Explanation
It can refer to Helmholtz free energy or Gibbs free energy/Gibbs function. Historically, in physics, free energy often refers to Helmholtz free energy; In chemistry, the free energy is often referred to as the Gibbs free energy. The ability of a material system to perform non volumetric work during constant temperature and constant volume processes and constant temperature and pressure processes can be characterized separately (to the maximum extent possible), which can serve as a criterion for the spontaneous progress of the process and the achievement of equilibrium. Helmholtz free energy and Gibbs free energy are state functions of thermodynamics system.
Classification
Fundamental of Material Science -> Physical and chemical basis of materials