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12.2: Free Energy

Last updated

Jul 5, 2019
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- 12.1: Review of Internal Energy and Enthalpy
- 12.3: Helmholtz Free Energy

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We shall be learning that there are two sorts of free energy.

There is the Helmholtz free energy. Commonly used symbols for this are A (from the German die Arbeit – work) or F.

And there is the Gibbs free energy. Commonly used symbols for this are G − or F!

It is unfortunate that some writers will use simply the term "free energy”, using the symbol F, without specifying which, or even giving evidence that they are aware of the difference. I have seen the symbol F used about equally often for Helmholtz, Gibbs or unspecified free energies.

In these notes I shall use the symbol A for the Helmholtz free energy and G for the Gibbs free energy, and I shall avoid the symbol F.

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