## Spontaneity

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

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

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

Lumbini Chandrasekera 1B
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

### Spontaneity

Given the value of Gibbs free energy, how do you know whether the reaction is spontaneous or not?

lindsey_ammann_4E
Posts: 61
Joined: Fri Sep 28, 2018 12:26 am

### Re: Spontaneity

You know a reaction is spontaneous when delta G is negative. If it's positive, the reaction is not spontaneous.

mahika_nayak_3L
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

### Re: Spontaneity

A reaction is spontaneous when the delta G value is negative. This indicates that the given reaction is favorable in that direction and will lead to a release in free energy, meaning that reactants have more free energy to do work than the products.

Michelle Nwufo 2G
Posts: 61
Joined: Fri May 18, 2018 3:00 am

### Re: Spontaneity

mahika_nayak_3L wrote:A reaction is spontaneous when the delta G value is negative. This indicates that the given reaction is favorable in that direction and will lead to a release in free energy, meaning that reactants have more free energy to do work than the products.

Why does a negative value for delta g indicate that a reacton is spontaneous?

Olivia Young 1A
Posts: 60
Joined: Fri Sep 28, 2018 12:24 am

### Re: Spontaneity

Another way of telling if the reaction is spontaneous is if the change in entropy of the universe is positive (deltaS universe). This is because deltaS universe is equal to -(deltaG)/T. As long as deltaG is negative, the resulting value which equals deltaS universe will be positive, since the temperature in Kelvins cannot be negative.