Ionic strength in calculations

[Michael Thornton]

Hello,

my question concerns the use of ionic strength within the calculation of ΔG.

How do you incorporate the ionic strength into the calculation of  ΔG?

From the source code I understand that extended Debye-Hückel is used like expected and the activity coefficient is used in the Legende transformation for each microspecies.

I would have expected the activity coeffient to appear in the reaction quotient Q of the overall equation ΔG = ΔG° + RTlnQ.

Maybe this is a trivial question.

Cheers and many thanks

Michael

[Elad Noor]

Hi Michael,

Sorry for the very late response.

The ionic strength is indeed going into the activity coefficients. We use Robert Alberty's notations, so the ΔG°  is transformed to incorporate the effect and we calculate Q using the unmodified concentrations (instead of using activities).

In the end, it is all equivalent, as far as I understand.

Best,

Elad