APCE Kinetics & Chemical Equilibrium

Question 1

What is the rate of reaction?

Accepted Answer

The change in concentration of reactants or products per unit time.

Answer

The rate of reaction quantifies how quickly reactants are consumed or products are formed over a specific period. It is typically expressed as the change in molar concentration of a reactant or product divided by the time interval. This measurement helps understand the kinetics of a chemical process.

Question 2

What does Le Chatelier's Principle state?

Accepted Answer

The system will shift to minimize the disturbance.

Answer

Le Chatelier's Principle states that if a change of condition (like concentration, temperature, or pressure) is applied to a system at equilibrium, the system will shift in a direction that relieves the stress. This shift re-establishes a new equilibrium state, counteracting the initial disturbance.

Question 3

What factors affect the rate of reaction?

Accepted Answer

Concentration, temperature, surface area, and catalysts.

Answer

Several factors influence the rate at which a chemical reaction proceeds. Increasing reactant concentration or surface area leads to more frequent collisions, while higher temperatures increase collision energy and frequency. Catalysts speed up reactions by providing an alternative pathway with lower activation energy.

Question 4

What is activation energy?

Accepted Answer

The minimum energy required for a reaction to occur.

Answer

Activation energy is the minimum amount of energy that reactant molecules must possess to overcome the energy barrier and transform into products. It represents the energy required to break existing bonds and form an activated complex, allowing the reaction to proceed.

Question 5

What does the equilibrium constant (K) tell us about a reaction?

Accepted Answer

The relative concentrations of reactants and products at equilibrium.

Answer

The equilibrium constant (K) is a value that expresses the ratio of product concentrations to reactant concentrations at equilibrium, each raised to the power of their stoichiometric coefficients. A large K indicates that products are favored at equilibrium, while a small K indicates that reactants are favored. It provides insight into the extent of a reaction's completion.

AP Practice Test

AP Practice Test

APCE Kinetics & Chemical Equilibrium