Chemical Equilibrium: A Comprehensive Guide for Associate of Arts in Liberal Arts Students

Question 1

According to Le Chatelier's principle, when an equilibrium system experiences stress, it will shift in a direction that:

Accepted Answer

Counteracts the applied stress

Answer

Enhances the applied stress

Answer

Has no effect on the stress

Answer

Predicts the rate of the reaction

Question 2

Which action will drive the equilibrium of the reaction N2 + 3H2 ⇌ 2NH3 towards the product side?

Accepted Answer

Increasing the temperature

Answer

Increasing the concentration of N2

Answer

Decreasing the concentration of H2

Answer

Adding a catalyst

Question 3

Which factor does NOT influence the equilibrium constant of a reaction?

Accepted Answer

Volume of the reaction vessel

Answer

Temperature

Answer

Concentration of reactants

Answer

Nature of the reactants

Question 4

Describe the primary function of a catalyst in a chemical reaction:

Accepted Answer

Decrease the activation energy of the reaction

Answer

Increase the activation energy of the reaction

Answer

Change the equilibrium constant of the reaction

Answer

Alter the products of the reaction

Question 5

Which of the following is NOT a classification of chemical equilibrium?

Accepted Answer

Static

Answer

Homogeneous

Answer

Heterogeneous

Answer

Dynamic

Question 6

Which of the following is the equilibrium constant expression for the reaction: A + B ⇌ C + D?

Accepted Answer

[A][B]/[C][D]

Answer

[C][D]/[A][B]

Answer

1/[A][B]

Answer

1/[C][D]

Question 7

According to Le Chatelier's principle, if the concentration of a reactant increases, the equilibrium will shift:

Accepted Answer

To the right

Answer

To the left

Answer

Not at all

Answer

Depends on the specific reaction

Question 8

What is the effect of increasing temperature on an exothermic reaction at equilibrium?

Accepted Answer

Shifts to the left

Answer

Shifts to the right

Answer

No effect

Answer

Depends on the pressure

Question 9

The equilibrium constant for a reaction is greater than 1. This indicates that:

Accepted Answer

The reaction favors the products

Answer

The reaction favors the reactants

Answer

The reaction is exothermic

Answer

The reaction is endothermic

Question 10

Which of the following is NOT a factor that can affect the position of equilibrium?

Accepted Answer

Nature of the solvent

Answer

Concentration of reactants

Answer

Temperature

Answer

Volume

Question 11

What is the equilibrium constant expression for the dissociation of a weak acid, HA?

Accepted Answer

Ka = [H+][A-]/[HA]

Answer

Ka = [HA]/[H+][A-]

Answer

Ka = [H+][A-]^2/HA

Answer

Ka = [HA]^2/[H+][A-]

Question 12

What is the relationship between the equilibrium constant and the Gibbs free energy change of a reaction?

Accepted Answer

Keq = exp(-ΔG0/RT)

Answer

ΔG0 = KeqRT

Answer

Keq = ΔG0RT

Answer

ΔG0 = Keq/RT

Question 13

Which of the following is an example of a heterogeneous equilibrium?

Accepted Answer

Ag+(aq) + Cl-(aq) ⇌ AgCl(s)

Answer

CO(g) + O2(g) ⇌ CO2(g)

Answer

H2(g) + I2(g) ⇌ 2HI(g)

Answer

CH3COOH(aq) + H2O(l) ⇌ CH3COO-(aq) + H3O+(aq)

Question 14

Which of the following conditions indicates a system at chemical equilibrium?

Accepted Answer

Reactants and products are being interconverted at equal rates, resulting in no net change in concentrations.

Answer

Reactants are continuously converting to products.

Answer

Products are continuously converting to reactants.

Answer

Reactants and products are not undergoing any interconversion.

Question 15

According to Le Chatelier's principle, which change will shift the equilibrium of the reaction A + B <=> C to the left?

Accepted Answer

Increasing the concentration of C

Answer

Increasing the concentration of A

Answer

Increasing the concentration of B

Answer

Decreasing the temperature

Question 16

A reaction has an equilibrium constant of 1. What does this imply?

Accepted Answer

The forward and reverse reactions occur at equal rates.

Answer

The reaction proceeds more in the forward direction than the reverse direction.

Answer

The reaction proceeds more in the reverse direction than the forward direction.

Answer

The reaction is not at equilibrium.

Question 17

Which of the following is commonly used as a catalyst in industrial processes?

