Thermodynamics and Thermochemistry
18.0 Free Energy (G)
18.0 Free Energy (G)
The available amount of energy during the process in the system which can be changed into maximum useful work is called the free energy of the system.
Thus, free energy change in the system $(?G),$ is the measure of the capability of doing useful work by the system.
$G=H-TS$ (Gibbs-Helmholtz equation)
At constant temperature, Gibb’s free energy change
$\Delta G = \Delta H - T\Delta S$
If $\Delta G = $ Negative, then the reaction is spontaneous
$\Delta G = 0,$ at equilibrium
$\Delta G = $ Positive, then the reaction is nonspontaneous
