## Nernst equation usage

$E_{cell} = E_{cell}^{\circ}-\frac{RT}{nF}\ln Q$

JennyCKim1J
Posts: 51
Joined: Fri Sep 29, 2017 7:04 am

### Nernst equation usage

Is Nernst equation simply used to find cell potential under non-standard conditions (not 1M)? I'm confused b/c there are different Nernst equations and I think one of them's supposed to be use to calculate k for redox reactions at equilibrium.

Daniisaacson2F
Posts: 30
Joined: Sat Jul 22, 2017 3:00 am

### Re: Nernst equation usage

Yes, you use it under nonstandard conditions, such as a change in the molarities (not 1M like you said), a different temperature, pressure, etc.

Sarkis Sislyan 1D
Posts: 31
Joined: Thu Jul 27, 2017 3:00 am

### Re: Nernst equation usage

The Nernst equation is used when finding the E under non-standard conditions. There are multiple versions of the equation, but they all mean the same thing and can be used interchangeably. I believe the equation you are talking about is E°=(RTlnK)/nF, which is pretty much the same thing again. This one can be derived by combining (delta)G°=-nfE° and (delta)G°=-RTlnK into nfE°=RTlnK and separating E°.

Elizabeth Bamishaye 2I
Posts: 54
Joined: Fri Sep 29, 2017 7:04 am

### Re: Nernst equation usage

Sarkis Sislyan 1D wrote:The Nernst equation is used when finding the E under non-standard conditions. There are multiple versions of the equation, but they all mean the same thing and can be used interchangeably. I believe the equation you are talking about is E°=(RTlnK)/nF, which is pretty much the same thing again. This one can be derived by combining (delta)G°=-nfE° and (delta)G°=-RTlnK into nfE°=RTlnK and separating E°.

I agree with this explanation!

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