisms of chemical reactions

Answer

The study of the equilibrium of chemical reactions

Question 23

How does increasing the concentration of reactants impact the rate of a chemical reaction?

Accepted Answer

Speeds up the reaction

Answer

No change

Answer

Slows down the reaction

Answer

Cannot be determined without additional information

Question 24

How does a catalyst impact the activation energy of a chemical reaction and subsequently affect the reaction rate?

Accepted Answer

A catalyst lowers the activation energy, speeding up the reaction.

Answer

A catalyst increases the activation energy, slowing down the reaction.

Answer

A catalyst has no effect on the activation energy.

Question 25

In the potential energy diagram, which point indicates the transition state?

Accepted Answer

A. The peak of the diagram, where energy is highest

Answer

B. The bottom of the diagram, where energy is lowest

Answer

C. The point where reactants and products have equal energy

Question 26

Which of the following factors does NOT influence the rate of a chemical reaction?

Accepted Answer

Volume of the reaction mixture

Answer

Temperature

Answer

Concentration of reactants

Answer

Presence of a catalyst

Question 27

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

Accepted Answer

Decreases it

Answer

Increases it

Answer

Has no effect on it

Answer

Reverses it

Question 28

If doubling the concentration of a reactant quadruples the reaction rate, what is the order of the reaction with respect to that reactant?

Accepted Answer

Second order

Answer

First order

Answer

Zero order

Answer

Third order

Question 29

Which parameter in the Arrhenius equation is directly proportional to the activation energy of the reaction?

Accepted Answer

Ea

Answer

A

Answer

R

Answer

T

Question 30

In a reaction mechanism, which step determines the overall rate of the reaction?

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 31

Which factor does NOT influence the rate of a chemical reaction?

Accepted Answer

Gravity

Answer

Temperature

Answer

Concentration

Answer

Catalyst presence

Question 32

A catalyst is a substance that:

Accepted Answer

Lowers the activation energy of a reaction

Answer

Increases the activation energy of a reaction

Answer

Changes the products of a reaction

Answer

Is consumed in a reaction

Question 33

The rate law for a reaction is defined as: rate = k[A][B]^2. What is the reaction's order with respect to reactant B?

Accepted Answer

2

Answer

0

Answer

1

Answer

3

Question 34

Characterize a unimolecular reaction.

Accepted Answer

N2O5 → 2NO2

Answer

2NO + O2 → 2NO2

Answer

CH3CH2Br + NaOH → CH3CH2OH + NaBr

Answer

2H2 + O2 → 2H2O

Question 35

The half-life of a reaction is the time needed for the concentration of the reactant to drop by:

Accepted Answer

50%

Answer

25%

Answer

75%

Answer

100%

Question 36

Categorize a reaction where all reactants and products are in the same phase (e.g., aqueous or gaseous) as a:

Accepted Answer

Homogeneous reaction

Answer

Heterogeneous reaction

Answer

Endothermic reaction

Answer

Exothermic reaction

Question 37

Classify a reaction that occurs without any external input of energy:

Accepted Answer

Spontaneous reaction

Answer

Non-spontaneous reaction

Answer

Exothermic reaction

Answer

Endothermic reaction

Question 38

What happens to the rate of a reaction when you increase the surface area of a reactant?

Accepted Answer

The rate increases.

Answer

The rate decreases.

Answer

The rate stays the same.

Answer

It's impossible to tell.

Question 39

Which of the following is **NOT** a factor that affects the rate of a chemical reaction?

Accepted Answer

The color of the container

Answer

Concentration of reactants

Answer

Presence of a catalyst

Answer

Temperature

Question 40

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

Accepted Answer

Increasing the temperature

Answer

Adding an inhibitor

Answer

Decreasing the concentration of reactants

Question 41

Which of the following is **NOT** a characteristic of a catalyst?

Accepted Answer

They are consumed in the reaction

Answer

They increase the rate of the reaction

Answer

They are not consumed in the reaction

Question 42

Which of the following is the rate law for a first-order reaction?

