Question

How to determine a temperature on which process is spontaneous by using function of Gibbs free energy?

Seems like this question can't be solved, maybe I just need any correlation between temperature and gibbs free energy?

Answer 1

If `Delta S>0`
`(Delta H) / (Delta S) < T`
If `Delta S<0`
`(Delta H) / (Delta S) > T`

Explanation:

`Delta G = Delta H - T Delta S`
G is gibbs free energy
H is enthalpy
S is entropy
`Delta G = - T Delta S_"net"`
If `Delta S_"net" < 0`
`DeltaG = - T Delta S_"net"<0(because T>0K)`, the process is spontaneous.

If `Delta H` and `Delta S` is given,
`Delta H - T Delta S<0`
`Delta H < T Delta S`
If `Delta S>0`
`(Delta H) / (Delta S) < T`
If `Delta S<0`
`(Delta H) / (Delta S) > T`