AP Chem Unit 7 Equilibrium

Chemical Equilibrium

A state in a reversible reaction where the rates of the forward and reverse reactions are equal and the concentrations of reactants and products remain unchanged.

Reversible Reactions

Chemical reactions in which products can react to re-form the reactants.

Dynamic Equilibrium

A state of balance where forward and reverse reactions continue at the same rate, resulting in constant concentrations of reactants and products.

Equilibrium Constant (K)

A numerical value that expresses the relationship between the concentrations of products and reactants at equilibrium for a reversible reaction.

Le Chatelier’s Principle

A principle stating that if a stress is applied to a system at equilibrium, the system will shift in the direction that reduces the stress.

Dissociation Reaction

The process by which a compound separates into its constituent ions in solution.

Solubility Product Constant (Ksp)

An equilibrium constant that applies to the solubility of sparingly soluble ionic compounds.

Reaction Quotient (Q)

A measure of the relative amounts of products and reactants present during a reaction at a given time, used to determine the direction a reaction will shift to reach equilibrium.

ICE Table

A table used to track the Initial concentrations, Change in concentrations, and Equilibrium concentrations of reactants and products in chemical reactions.

Equilibrium Expression

A mathematical equation that relates the concentrations of products and reactants at equilibrium, typically taking the form K = [products]^[coefficients] / [reactants]^[coefficients].

Acid-Base Equilibrium

The state at which the concentrations of acids and bases in a solution remain constant, typically expressed in terms of pH.

pH Scale

A logarithmic scale used to specify the acidity or basicity of an aqueous solution, ranging from 0 (acidic) to 14 (basic).

Buffer Solutions

Solutions that resist changes in pH when small amounts of acid or base are added, consisting of a weak acid and its conjugate base.

Strong Acids

Acids that completely dissociate in solution, resulting in a high concentration of H+ ions, e.g., hydrochloric acid (HCl).

Weak Acids

Acids that partially dissociate in solution, resulting in a lower concentration of H+ ions, e.g., acetic acid (CH₃COOH).

Strong Bases

Bases that completely dissociate in solution to produce a high concentration of OH- ions, e.g., sodium hydroxide (NaOH).

Weak Bases

Bases that partially dissociate in solution, resulting in a lower concentration of OH- ions, e.g., ammonia (NH₃).

Titration

A technique used to determine the concentration of an unknown acid or base solution by reacting it with a solution of known concentration.

Equivalence Point

The point in a titration at which the amount of titrant added is exactly enough to completely neutralize the analyte solution.

End Point

The point in a titration at which an indicator changes color, signaling that the reaction is complete.