## Spontaneous Reactions

$\Delta G^{\circ}= \Delta H^{\circ} - T \Delta S^{\circ}$

$\Delta G^{\circ}= -RT\ln K$

$\Delta G^{\circ}= \sum \Delta G_{f}^{\circ}(products) - \sum \Delta G_{f}^{\circ}(reactants)$

abram_wassily_1G
Posts: 10
Joined: Wed Sep 21, 2016 2:56 pm

### Spontaneous Reactions

Why does a negative value for the change in Gibbs's Free Energy for a specific reaction indicate that this specific reaction is spontaneous? Thanks.

Arianna_Mandelli_3C
Posts: 10
Joined: Wed Sep 21, 2016 2:58 pm

### Re: Spontaneous Reactions

The equation of change in Gibbs free energy is delta G=delta H-T*delta S. A negative delta G value may result from a large negative delta H, which corresponds to a large increase in the entropy of the surroundings. A negative delta G value may occur even if delta H is positive, as long as the T*delta S is positive and large enough. (The delta S refers to entropy.) In both cases, the negative G value results from an increase in entropy. So, the negative delta G indicates spontaneity because it also indicates an increase of disorder.