$\Delta G^{\circ} = -nFE_{cell}^{\circ}$

dtolentino1E
Posts: 101
Joined: Thu Jul 11, 2019 12:17 am

when we combine half-redox rxn like in Hess's law, why can't we also add together the E as if it was delta H?

Kimberly Koo 2I
Posts: 99
Joined: Sat Aug 17, 2019 12:17 am

This is because delta H is a state function while E is not. So delta H doesn't depend on anything but the initial and final state, which is why we can use Hess's law.

VPatankar_2L
Posts: 104
Joined: Thu Jul 25, 2019 12:17 am
Been upvoted: 1 time

Also, unlike in Hess' law where you could multiply the enthalpy values by the same coefficient that you multiplied the entire reaction by, you can't use the same strategy with cell potential. Standard reduction potential gives the voltage difference between two standard electrodes which is always the same. E* is an intensive property so it does not depend on the number of times the reaction occurs.

Lauren Tanaka 1A
Posts: 109
Joined: Sat Aug 17, 2019 12:18 am

Since E is not a state function you can't apply the same concepts that we used in Hess's Law. E is an intensive property too so no matter how many times the reaction occurs the E will not change.

rabiasumar2E
Posts: 108
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