Question

What is the voltage and the Gibbs Free Energy for the following reaction? (Assume standard conditions)

3Sn^2+ (aq) + 2Al (s) --> 2 Al^3+ (aq) + 3 Sn (s)

Now calculate the Gibbs Free Energy for the above reaction if Sn^2+ (aq) is 0.15 and Al^3+ (aq) is 1.8

Answer 1

Look up reduction potential for Sn^2+.
Look up oxidation potential for Al.
Add the two potential for Ecell.

Using the reduction potential for Sn, plug in the values for concentration and recalculate E Sn.
For the Al, change the sign of the oxidation potential you had, plug in the concentration from the problem, calculate Ered for Al, then change the sign of that number.
Finally, add the two recalculated ox and red to find the new Ecell for the new concentrations.