5.11 1 26 'E': Standard Reduction Potential

G = G${}^0$ - RT$\ln$Q
Nernst eqation
$\Delta$E = E${}^0$ - $\frac{RT}{zF}\ln$Q
Cu${}^{2+} + 2e^-$ ⇔ Cu(s) @cathode Cu${}^{2+}$/Cu(s) 0.340
Zn(s) ⇔ Zn${}^{2+} + 2e^-$ @anode Zn${}^{2+}/Zn(s) -0.7628 "large negative->easy to reduce->good oxidizing agent"
step(1 $\Delta$E${}^0_{cell}$ = E${}^0$(cathode) - E${}^0$(anode) = 0.340 - (-0.7628) = 1.103[V] "... minus negative 0.7628 ..."
step(2 Q = $\frac{[Zn^{2+}]}{[Cu^{2+}]}$
oxidation@anode reduction@cathode
Electrolytic cell (decomposition) <-> Galvanic cell (battery)

Lec 26 | MIT 5.111 Principles of Chemical Science, Fall 2005