Nernst equation

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Clara Cho 2K
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Nernst equation

Postby Clara Cho 2K » Mon Feb 24, 2020 8:12 am

Can you use the Nernst equation to determine if a reaction is at equilibrium?

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Re: Nernst equation

Postby Brian_Ho_2B » Mon Feb 24, 2020 8:40 am

The nernst equation wouldn't be the best equation to determine if a reaction, especially a redox reaction, is at equilibrium. If you're looking at a general equation, I'd recommend using the equations discussed in the second page of thermodynamics:
delta G = delta G not + RTln(Q)
at equilibrium, delta G not = -RTln(K)
ln(K) = -delta H not/RT + delta S not/R
ln(K2/K1) = -(delta H not/R)(1/T2 - 1/T1)
For equilibrium of redox reactions, I would use the equation that relates delta G and the cell potential, such as delta G = -nFE. At equilibrium, delta G is zero, so -nFE = 0 at equilibrium. That means at equilibrium, Ecell = 0.

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Re: Nernst equation

Postby Christineg1G » Mon Feb 24, 2020 9:00 am

The Nernst equation can be used to quantitatively determine the direction of electron transfer under non-standard conditions. Also, it has an important relation in determining a reaction's equilibrium constants and concentration potentials.

Return to “Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)”

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