A chemical equilibrium constant is a measure of the extent to which a chemical reaction reaches equilibrium. It is a numerical value that represents the ratio of the concentrations of reactants and products at equilibrium.
The equilibrium constant, denoted as Kc, is calculated by taking the ratio of the products to reactants, with each concentration raised to the power of its respective coefficient in the balanced chemical equation. It can also be calculated using the partial pressures of gases, denoted as Kp.
The magnitude of the equilibrium constant indicates the direction of the reaction at equilibrium. If the value of K is large, it means that the reaction favors the formation of products at equilibrium. On the other hand, a small value of K indicates that the reaction favors the formation of reactants at equilibrium.
The equilibrium constant is affected by temperature according to the Van't Hoff equation. As temperature increases, the equilibrium constant also increases for endothermic reactions and decreases for exothermic reactions. This is because the equilibrium constant is a representation of the energy of the system at equilibrium.
The equilibrium constant is a constant value for a specific reaction at a given temperature. It cannot be changed unless the temperature is changed. However, the equilibrium composition of a reaction can be altered by changing the initial concentrations of reactants and products, which will in turn affect the value of the equilibrium constant.