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Topic: A little Nernst Clarification  (Read 1190 times)

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Offline discoclash

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A little Nernst Clarification
« on: May 02, 2019, 06:03:00 PM »
So I'm about to take the big ACS combined exam for my first gen chem classes and was hoping I could get a little clarification from someone.

When using the Nernst Equation, specifically when calculating the reaction quotient, do we include the H+ concentration?

Say my balanced equation is: (Cr2O7[2-]) + 14(H) + 6(MnO4[2-])  >  6(MnO4[-]) + 2(Cr[3+]) + 7(H2O)
And I've got ph: 4.50

Would I put a (10^-4.5)^14 in the denominator of the log Q portion  of the equation? It seems like that would take my Emeas down to a fraction of what it would be otherwise and that just doesn't seem right to me. Does the fact that the hydrogen will become liquid water mean anything?

Thanks

Offline Borek

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Re: A little Nernst Clarification
« Reply #1 on: May 03, 2019, 03:45:00 AM »
Would I put a (10^-4.5)^14 in the denominator of the log Q portion  of the equation?

Yes. Q is Q, no matter what.
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Offline discoclash

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Re: A little Nernst Clarification
« Reply #2 on: May 03, 2019, 02:54:02 PM »
Great, thank you!

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