6N.5b - getting giant exponents/overflow?

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

Sue Bin Park 2I
Posts: 52
Joined: Mon Jun 17, 2019 7:24 am

6N.5b - getting giant exponents/overflow?

by balancing the redox reaction and using the resulting coefficients, i end up with crazy large exponents and my calculator gets overflow error...i'm not sure what i'm doing wrong? i multiply the reduction of MnO4- by 2 and the oxidation of Cl- by 5 to get 10 e- total

Angela Patel 2J
Posts: 110
Joined: Sat Aug 24, 2019 12:17 am

Re: 6N.5b - getting giant exponents/overflow?

You are using the right stoichiometric coefficients. You should get that the balanced MnO4- reduction reaction has an E0 of +1.51 V and the balanced Cl- oxidation reaction has an E0 of +1.36 V. You then combine the reactions and do E0 of the cathode minus the E0 of the anode and get a positive E0 for the cell. Then you plug that in to the Nernst equation and solve. There are some pretty large exponents in there but it might be helpful to do some simplification with the equation before plugging it directly in to the calculator.

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