1. Chemical equilibrium is a state in a chemical reaction where the rates of the forward and reverse reactions are equal. 2. At equilibrium, the concentrations of reactants and products remain constant over time, though both reactions continue to occur. 3. This balance means no net change in the amounts of substances involved. 4. The equilibrium can be described by the equilibrium constant $K$, which relates the concentrations of products and reactants at equilibrium. 5. Understanding chemical equilibrium helps predict the direction and extent of reactions in chemistry.