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### Topic: Nernst Equation Applied to Half-Reactions  (Read 5758 times)

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#### kaylaalicia

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##### Nernst Equation Applied to Half-Reactions
« on: March 23, 2009, 02:30:15 AM »
I'm not entirely sure how to incorporate the pH into the question.

Calculate the reduction potential (at 25°C) of the half-cell MnO4- (5.00×10-2 M)/ Mn2+ (3.60×10-2 M) at pH = 2.00.
(The half-reaction is MnO4- + 8H+ + 5e- --> Mn2+ + 4H2O.)

Using the equation Nernst equation, this is what I did. Although, since I didn't incorporate the pH into this. I'm positive that it's incorrect.
Eo= E-(0.0591/n) log Q

= 1.51 - (0.0591/5) log [(5.00E-2)/(3.60E-2)]
=1.51

For the pH, i know that 10-2 = [H+] = 0.01M

So help would be much appreciated

#### Borek

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##### Re: Nernst Equation Applied to Half-Reactions
« Reply #1 on: March 23, 2009, 04:09:29 AM »
What is Q? How does it look for the half reaction you have wrote?
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

#### kaylaalicia

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##### Re: Nernst Equation Applied to Half-Reactions
« Reply #2 on: March 23, 2009, 04:43:34 PM »
OH! I made such a stupid mistake. Thanks for that hint =]