This problem is homework from a lab I did yesterday. Normally I would just ask my TA, but since it's homework I can't. I could email him, but I feel like I'll probably get a faster response if I post this here(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

Use the Nernst equation to determine the cell potential for the cell involving Ag+. This is from a voltaic cell I made using a copper anode and CuSO4 solution and a silver cathode and AgNO3, with a KNO3 solution as a salt bridge. I used a multimeter to calculate the cell potentials for other cells I built (using other metal cathodes and relevant solutions) because their concentrations were 1M, standard conditions. The AgNO3 was 0.1M so I need to use the Nernst equation to calculate cell potential (assuming all other factors, ex. temperature were standard).

Measured potential for the cell: -0.390V

Given oxidation potential for the copper half reaction: +0.34V

2. Relevant equations

The Nernst Equation:

E[tex]_{cell}[/tex] = E[tex]^{o}[/tex][tex]_{cell}[/tex] + 0.0592V(mol)/n * log[tex]_{10}[/tex]Q

Half reaction at the cathode:

Ag+(aq) + e- -> Ag(s), since [Ag+] = 0.1M, Q and n will both be 0.1

3. The attempt at a solution

Honestly, this comes down to me not understanding what the terms mean. I just started electrochemistry and I haven't been able to find a decent explanation of the terms online.

I'm not sure whether I need to solve for E[tex]^{o}[/tex][tex]_{cell}[/tex] (I did and got -0.982V) or E[tex]_{cell}[/tex] (I got +0.202V). Solving for E[tex]^{o}[/tex][tex]_{cell}[/tex] makes more sense, given my answer, since I know that silver is a poor reducing agent. It should give a negative answer of fairly high magnitude in relation to the other cells, which it did.

Basically what I'm asking is, E[tex]^{o}[/tex][tex]_{cell}[/tex] is the quantity I'm looking for...right? Is E[tex]_{cell}[/tex] the measured potential for a cell under non-standard conditions? Also, is my answer for E[tex]^{o}[/tex][tex]_{cell}[/tex] of a reasonable magnitude? Thanks.

EDIT: Looks like my subscripts were messed up somehow. I'm pretty sure you'll be able to figure out what I meant though.

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# Homework Help: Nernst Equation Problem

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