# What is the difference between gibbs free energy and activation energy

1. Feb 3, 2014

### abi.ayan

what is actually meant by gibbs free energy and what is the difference between gibbs free energy and activation energy?In an enthalpy diagram how can it be denoted(just like for activation energy is denoted by the energy difference between transition state and reactants' enthalpy)?I just search through but couldn't get a clear idea about gibbs energy.can anyone explain with an simple example?

2. Feb 3, 2014

They have no similarities to begin with. As you have said, activation energy denotes the energy difference between transition state and reactants' enthalpy. But, Gibbs free energy is a term/ quantity whose dimensions happen to be that of energy.

ΔG = -TΔSuniverse = ΔH - TΔSsystem

And, as ΔSuniverse>0 for a spontaneous process, apparently ΔG<0.

So, it is just a quantity with the help of which we can say if a reaction proceeds forward or not.

The only way with which ΔG can be represented in an enthalpy diagram is through the relation

ΔG = ΔH - TΔS; where you can vary temperature and entropy.

Hope this explains it.
Best of luck!