## Indications

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

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

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

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Courtney McHargue 1I
Posts: 56
Joined: Fri Sep 28, 2018 12:17 am

### Indications

Are there any characteristics of a reaction that would hint at the value of delta G being positive/negative or larger/smaller?

Jessica Chen 1F
Posts: 61
Joined: Fri Sep 28, 2018 12:17 am

### Re: Indications

Since the equation to calculate for delta G is delta G = delta H - T(delta S), a small/negative delta H (enthalpy), large/positive T (temperature), and a large/positive S (entropy) would make for a very small/negative delta G.
The opposites would make delta G larger (more nonspontaneous).

megan blatt 2B
Posts: 61
Joined: Fri Sep 28, 2018 12:28 am

### Re: Indications

If a reaction is spontaneous, then delta G is negative. A very negative change in enthalpy (exothermic reaction) will likely cause delta G to be negative. A very positive change in entropy would likely also make delta G negative. Like the previous comment said, the opposite would then make delta G more positive and not spontaneous.

Emily Kennedy 4L
Posts: 57
Joined: Fri Sep 28, 2018 12:25 am
Been upvoted: 1 time

### Re: Indications

if you look in the txtbook there is a chart that does a good job of outlining this

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