Question

Using appropriate equations and perhaps graphs, explain when free energy is relatively temperature independent.

Answer 1

For a physical change of ice melting is happened at constant temperature and also at constant pressure

G ∆H - T ∆S

If ∆G = < 0 process is spontaneous

∆G > 0 process is spontaneous in opposite direction

∆G = 0 Equilibrium

And also the changing free energy at constant temperature at change s in the concentration of the various species

G=G(T,P)= E--TS+pV= Gibbs free energy

dE = TdS --pdV

d(TS)--SdT--[d(pv)--VdP]

Or

dG = --SdT+Vdp----------1

But also dG = ( dG/dp )T dP + (dG/dT)P+ dT-----------2

From equation 1 & 2 ( dG/dp)T = V and (dG/dT)= -S

Finally -(dG/dP)T= (dV/dT)p ....it's Maxwell Relation.