What is the cell potential of the following cell at 25 oC? Note Au is a passive electrode?

Question

What is the cell potential of the following cell at 25 degree C? Note Au is a passive electrode

Cu / Cu2+ (0.00850 M) // Cr3+ (0.230 M), Cr2O72- (0.0380), H1+ (1.00 M) / Au

Answer 1

The related standard reduction potentials are:
Cr2O7(2-) + 14H+ + 6e- ==> 2Cr(3+) + 7H2O, E° = +1.33 V
Cu(2+) + 2e- ==> Cu(s), E° = +0.337 V
Thus the reaction is:
Cr2O7(2-) + 14H+ + 3Cu(s) ==> 2Cr(3+) + 3Cu(2+) + 7H2O, E° = +0.993 V

Using Nernst equation:
E = E° + (0.0591/n)*log([Cr2O7(2-)]*[H+]^14 /{[Cr(3+)]^2*[Cu(2+)]^3})
= 0.993+(0.0591/6)*log(0.0380 /{0.230^2*0.00850^3})
= 1.05 (V)