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### Topic: Electrochemistry and potential difference  (Read 5356 times)

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#### odicon

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##### Electrochemistry and potential difference
« on: February 27, 2010, 11:04:21 PM »
At 37oC the concentration of Fe3+ inside a cell is 0.082 M and outside is 0.016 M . The cell membrane is permeable to Fe3+. What potential difference in volts would have to exist across the membrane for Fe3+ to be in equilibrium at the stated conditions? Give you answer as the absolute value of the potential difference in volts.

Sorry if this is an easy question... but I do not quite know which equation I should be using for this one. Thanks a lot.

#### Borek

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##### Re: Electrochemistry and potential difference
« Reply #1 on: February 28, 2010, 04:27:59 AM »
Nernst.
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#### odicon

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##### Re: Electrochemistry and potential difference
« Reply #2 on: March 01, 2010, 01:05:00 AM »
Hi Borek,

Thanks a lot for your response!
I would really really appreciate it if you could help me set up Nernst equation for this one?

I set it as:

Delta E = RT/nF * ln([Fe3+ out]/[Fe3+ in])

and plugged in the values and got 0.0437 but the correct answer is 0.01459 so it must be wrong.

FYI
I plugged in:
R = 0.08206
T = 310
n = 1
F = 96485
[Fe3+ out] = 0.082
[Fe3+ in] = 0.016

but I am so lost.

Thanks a lot.