Question

How does enthalpy affect the spontaneity of a reaction?

Answer 1

`DeltaG=DeltaH - TDeltaS`

Explanation:

Spontaneity is governed by free energy `DeltaG`. The relationship between the change on free energy `DeltaG` and change on enthalpy `DeltaH` is:

`DeltaG=DeltaH - TDeltaS`
where `DeltaS` is the change on entropy.

For spontaneous processes, `DeltaG` has to be negative. In order to predict the sign of `DeltaG`, we will need to watch for the sign of `DeltaH` and the term `TDeltaS`. Here is a table that explains this:

Here is a video that explains this in details;