What is the equilibrium constant and how does it relate to the concentrations of reactants and products?

The equilibrium constant is a measure of the extent of a chemical reaction at equilibrium.

At equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction. The equilibrium constant, denoted as Kc, is the ratio of the concentrations of the products to the concentrations of the reactants, each raised to their stoichiometric coefficients.

Kc = [products] / [reactants]

The value of Kc indicates the position of equilibrium. If Kc is greater than 1, the equilibrium lies towards the products, indicating that the forward reaction is favoured. If Kc is less than 1, the equilibrium lies towards the reactants, indicating that the reverse reaction is favoured. If Kc is equal to 1, the concentrations of the reactants and products are equal, indicating that the reaction is at equilibrium.

The equilibrium constant can also be used to calculate the concentrations of reactants and products at equilibrium, given the initial concentrations and the stoichiometry of the reaction. This is useful in predicting the yield of a reaction and in designing chemical processes.

In summary, the equilibrium constant is a measure of the extent of a chemical reaction at equilibrium, and is related to the concentrations of the reactants and products. Its value indicates the position of equilibrium, and can be used to calculate the concentrations of reactants and products at equilibrium.