Equilibrium Expressions - Kp, Ka, Kb, Ksp, and Keq

A reversible reaction can occur in both the forward or reverse direction. This means that both products and reactants are being produced at the same time. When at equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction. In other words, the speed at which the products are produced equals the rate that the reactants are being formed. Also, there will be no change in the concentrations of the reactants or products because, as one unit is being produced, it is simultaneously being consumed by the reverse reaction. Therefore, the system will appear to be stopped in terms of change. They are not static, but in reality, both reactions are occurring and opposing each other. The ratio of the products to the reactants, known as an equilibrium expression, can be developed based on the coefficients and concentrations of both the products and reactants. This value, K, will have a definite numeric value at a given temperature and is known as the equilibrium constant. Every reaction has its own equilibrium constant.