CBSE Class 11-science Answered

The Gibbs free energy of a system at any moment in time is defined as the enthalpy of the system minus the product of the temperature times the entropy of the system. The Gibb's free energy which is the maximum possible work done by the system.

G = H - TS

The Gibbs free energy of the system is a state function because it is defined in terms of thermodynamic properties that are state functions. The change in the Gibbs free energy of the system that occurs during a reaction is therefore equal to the change in the enthalpy of the system minus the change in the product of the temperature times the entropy of the system.

ΔG = ΔH - Δ(TS)

If G = Positive ,the system is non-spontaneous.

If G = Negative , the system is spontaneous.

If G = Zero, the system is in equilibrium.