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Finding Standard Potential Through Compiling Half-Reactions

Posted: Sat Feb 24, 2018 4:09 pm
by Emilie Hoffman 1E
Why can you assume that the deltaG of the final reaction is a composite of the deltaGs of the two other half reactions?

Re: Finding Standard Potential Through Compiling Half-Reactions

Posted: Sat Feb 24, 2018 4:15 pm
by Nhan Nguyen 2F
Gibbs free energy is a state function, which means that it takes in account of only the initial and final states of the system. Because it's a state function, we can assume that deltaGs of 2 half reactions can be added together to form the deltaG of the final reaction.

Re: Finding Standard Potential Through Compiling Half-Reactions

Posted: Sun Feb 25, 2018 12:06 pm
by Rachel Formaker 1E
Even though ΔG of a final reaction will be the sum of the ΔGs of its composite reactions, it is important to note that this is not true of standard potential, Eo.
Since Eo is not a state function, you must manipulate the equations to use ΔG, which is a state function.

If reaction 1 + reaction 1 = reaction 3,

Then,
ΔG3 = ΔG1 + ΔG2

and since ΔG = -nFEo,
-n3FEo3 = -n1FEo1 + (-n2FEo2)