Question

how is free energy related to entropy and enthalpy of a system?When enthalpy and entropy are favourable will the process be spontaneous or non spontaneous ?explain.

Answer 1

Dear User,
Gibb's Free Energy (ΔG) is related to Enthalpy(ΔH) and Entropy(ΔS) as:

ΔG = ΔH-TΔS

When enthalpy is favourable i.e. ΔH​​= -ve
and, entropy is favourable i.e. ΔS = +ve
Then, ΔG = (-) + (+) = -ve i.e. the reaction will be spontaneous.
Enthalpy can be favourable when the reaction is exothermic (ΔH​​= -ve) or endothermic (ΔH​​= +ve) but entropy is favourable only when ΔS = +ve.