Equilibrium Constant and Standard Free Energy Change Calculation

The Relationship Between Equilibrium Constant and Standard Free Energy Change

Equilibrium Constant (K): The equilibrium constant (K) of a reaction is a quantitative measure of the extent to which a reaction has reached equilibrium at a given temperature. It is determined by the concentrations of reactants and products at equilibrium and is a constant value at a specific temperature.

Standard Free Energy Change (ΔG°): The standard free energy change (ΔG°) of a reaction is a thermodynamic quantity that indicates the maximum amount of useful work that can be obtained from a reaction at standard conditions (1 atm pressure, 298 K temperature, and 1 M concentration).

Relationship between K and ΔG°: The equilibrium constant (K) and standard free energy change (ΔG°) are related through the equation ΔG° = -RT ln K, where R is the gas constant, T is the temperature in Kelvin, and ln K is the natural logarithm of the equilibrium constant. This equation allows us to calculate the standard free energy change for a reaction based on its equilibrium constant at a specific temperature.

Therefore, the equilibrium constant and standard free energy change are intricately linked in determining the thermodynamic feasibility and direction of a reaction.