# Is Gibbs energy negative?

##### 1 Answer

May 28, 2017

The change in Gibbs free energy is used to define if a certain reaction takes place spontaneously. You can calculate the change in Gibbs free energy with:

If you have

**A negative free energy change**

then you calculated the energy remainder, after the spontaneity of the process, that is free to use for other purposes.

**A positive free energy change**

then you calculated the minimum amount of energy needed to run the process spontaneously.

Remember: