Definition - What does Equilibrium Constant mean?
The Equilibrium Constant is the reaction quotient value in a chemical reaction when the reaction reaches equilibrium. It is independent of the analytical concentration of any product and reactant species in a mixture, but depends on the ionic strength and temperature. It is essential to know the Equilibrium Constant so as to understand various chemical systems and biochemical process like acid base homeostasis and oxygen transport by hemoglobin in blood in the human body.
Petropedia explains Equilibrium Constant
The ratio of the concentration of products to the concentration of reactants is referred to as Equilibrium Constant. It is obtained when a single reaction is allowed to proceed and reach to equilibrium and then the concentration of every molecule involved in the reaction is measured. After that the ratio of product concentration to the reactant concentration is created. As the concentration is calculated at equilibrium, the Equilibrium Constant remains same for given reaction independent of all initial concentrations that determine the rate.
To calculate the numeric values, we need to know two things:
- The balanced equation for the reaction system, which includes physical states of each species.
- The equilibrium pressure or concentration of each species which occurs in equilibrium expression or complete information for determining them.
The Equilibrium Constant value is calculated after these values have been substituted in equilibrium expression.