gibbs free energy

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chiddler

Full Member
10+ Year Member
G is the quantity of accessible energy in a system. Or "process initiating work" that is present, as wiki puts it.

What is this in contrast to? What is an example of non-accessible energy? Or non-process initiating work?

I'm trying to differentiate &#8710;H from &#8710;G.

On second thought, I don't think such a thing exists as non-accessible energy. In that case, what is the difference between H and G?

MedPR

Membership Revoked
Removed
G is the quantity of accessible energy in a system. Or "process initiating work" that is present, as wiki puts it.

What is this in contrast to? What is an example of non-accessible energy? Or non-process initiating work?

I'm trying to differentiate &#8710;H from &#8710;G.

On second thought, I don't think such a thing exists as non-accessible energy. In that case, what is the difference between H and G?

Looking at G=H-TS, you can see that H is a component of G. G is the amount of energy that can be derived from a given reaction, part of which comes from the enthalpy change.

I'm not sure if that helps, but I don't really know what else there is :/

dranet

Full Member
The MCAT seems to love this thermodynamic equation. The Gibbs Free Energy equation compares the before and after situations in a reaction, hence the Delta H and Delta S. Then it compares Enthalpy with Entropy to see who wins. The overall result of the comparisons is to find if a reaction is favourable or not. A -DeltaG indicates favourable/spontaneous. A +Delta G indicates the reaction is unfavourable. It not only comes up in thermodynamics it is in Electrochemistry too. Don't confuse exergonic with exothermal, and endogonic with endothermal. This is where the MCAT loves to confuse.