Question

Is Gibbs energy negative?

Answer 1

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:

`DeltaG=DeltaH-TxxDeltaS`

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:
`DeltaG<0` `color(blue)("Spontaneous")`
`DeltaG=0` `color(blue)("Reversible")`
`DeltaG>0` `color(blue)("Not spontaneous")`