### Favorable Reactions

Posted: **Sun Jan 29, 2017 7:44 pm**

by **Leia_Acosta_1D**

On page 39 of the course reader, it says

delta S + favors forward processes

delta H+ endothermic does not favor forward process

Can someone please explain why this is the case?

### Re: Favorable Reactions

Posted: **Sun Jan 29, 2017 8:16 pm**

by **Ranica Hortelano 2D**

In order for delta G to be negative (which entails that the reaction is spontaneous) you want delta S to be positive. If delta S is negative, the whole equation, delta H minus T times delta S, would be positive; delta G would be positive, thus the reaction would be non spontaneous.

For delta S, if you have a reaction that has more molecules/moles of product than reactants, then you have an increase in entropy.

When you have a forward process for delta H you are creating more product (formation of bonds) and so there is a release of energy; delta H is negative because energy is released and we want delta H to be positive if we want a spontaneous reaction.

As long as your -T times delta S term is a large negative number and delta H is positive, your delta G will be negative, hence spontaneous.