Accepted Answer

Platinum

Answer

Sodium chloride

Answer

Water

Answer

Carbon dioxide

Question 18

What is the effect of adding an inert gas to a reaction at equilibrium?

Accepted Answer

Has no effect on the equilibrium

Answer

Shifts the equilibrium towards the side with more gas molecules

Answer

Shifts the equilibrium towards the side with fewer gas molecules

Answer

Changes the equilibrium constant

Question 19

What is the primary purpose of using a buffer solution in a chemical reaction?

Accepted Answer

To maintain a stable pH

Answer

To increase the reaction rate

Answer

To decrease the equilibrium constant

Answer

To prevent precipitation

Question 20

Which statement accurately describes chemical equilibrium?

Accepted Answer

The forward and reverse reactions occur at the same rate.

Answer

Reactants and products are present in unequal concentrations.

Answer

The concentrations of reactants and products are constantly changing.

Answer

The reaction proceeds completely in one direction.

Question 21

Which reaction is most likely to shift towards completion?

Accepted Answer

Reaction with a positive ΔH and large Keq

Answer

Reaction with a negative ΔG and small Keq

Answer

Reaction with a positive ΔS and small Keq

Answer

Reaction with a negative ΔS and large Keq

Question 22

The pH of a solution is directly related to its:

Accepted Answer

Hydrogen ion concentration

Answer

Hydroxide ion concentration

Answer

Concentration of both hydrogen and hydroxide ions

Answer

Neither hydrogen nor hydroxide ion concentration

Question 23

Which type of solution resists changes in pH upon small additions of acid or base?

Accepted Answer

Buffer solution

Answer

Neutral solution

Answer

Acidic solution

Answer

Basic solution

Question 24

The solubility product constant (Ksp) for a sparingly soluble salt represents:

Accepted Answer

The concentration of dissolved ions at equilibrium

Answer

The concentration of dissolved ions when the salt is completely dissolved

Answer

The minimum concentration of ions required to form a precipitate

Answer

The maximum concentration of ions that can exist in solution without precipitation

Question 25

Which factor has no influence on the reaction rate?

Accepted Answer

Volume of the container

Answer

Temperature

Answer

Concentration of reactants

Answer

Surface area of reactants (for solids)

Question 26

The equilibrium constant is a measure of:

Accepted Answer

Equilibrium position

Answer

Reaction spontaneity

Answer

Reaction rate

Answer

Activation energy

Question 27

Which of the following factors has no effect on the equilibrium constant of a reaction?

Accepted Answer

Size of the reaction vessel

Answer

Temperature

Answer

Pressure

Answer

Concentration of reactants

Question 28

In the reaction: 2NO(g) + O2(g) ⇌ 2NO2(g), how will the equilibrium shift if the partial pressure of NO is increased?

Accepted Answer

Right, favoring NO2

Answer

Left, favoring NO and O2

Answer

No shift

Answer

Insufficient information to determine

Question 29

Which of these reactions has the largest equilibrium constant?

Accepted Answer

E + F ⇌ G + H (Kc = 10)

Answer

A + B ⇌ C + D (Kc = 0.1)

Answer

I + J ⇌ K + L (Kc = 1)

Answer

M + N ⇌ O + P (Kc = 0.01)

Question 30

In the reaction: A(g) + B(g) ⇌ C(g), what happens to the equilibrium if the temperature is lowered?

Accepted Answer

Shifts left, favoring A and B

Answer

Shifts right, favoring C

Answer

No shift

Answer

The reaction will proceed to completion

Question 31

In the reaction: 2SO2(g) + O2(g) ⇌ 2SO3(g), what is the effect of adding a catalyst?

Accepted Answer

Increases the rate of the forward reaction

Answer

Increases the equilibrium constant

Answer

Increases the equilibrium concentrations of all reactants and products

Answer

Shifts the equilibrium towards SO2 and O2

Question 32

Which condition is NOT necessary for chemical equilibrium to be established?

Accepted Answer

The system is closed

Answer

Reactants and products are formed at equal rates

Answer

The concentrations of reactants and products remain constant over time

Answer

The forward and reverse reactions occur simultaneously

Question 33

The equilibrium constant for a reaction is 10. What is the ratio of [products] to [reactants] at equilibrium?

Accepted Answer

10:1

Answer

1:10

Answer

100:1

Answer

1:100

Question 34

Which of the following is an example of a homogeneous equilibrium?

Accepted Answer

Dissolving salt in water

Answer

Electrolysis of water

Answer

Combustion of methane

Answer

Precipitation of calcium carbonate

Question 35

Which of the following is an example of a buffer solution?

