## Gibbs Free Energy vs Internal Energy

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

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

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

Shirley Liu 2I
Posts: 64
Joined: Fri Sep 28, 2018 12:16 am

### Gibbs Free Energy vs Internal Energy

what is the difference between the two energies and do they have the same units? Internal energy is energy in a system that can do work but doesn’t gibbs free energy do work too? what is exactly meant by “free energy”?

Henry Krasner 1C
Posts: 64
Joined: Fri Sep 28, 2018 12:15 am

### Re: Gibbs Free Energy vs Internal Energy

Gibbs free energy is calculated by the enthalpy minus the entropy times absolute temperature of a system. Whereas the change in internal energy is work plus heat.

Andie Jian 1D
Posts: 69
Joined: Fri Sep 28, 2018 12:17 am
Been upvoted: 1 time

### Re: Gibbs Free Energy vs Internal Energy

I'm not entirely positive about this, but I think internal energy is more of a measure of the total energy of a system (which is why it can be changed by both work and heat). However, Gibbs free energy is a measure of only the energy that is available to be used. So, for example, during a reaction, some energy might be given off as heat because reactions can't be 100% efficient. Therefore, the product of that reaction will have less energy available inside of it to do work in the next reaction.

Nathaniel 2E
Posts: 27
Joined: Mon Jun 25, 2018 3:00 am

### Re: Gibbs Free Energy vs Internal Energy

Gibbs Free Energy is the maximum amount of non-expansion work that can be extracted from a thermodynamically closed system, a maximum that can be attained only in a completely reversible process. "Free energy" refers to energy available to do non-expansion work.