What is the meaning of Free_energy?

The energy available in a particular chemical system to do useful work. In more detail:

  1. Helmholtz free energy, A: the internal energy of a system minus the product of its entropy and absolute temperature.
  2. Gibbs free energy, G: the enthalpy of a system minus the product of its entropy and absolute temperature.

Helmholtz free energy, A: the internal energy of a system minus the product of its entropy and absolute temperature.

Gibbs free energy, G: the enthalpy of a system minus the product of its entropy and absolute temperature.

Used other than figuratively or idiomatically: see free, energy.

Source: wiktionary.org