The system’s response to these disturbances is described by Le Châtelier’s principle: An equilibrium system subjected to a disturbance will shift in a way that counters the disturbance and re-establishes equilibrium. A reversible reaction is at equilibrium when the forward and reverse processes occur at equal rates.

For a reaction at equilibrium, the composition is constant, and Q is called the equilibrium constant, K A homogeneous equilibrium is an equilibrium in which all components are in the same phase.

equilibrium — state of a reversible reaction in which the forward and reverse processes occur at equal rates. homogeneous equilibrium — an equilibrium in which all components are in the same phase. heterogeneous equilibrium — an equilibrium in which components are in two or more phases. composition — constant, and Q is called the equilibrium constant, K.