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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: odicon on February 27, 2010, 11:04:21 PM

Title: Electrochemistry and potential difference
Post by: odicon on February 27, 2010, 11:04:21 PM

At 37^oC 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.

Title: Re: Electrochemistry and potential difference
Post by: Borek on February 28, 2010, 04:27:59 AM

Nernst.

Title: Re: Electrochemistry and potential difference
Post by: odicon 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.