Accepted Answer

A mixture of a weak acid and its salt

Answer

A mixture of a strong acid and a strong base

Answer

A mixture of a weak base and a salt

Answer

A mixture of water and salt

Question 36

A solution has a pH of 7. What is the concentration of H+ ions in the solution?

Accepted Answer

10^-7 M

Answer

10^-14 M

Answer

1 M

Answer

10^-1 M

Question 37

Which of the following is a common ion effect?

Accepted Answer

The addition of a salt containing a common ion reduces the solubility of another salt

Answer

The addition of a strong acid increases the pH of a solution

Answer

The addition of a weak base decreases the conductivity of a solution

Answer

The addition of a catalyst decreases the activation energy of a reaction

Question 38

Which of the following statements about equilibrium is incorrect?

Accepted Answer

The concentrations of reactants and products do not change in equilibrium.

Answer

Equilibrium is a dynamic state where the forward and reverse reactions occur at equal rates.

Answer

Equilibrium can be achieved in both closed and open systems.

Answer

Equilibrium constants are temperature-dependent.

Question 39

Which of the following is a common ion effect?

Accepted Answer

The decrease in the solubility of a precipitate when a soluble salt containing a common ion is added.

Answer

The increase in the pH of a solution when a strong base is added.

Answer

The decrease in the rate of a reaction when a catalyst is added.

Answer

The increase in the boiling point of a solution when a nonvolatile solute is added.

Question 40

Which of the following factors does NOT affect the equilibrium constant of a reaction?

Accepted Answer

Volume of the reaction vessel

Answer

Temperature

Answer

Pressure

Answer

Concentration of reactants and products

Question 41

Which of the following reactions is at equilibrium?

Accepted Answer

2NO (g) <=> N2 (g) + O2 (g), K = 4.5 x 10^-31

Answer

CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g)

Answer

2H2 (g) + O2 (g) → 2H2O (l)

Answer

NH3 (g) + HCl (g) → NH4Cl (s)

Question 42

According to Le Chatelier's principle, what happens to the equilibrium position of an endothermic reaction when temperature is increased?

Accepted Answer

Equilibrium shifts to the product side

Answer

Equilibrium shifts to the reactant side

Answer

Equilibrium does not shift

Question 43

Consider the following equilibrium: 2SO2 (g) + O2 (g) <=> 2SO3 (g). What happens to the concentration of SO3 at equilibrium if more O2 is added?

Accepted Answer

Increases

Answer

Decreases

Answer

Remains the same

Answer

Cannot be determined

Question 44

Which of the following actions would increase the percent yield of NH3 in the reaction N2 (g) + 3H2 (g) <=> 2NH3 (g)?

Accepted Answer

Increase pressure and decrease temperature

Answer

Remove hydrogen

Answer

Add nitrogen

Answer

Increase temperature

Question 45

Which of the following substances is NOT a common catalyst for equilibrium reactions?

Accepted Answer

Hydrochloric acid

Answer

Nickel

Answer

Palladium

Answer

Platinum

Question 46

Which of the following is a defining characteristic of an equilibrium reaction?

Accepted Answer

Equal rates of forward and reverse reactions

Answer

Rapid attainment of equilibrium

Answer

Large equilibrium constant

Question 47

In a system at equilibrium, what is the relationship between the equilibrium constant and the Gibbs Free energy of the system?

Accepted Answer

The equilibrium constant is equal to the exponential of the negative Gibbs Free energy change divided by RT

Answer

The equilibrium constant is directly proportional to the Gibbs Free energy change

Answer

The equilibrium constant is inversely proportional to the Gibbs Free energy change

Question 48

Le Chatelier's principle predicts that a system at equilibrium will shift in the direction that:

Accepted Answer

Relieves the applied stress

Answer

Reverses the reaction

Answer

Increases the stress

Answer

Has no effect on the stress

Question 49

Which of the following is considered a weak acid?

Accepted Answer

Acetic acid

Answer

Sulfuric acid

Answer

Hydrochloric acid

Question 50

Which of the following is a buffer solution?

Accepted Answer

A solution containing a weak acid and its conjugate base

Answer

A solution containing a strong acid and a weak base

Answer

A solution containing a weak acid and a strong base

Question 51

The best way to prepare a buffer solution is to:

Accepted Answer

Mix a weak acid with its conjugate base

Answer

Mix a weak acid with a weak base

Answer

Mix a strong acid with a strong base

Answer

Mix a strong acid with a weak base