## Finding Q

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

Justin Chu 1G
Posts: 52
Joined: Thu Jul 13, 2017 3:00 am
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### Finding Q

When would you know to use the lnQ or logQ equations when finding cell potential? For example, the problem 14.47, I used the equation for lnQ and got lnQ=15, but the answer says 10^6, which would only be possible if using the logQ equation.

Thu Uyen Tran 1B
Posts: 31
Joined: Fri Sep 29, 2017 7:05 am

### Re: Finding Q

I'm also confused with this one. When I exponentiated both sides to solve for Q, my answer was 3.27x106. Why does it only show 106 as the answer?

torieoishi1A
Posts: 32
Joined: Sat Jul 22, 2017 3:00 am

### Re: Finding Q

Using the Nernst equation with Ln and log should be interchangeable, but I had this same issue with this problem. I also got 3.27x10^6 rather than just 10^6.
There is an added constant for log. For ln: E = E-RT/nF(lnQ) but for log: E = E-2.303RT

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

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