Law of Chemical Equilibrium Definition

Definition: The Law of Chemical Equilibrium is a relation stating that in a reaction mixture at equilibrium, there is a condition (given by the equilibrium constant, K_c) relating the concentrations of the reactants and products. For the reaction

aA(g) + bB(g) ↔ cC(g) + dD(g),
K_c = [ C ]^c·[ D ]^d / [ A ]^a·[ B ]^b