If a balanced reaction equation is not given you can determine the anode and cathode by comparing their E° values.
• ↓ E° → oxidation → anode
• ↑ E° → reduction → cathode
Cu2+ (aq) + 2 e- → Cu (s) E° = 0.34 V ↓ E° → oxidation → anode
Ag+ (aq) + e- → Ag (s) E° = 0.80 V ↑ E° → reduction → cathode
For the following electrochemical cell: Cu(s)/Cu2+(aq, 0.0155 M)//Ag+(aq, 2.50 M)/Ag(s)
write the net cell equation. Phases are optional. Do not include the concentrations. Calculate the following values at 25.0 degrees C using standard potentials as needed: Eknot cell (V), Delta Gknot reaction (kJ/mol), E cell (V), Delta G reaction (kJ/mol).
Ok so this is a question on my sapling homework and I entered:
Cu + 2Ag+ -> Cu2+ +2Ag (correct)
Eknot cell = Eknot red + Eknot ox: (0.80) + (-0.34) = 0.46 V (correct)
*Delta Gknot rxn = nFEknotcell: -2(96,485)(0.46) = -88766.2 J = -8877 kJ/mol (incorrect)
Delta G rxn = Delta Gknot rxn + RTln(Q): -88.77 + (8.3145 x 10-3)(298)[ln(0.155/(2.50)2)] = -103.69 kJ/mol (correct)
*E cell = (-Delta G rxn)/(nF): (-103.690)/[(2)(96485)] = 0.54 V or 0.5 V (incorrect)
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