Cue Column | Note Column

What is a galvanic cell? | Spontaneous electrochemical cell ($\Delta G$ < 0, E°cell > 0). Chemical energy → Electrical energy. Anode is NEGATIVE, cathode is POSITIVE.

What is an electrolytic cell? | Non-spontaneous cell requiring external power ($\Delta G$ > 0). Electrical energy → Chemical energy. Anode is POSITIVE, cathode is NEGATIVE.

E°cell formula? | E°cell = E°cathode − E°anode (always cathode MINUS anode)

Nernst equation at 25°C? | $E = E^\circ - \frac{0.0592}{n}\log Q$

At equilibrium? | E = 0, Q = K, therefore: $E^\circ = \frac{0.0592}{n}\log K$

$\Delta G$° and E°cell? | $\Delta G^\circ = -nFE^\circ$ where F = 96500 C/mol

Faraday's law? | $w = \frac{MIt}{nF}$ where M = molar mass, I = current (A), t = time (s), n = electrons

Molar conductivity? | $\Lambda_m = \frac{\kappa \times 1000}{M}$ units: S·$cm^{2}$/mol

Kohlrausch's law? | $\Lambda^\circ_m = \nu_+ \lambda^\circ_+ + \nu_- \lambda^\circ_-$

Degree of dissociation? | $\alpha = \frac{\Lambda_m}{\Lambda^\circ_m}$

Corrosion? | Anode (anodic spot): Fe → $Fe^{2+}$ + 2$e^{-}$; Cathode: $O_{2}$ + $2H_{2}O$ + 4$e^{-}$ → 4$OH^{-}$ → Rust: $Fe_{2}O_{3}$·x$H_{2}O$

Summary

The core equations are: E°cell = E°cath − E°an; Nernst E = E° − (0.0592/n)log Q; $\Delta G$° = −nFE°; w = MIt/(nF). Galvanic = spontaneous (anode negative); Electrolytic = non-spontaneous (anode positive). In BOTH, oxidation is at anode, reduction at cathode.