Grade 12 chemistry - Chemical Equilibrium

Chemical equilibrium

The state of a reaction in which all reactants and products have reached constant concentrations in a closed system

Dynamic equilibrium

A balance between forward and reverse processes that are occurring simultaneously at equal rates

Equilibrium position

The relative concentrations of reactants and products in a system in dynamic equilibrium

Reversible reaction

A chemical reaction that proceeds in both the forward and reverse directions, setting up a equilibrium in a closed system

Equilibrium law

The mathematical description of a chemical system at equilibrium

Equilibrium constant

A constant numerical value defining the equilibrium law for a given system; units are not included when giving the value of K

Homogeneous equilibrium

A chemical equilibrium system in which all reactants and products are in the same state of matter, such as the gas state

Heterogeneous equilibrium

A chemical equilibrium system in which the reactants and products are present in at least two different states, such as gases and solids

Le Châtelier’s principle

A generalisation that states that chemical systems at equilibrium shift to restore equilibrium when a change occurs that distributes the equilibrium

Equilibrium shift

A change in concentrations of reactants and products in order to restore an equilibrium state

Ideal gas

A hypothetical gas composed of entities that have no size, travel in straight lines, and have no attraction to each other (no intermolecular forces); a gas that obeys all gas laws

Partial pressure

The pressure that a gas, in a mixture of gases, would exert if it alone occupied the whole volume occupied by the mixture

Reaction quotient

The product of the concentrations of the products, divided by the product of the concentrations of the reactants, for a chemical reaction that is not necessarily at equilibrium

Instantaneous concentrations

Concentrations that occur together at a particular point instant in time in the progress of a chemical reaction

Solubility

The quantity of solute that dissolved in a given quantity of solvent at a particular temperature; the concentration of a saturated solution at a particular temperature

Solubility equilibrium

A dynamic equilibrium between a solute and a solvent in a saturated solution in a closed system

Solubility product constant

The value obtained from the equilibrium law applied to a saturated solution

Trial ion product

The product of the concentrations of ions in a specific solution raised to powers equal to their coefficients in the balanced chemical equation; can be used to predict the formation of a precipitate

Common ion effect

A reduction in the solubility of an ionic compound due to the presence of a common ion in solution