Final answer:
The equilibrium constant is a mathematical expression that represents the ratio of product concentrations to reactant concentrations at equilibrium. It is constant under given conditions.
Step-by-step explanation:
The equilibrium constant, denoted as Keq, is a mathematical expression that represents the ratio of the concentrations of the products to the concentrations of the reactants in a chemical reaction at equilibrium. It is constant under a given set of conditions. The equilibrium constant expression for the general chemical reaction aA + bB ⇆ cC + dD is written as [C]c[D]d / [A]a[B]b, where the square brackets represent the concentrations raised to the power of their coefficients in the balanced chemical equation.