Work out standard cell potential instantly with clear inputs, formula shown and shareable results.
A cell's standard potential is the cathode's reduction potential minus the anode's, both taken from the standard reduction table without flipping signs. Copper against zinc gives 0.34 - (-0.76) = 1.10 V. The free energy follows from dG = -nFE, so that 1.10 V two-electron cell releases about 212 kJ/mol.
Cell potential
E(cell) = E(cathode) - E(anode)
Free energy
dG = -n x F x E(cell)
Because the subtraction already does it. Flipping the sign and then subtracting double-counts the reversal.
The reaction runs the other way spontaneously. Driving it as written makes it an electrolytic cell needing at least that voltage applied.