## Calculating Cell Potential

Chloe Alviz 1E
Posts: 102
Joined: Sat Aug 17, 2019 12:17 am

### Calculating Cell Potential

What did Dr. Lavelle say was his "recommended" way of solving for the cell potential? He mentioned it during lecture earlier this week but I did not write it down :/

John Liang 2I
Posts: 102
Joined: Fri Aug 30, 2019 12:18 am

### Re: Calculating Cell Potential

Chloe Alviz 1E wrote:What did Dr. Lavelle say was his "recommended" way of solving for the cell potential? He mentioned it during lecture earlier this week but I did not write it down :/

he recommends:
1) identify the half rxns and look up E for each:

Fe3+ (aq) + e- = Fe2+ (aq) E=.77V
Cu2+ (aq) +2e- = Cu (s) E=.34 V

2) balance the the half rxns and write overall cell rxn (resembling Hess' method)
cathode: 2 Fe2+ +2e- = 2Fe2+ (E=.77V) (E doesn't change if coefficients do bc E is intensive property)
anode: Cu = Cu2+ + 2e- (E= -.34 V) (negative because the rxn flips)
redox rxn: 2 Fe2+ + Cu = Cu2+ (Ecell= .43V)

This is recommended by Lavelle because it shows the half rxns fully and balances the overall equation in one process, which is helpful since most exams will probably ask for each. Hope this helps!

Matt F
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

### Re: Calculating Cell Potential

John Liang 2I wrote:1) identify the half rxns and look up E for each:

Do you think there would be any cases where E is not given and we would have to calculate it given one of the formulas we have?