AP Chemistry Unit 7: Advanced Equilibrium Concepts

Le Chatelier's Principle

A principle that predicts how a system at equilibrium responds to external changes.

Dynamic Equilibrium

A state where the rates of the forward and reverse reactions are equal, resulting in no net change.

Concentration Change

A method of stress on a system where adding or removing reactants/products causes a shift in equilibrium.

Pressure Change

A method of stress on gaseous systems where increasing or decreasing pressure affects the position of equilibrium.

Temperature Change

The only type of stress that changes the value of the equilibrium constant (K) of a reaction.

Exothermic Reaction

A reaction that releases heat, treated as a product in the context of Le Chatelier's Principle.

Endothermic Reaction

A reaction that absorbs heat, treated as a reactant in the context of Le Chatelier's Principle.

Reaction Quotient ($Q$)

A measure that compares the relative amounts of products and reactants at any point in a reaction.

Equilibrium Constant ($K$)

A numerical value that indicates the ratio of products to reactants at equilibrium.

Common-Ion Effect

The decrease in solubility of a salt when a common ion is added to the solution.

Solubility Product Constant ($K_{sp}$)

An equilibrium constant for the dissolution of a sparingly soluble ionic compound.

Molar Solubility ($s$)

The number of moles of a solid that dissolve in one liter of solution to reach saturation.

ICE Table

A chart used to calculate the concentrations of species in a reaction at equilibrium (Initial, Change, Equilibrium).

Hydronium Ion Formation

The process that occurs when an acid donates a proton, affecting the solubility of salts containing basic anions.

Thermodynamics

The study of heat and energy transfers in chemical reactions, including the dissolution of salts.

Gibbs Free Energy (ΔG)

A thermodynamic quantity used to predict the spontaneity of a reaction at constant temperature and pressure.

Entropy (ΔS)

A measure of disorder or randomness in a system, which is usually positive in dissolution processes.

Enthalpy (ΔH)

The heat content of a system, which can be either released or absorbed during a chemical reaction.

Standard Conditions

A set of conditions (usually 1 bar pressure and a specific temperature) used when reporting equilibrium constants.

Stoichiometry

The calculation of reactants and products in chemical reactions based on balanced equations.

Catalyst

A substance that speeds up a reaction without being consumed, affecting the rate but not the position of equilibrium.

Inert Gas

A gas that does not react with other substances in a chemical system and does not affect the shift in equilibrium.

Dissolution

The process in which a solid forms a solution by interacting with a solvent.

pH

A measure of the acidity or basicity of a solution, impacting the solubility of salts.

Acidic Solution

A solution with a higher concentration of hydrogen ions (H^+), affecting the solubility of basic salts.

Saturated Solution

A solution in which the maximum amount of solute has dissolved at a given temperature.