11.83 6th ed // delta G equation  [ENDORSED]

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11.83 6th ed // delta G equation

Postby shaunajava2e » Mon Feb 25, 2019 3:43 pm

for 11.83 we need the delta G value,
the solution manual uses deltaG=deltaH - T* deltaS using values from appendix 2A, but can’t we just use the deltaG values from appendix 2A and use the deltaG= sum(deltaG products) - sum(deltaG reactants) ???
is there a reason they’re using the deltaH and deltaS to find deltaG?

i’ve attatched a picture of the problem and solution manual

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Re: 11.83 6th ed // delta G equation  [ENDORSED]

Postby Chem_Mod » Mon Feb 25, 2019 4:09 pm

You are correct; you can use either equation to calculate ∆G° at 25 °C, but just keep in mind that on an exam, you will need to know both methods as you may only be given the information to use one of the methods. For example, you may not be given the enthalpy or you may not be given the individual Gibb's Free Energy values.

The question also asks for ∆G° at 150 °C, so you will need to calculate the ∆H° and ∆S° anyway (and assume that they are temperature independent, which is usually a good approximation).

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