## Gibbs Free Energy

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

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

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

camrynpatterson3C
Posts: 44
Joined: Fri Sep 29, 2017 7:07 am

### Gibbs Free Energy

I'm still unsure as to exactly what Gibbs free energy is. I know it's expressed in terms of the difference between enthalpy and entropy, but is that all we can say about it? Is there nothing specific, like how enthalpy is heat and entropy is "disorder"?

Belle Calforda3f
Posts: 67
Joined: Fri Sep 29, 2017 7:07 am

### Re: Gibbs Free Energy

Gibbs free energy is a representation of spontaneity it the likeliness for which a reaction will occur on its own. So, as entropy can be called "disorder," Gibbs's free energy can be referred to as how spontaneous a reaction is. However, like "disorder," Dr. Lavelle does not love using spontaneity because students often assume this means quickness, but it has nothing to do with speed. It is just how likely or favorable a reaction will occur without help.

Helen Shi 1J
Posts: 78
Joined: Sat Jul 22, 2017 3:00 am

### Re: Gibbs Free Energy

Another way to think of entropy is the a state of relaxed disorder. Since Gibbs free energy is the amount of energy free do do work and the change in Gibbs is the energy that was needed to do work (or make a reaction happen) it is affected by the amt of heat or energy coming and leaving the system (which is enthalpy). Also if entropy isn’t very high, the change in Gibbs will be smaller and therefore spontaneous, because the more random the system more likely the molecules will meet and interact naturally.

Caroline LaPlaca
Posts: 30
Joined: Sat Jul 22, 2017 3:01 am

### Re: Gibbs Free Energy

Its a way to determine if a reaction will happen spontaneously

Wenjie Dong 2E
Posts: 53
Joined: Fri Jun 23, 2017 11:40 am

### Re: Gibbs Free Energy

"It measures the maximum or reversible work that may be performed by a thermodynamic system at a constant temperature and pressure. (isothermal, isobaric)"

Wenjie Dong 2E
Posts: 53
Joined: Fri Jun 23, 2017 11:40 am

### Re: Gibbs Free Energy

Wenjie Dong 2E wrote:"It measures the maximum or reversible work that may be performed by a thermodynamic system at a constant temperature and pressure. (isothermal, isobaric)"

from Wikipedia

Sophia Kim 1C
Posts: 51
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 1 time

### Re: Gibbs Free Energy

The way i think of it is that changing the state of a system requires energy (delta H) but when molecules exchange heat with its surroundings some molecules spontaneously arrange themselves so that the energy needed to change the state is less than the total energy required. The energy you actually have to put in is gibbs free energy that you added to the system.

Jessica Nunez 1I
Posts: 58
Joined: Thu Jul 13, 2017 3:00 am

### Re: Gibbs Free Energy

Gibbs free energy is amount of energy available to do work, and it can be used to predict whether a reaction will be spontaneous or not. If delta G is negative, then the reaction will be spontaneous in the forward reaction (meaning that the reactants have enough energy to move the reaction forward). If delta G is positive, then the reaction will not be spontaneous in the forward reaction (meaning that the products have more energy than the reactants).