Law of Mass Action Expression/Equilibrium Constant Expression
The relationship between the concentrations of the reactants and products may be expressed using the law of mass action expression/equilibrium constant expression
General equilibrium reaction
1. [A]^a + [B]^b <=> [C]^c + [D]^d
2. Where [] is the concentration expressed in molarity
3. Keq is the equilibrium constant
Keq
If molar concentrations are used, Keq may also be referred to as Kc
Law of Mass Action
The ratio of the concentrations of the products raised to their respective stoichiometric coefficients to that of the reactants
Equilibrium constants for homogeneous gaseous equilibria
May also be expressed in terms of partial pressures
For equilibrium reactions where the reactants and products are in different phases (heterogeneous equilibria), pure solids and pure liquids are excluded in writing equilibrium constant expressions
