Activation Energy

[KeiannaPineda1B]

What is the difference between activation energy and free energy of activation?

[Diana A 2L]

Free energy of activation is Gibbs free energy. This is referred to in terms of the energy barrier of a chemical reaction. Activation energy is the energy needed to surpass the barrier of the transition steps of a reaction.

The energy of activation is also the difference in energy between the (transition state and reactants) and the transition state and the intermediates.

Refer to the diagram attached. The delta Gc is the free activation energy for the catalyzed reaction.

HERES A BETTER DIAGRAM that makes a clearer distinction:

Hope that helps!

[Madelyn Romberg 1H]

Does this mean that free energy of activation measured without the enzyme? Or is it needed in relation to the activation energy with the enzyme?

[Diana A 2L]

Does this mean that free energy of activation measured without the enzyme? Or is it needed in relation to the activation energy with the enzyme?

Not exactly. It means that the free energy of activation is the, let's say, "left over" energy of activation in addition to the activation energy measured with the enzyme. Basically, the addition of the energy of activation measured WITH the enzyme and the energy of activation measured without the enzyme gives you the total energy of activation to get from the reactants to the transition state (which is the really high slope in the chart). I hope this offers SOME clarity, I know it's a bit confusing.