Writing Equilibrium Constant Expressions

Heterogeneous equilibria involve reactions with compounds in different phases; multiple equilibria involve reactions with two or more steps.

Common reactions, such as the self-ionization of water, have specially named equilibrium constants.

The reaction quotient is a measure of the relative amounts of reactants and products during a chemical reaction at a given point in time.

For gas-phase reactions, the equilibrium constant can be expressed in terms of partial pressures, and is given the designation K_P.