Delta G units

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Bansi Amin 1D
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Delta G units

Postby Bansi Amin 1D » Sat Mar 17, 2018 8:28 pm

In the equation ΔG° = -nFE° we end up with units of joules while with the equation ∆G°=-RTlnK, we end up with units of joules per mole. How is this possible, and is there a way for ΔG° = -nFE° to yield units joules/mole?

Michele 2C
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Re: Delta G units

Postby Michele 2C » Sat Mar 17, 2018 9:01 pm

The answer to this can be found on page 571 of the textbook in the green box. The more technical form of the equation is written as ∆Gr = - nrFE where the subscript r represents the "molar" form where n is plugged in as just a number, without the mole units. So, if there were 2 moles, then you would plug in 2 to the equation, not 2 moles, so that the units of ∆G come out to be joules/mole. I'm not sure exactly when to use this versus the other form, but I just know that sometimes you have to do it this way.

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Re: Delta G units

Postby DamianW » Sun Mar 18, 2018 8:16 pm

-=spontaneous is also favorable right?

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Re: Delta G units

Postby ran2000 » Fri Feb 08, 2019 2:17 pm

G is always in terms of Joules. But the equation G=nFE is molarly dependent. Thus, the units are slightly different. But essentially, the conceptual idea is the same.

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