Question 1

Which of the following best describes the role of a catalyst in a chemical reaction?

Accepted Answer

A catalyst lowers the activation energy, increasing the rate of both the forward and reverse reactions.

Question 2

According to Le Chatelier's principle, what will happen if more $$\mathrm{CO_2$} is $$added to the following equilibrium at constant temperature?

$$\mathrm{$$CaCO_3$$(s) \rightleftharpoons CaO(s) + CO_2$(g)}$$

Accepted Answer

The equilibrium will shift to the left, producing more $$\mathrm{$$CaCO_3$$}.$$

Question 3

Which of the following changes will increase the rate of a reaction, assuming all other conditions are constant?

Accepted Answer

Adding a catalyst.

Question 4

For the reaction $$\mathrm{N_2O_4(g) \rightleftharpoons 2NO_2(g)}$$, which of the following will shift the equilibrium to the left?

Accepted Answer

Adding more $$\mathrm{NO_2$}$$ gas.

Question 5

Which statement about chemical equilibrium is correct?

Accepted Answer

At equilibrium, the forward and reverse reaction rates are equal.

Question 6

A reaction has an activation energy of $$50\ \mathrm{kJ/mol}. If a $$catalyst lowers the activation energy to $$30\ \mathrm{kJ/mol}$$, what is the most likely effect on the reaction rate?

Accepted Answer

The reaction rate will increase.

Question 7

Consider the following equilibrium: $$\mathrm{2SO_2(g) + O_2$(g) \rightleftharpoons 2SO_3(g)}. $$What will happen if the volume of the reaction vessel is decreased?

Accepted Answer

The equilibrium will shift to the right, favoring $$\mathrm{SO_3$}$$ formation.

Question 8

Which of the following best describes a reversible reaction?

Accepted Answer

A reaction in which products can react to reform reactants.

Question 9

In a medical scenario, a patient is given a drug that acts as a catalyst for a metabolic reaction. What is the expected effect on the patient's metabolism?

Accepted Answer

The metabolic reaction will speed up.

Question 10

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

Accepted Answer

Color of the reactants.

Question 11

For the reaction $$\mathrm{H_2$(g) + I_2$(g) \rightleftharpoons 2HI(g)}$$, what will happen if $$\mathrm{HI} is $$removed as it forms?

Accepted Answer

The equilibrium will shift to the right, producing more $$\mathrm{HI}.$$

Question 12

A student increases the concentration of reactants in a reaction at equilibrium. According to Le Chatelier's principle, what is the expected result?

Accepted Answer

The equilibrium will shift to produce more products.

Question 13

Which of the following best explains why increasing temperature generally increases the rate of a chemical reaction?

Accepted Answer

It increases the number of effective collisions between molecules.

Question 14

A reaction is at equilibrium. If a catalyst is added, what will happen to the concentrations of reactants and products?

Accepted Answer

The concentrations of reactants and products will remain unchanged.

Question 15

Which of the following is the correct equilibrium expression for the reaction $$\mathrm{N_2$(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)}$$?

Accepted Answer

$$K = \frac{[NH_3$]^2}{[N_2$][H_2$]^3}$$

Question 16

In the reaction $$\mathrm{2NO_2(g) \rightleftharpoons 2NO(g) + O_2$(g)}$$, what will happen if $$\mathrm{O_2$} is $$removed from the system?

Accepted Answer

The equilibrium will shift to the left.

Question 17

A reversible reaction is at equilibrium in a closed container. What will happen if the pressure is increased by decreasing the volume?

Accepted Answer

The equilibrium will shift toward the side with fewer moles of gas.

Question 18

Which of the following statements about equilibrium is FALSE?

Accepted Answer

At equilibrium, the reaction has stopped.

Question 19

A chemical reaction is exothermic. According to Le Chatelier's principle, what will happen if the temperature is increased?

Accepted Answer

The equilibrium will shift to favor the formation of reactants.

Question 20

Which of the following best describes the effect of removing a product from a system at equilibrium?

Accepted Answer

The equilibrium will shift to produce more product.

Chapter 10: Reaction Rates and Chemical Equilibrium – Study Guide

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