## Gibb's Free energy

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

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

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

marcus lin 1E
Posts: 54
Joined: Fri Sep 28, 2018 12:28 am

### Gibb's Free energy

When is deltaG negative and positive? What's the significance?

Sean Reyes 1J
Posts: 67
Joined: Fri Sep 28, 2018 12:24 am

### Re: Gibb's Free energy

When delta G is negative, this signifies that a reaction will proceed spontaneously. If delta G is postive, this means that the reverse reaction will be spontaneous and the forward reaction will be non spontaneous. Delta G is guaranteed to be negative when delta H is negative and delta S is positive. If it’s the reverse (delta S is negative and delta H is positive), then the value of delta G will be positive. When the signs of delta H and delta S are the same, then the sign of delta G will be dependent on the temperature

Sarah Zhao 4C
Posts: 64
Joined: Fri Sep 28, 2018 12:28 am

### Re: Gibb's Free energy

Use the Gibb's Free Energy equation to determine spontaneity. While is is usually true that delta G follows the sign for delta H, please do not use this as a rule of thumb.

almaochoa2D
Posts: 67
Joined: Fri Sep 28, 2018 12:23 am

### Re: Gibb's Free energy

Delta G is spontaneity. From what I understand is if delta G is spontaneous it is also endothermic and if delta G is negative it is not spontaneous and it is exothermic.

505211599
Posts: 60
Joined: Fri Sep 28, 2018 12:28 am

### Re: Gibb's Free energy

delta g represents the spontaneity, so if it is negative it will be spontaneous and if positive it will be non-spontaneous.

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