Accepted Answer

Rate = k[A]

Answer

Rate = k[A]^2

Answer

Rate = k[A][B]

Answer

Rate = k[A][B]^2

Question 43

Which of the following is the integrated rate law for a second-order reaction?

Accepted Answer

1/[A]t = k[A]0t + 1/[A]0

Answer

ln[A]t = -kt + C

Answer

ln[A]t = ln[A]0 + kt

Answer

[A]t = [A]0 + kt

Question 44

Which of the following is the half-life of a first-order reaction?

Accepted Answer

t1/2 = ln2/k

Answer

t1/2 = ln2/[A]0

Answer

t1/2 = [A]0/k

Answer

t1/2 = k/[A]0

Question 45

Which of the following is the activation energy for a reaction?

Accepted Answer

The minimum energy required for a reaction to occur

Answer

The maximum energy that a reaction can reach

Answer

The energy released by a reaction

Question 46

Which of the following will shift the equilibrium position of a reaction to the right, favoring product formation?

Accepted Answer

Increasing the temperature

Answer

Decreasing the temperature

Answer

Decreasing the concentration of products

Answer

Increasing the concentration of reactants

Question 47

Which of the following is a homogeneous reaction?

Accepted Answer

A reaction in which the reactants and products are in the same phase

Answer

A reaction in which the reactants are solids and the products are gases

Answer

A reaction in which the reactants and products are in different phases

Question 48

Which of the following factors will NOT directly affect the rate of a chemical reaction?

Accepted Answer

The color of the reactants

Answer

Presence of a catalyst

Answer

Temperature

Answer

Concentration of reactants

Question 49

A reaction has a rate constant (k) of 0.05 s⁻¹. What does this tell us about the reaction's speed?

Accepted Answer

The reaction proceeds at a relatively slow rate.

Answer

The reaction is irreversible.

Answer

The reaction is very fast.

Answer

The reaction is at equilibrium.

Question 50

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

Accepted Answer

Second order

Answer

First order

Answer

Zero order

Question 51

A reaction has an activation energy (Ea) of 50 kJ/mol. What happens to the rate constant (k) if we increase the temperature?

Accepted Answer

The rate constant would increase.

Answer

The activation energy would decrease.

Answer

The rate constant would decrease.

Answer

The rate constant would remain unchanged.

Question 52

How does a catalyst speed up a chemical reaction?

Accepted Answer

By lowering the activation energy

Answer

By increasing the concentration of reactants

Answer

By increasing the temperature

Question 53

Consider the following reaction mechanism for the decomposition of ozone (O₃):

Step 1: O₃ → O₂ + O
Step 2: O + O₃ → 2O₂

What is the overall balanced chemical equation for this reaction?

Accepted Answer

2O₃ → 3O₂

Answer

O₃ + O₂ → 3O

Answer

O₂ + O → O₃

Question 54

Which of these is a key characteristic of an elementary reaction?

Accepted Answer

It occurs in a single step.

Answer

It involves a catalyst.

Answer

It is reversible.

Answer

It has a complex rate law.

Question 55

A reaction is first order with respect to reactant A. If we double the concentration of A, what happens to the reaction rate?

Accepted Answer

The rate will double.

Answer

The rate will be halved.

Answer

The rate will quadruple.

Answer

The rate will remain unchanged.

Question 56

The rate law for a reaction is Rate = k[A][B]. If we triple the concentrations of both A and B, how will the reaction rate change?

Accepted Answer

The rate will increase by a factor of 9.

Answer

The rate will decrease by a factor of 3.

Answer

The rate will remain unchanged.

Answer

The rate will increase by a factor of 3.

Question 57

The Arrhenius equation describes the relationship between the rate constant (k), activation energy (Ea), and temperature (T). Which statement about the Arrhenius equation is correct?

Accepted Answer

A higher activation energy leads to a lower rate constant at a given temperature.

Answer

A higher activation energy leads to a higher rate constant at a given temperature.

Answer

The rate constant is independent of temperature.