Question

Question #ddcb7

Answer 1

Basically, when heat is evolved, entropy is increasing. When heat is absorbed, entropy is decreasing.

A key relationship is the Gibbs Free Energy of Formation:
`Delta G = Delta H – t*Delta S`

Explanation:

Free energy is the energy available to do work. Thus, if a particular reaction is accompanied by a release of usable energy (that is, if `Delta G` is negative), this fact alone guarantees that it is spontaneous.

We can summarize the conditions for spontaneity and equilibrium at constant temperature and pressure in terms of `Delta G` as follows:

`Delta G < 0` The reaction is spontaneous in the forward direction.
`Delta G> 0` The reaction is non-spontaneous. The reaction is spontaneous in the opposite direction.
`Delta G = 0` The system is at equilibrium. There is no net change.