Gibbs free energy, denoted by Δ, is a thermodynamic potential that measures the maximum amount of reversible work that can be performed by a thermodynamic system at constant temperature and pressure. It’s named after the American physicist Josiah Willard Gibbs. Gibbs free energy is particularly useful in determining the spontaneity and equilibrium of chemical reactions.
The formula for Gibbs free energy (Δ) is:
Where:
- = Gibbs free energy (in joules, J)
- = Enthalpy (in joules, J)
- = Temperature (in kelvin, K)
- = Entropy (in joules per kelvin, J/K)
The SI unit of Gibbs free energy is joules (J).