## Nernst

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

Ian Morris 3C
Posts: 101
Joined: Wed Sep 18, 2019 12:18 am

### Nernst

When should we use logQ vs lnQ.

Maya Beal Dis 1D
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### Re: Nernst

If you are using the shortcut E=E(naught)-(0.05916/n)logQ, you need to use log. I think there is another number shortcut if you are using the equation with natural log.

605110118
Posts: 75
Joined: Wed Sep 18, 2019 12:21 am

### Re: Nernst

Ln is easier and often used more.

Matt Sanruk 2H
Posts: 131
Joined: Wed Sep 18, 2019 12:21 am

### Re: Nernst

Maya Beal Dis 1D wrote:If you are using the shortcut E=E(naught)-(0.05916/n)logQ, you need to use log. I think there is another number shortcut if you are using the equation with natural log.

Is this the equation given on the equation sheet?

Celine 1F
Posts: 120
Joined: Fri Aug 02, 2019 12:16 am

### Re: Nernst

I don't think I saw the shortcut equation with .05916 on the equations sheet so I used Ln

Daria MacAuslan 1H
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Joined: Sat Aug 17, 2019 12:16 am

### Re: Nernst

You usually use ln, just because it is more direct and it is also given to us on our equation sheets. If you want to use log however, just multiply by the conversion factor, it shouldn't really matter in the end

Katie Kyan 2K
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### Re: Nernst

You can use either but if you are trying to find the pH as in some of the HW problems, it would be easier to use the log version so you can find -log{H3O+].

Anthony Hatashita 4H
Posts: 103
Joined: Wed Sep 18, 2019 12:21 am

### Re: Nernst

You can use either, the equation sheet lists both so whichever you are most comfortable using is best.

Posts: 50
Joined: Tue Nov 05, 2019 12:18 am

### Re: Nernst

You can use whichever you want to use!

Ying Yan 1F
Posts: 101
Joined: Fri Aug 02, 2019 12:16 am

### Re: Nernst

When a problem is asking for you to solve for the pH or when you are given pH in a cell diagram, that's when you would usually use log instead of ln. Hope this helps!

205405339
Posts: 77
Joined: Thu Jul 11, 2019 12:16 am

### Re: Nernst

lnQ can always be converted to logQ thru the equation: lnQ=2.303logQ

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

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