C20 - Electrochemistry (Gen. Chem 1)

half reaction

separates the oxidation and reduction reactions w/ transfer of e^-

balancing half-reactions

1. balance all but H & O

2. balance O w/ H₂O

3. balance H w/ H⁺

4. balance e^-

   *in basic solution, use OH^- rather than H⁺

voltaic cell

creates electricity through the transfer of e^- in a redox reaction

cathode

receives e^-, turning cations into solid metal

anode

donates e^- forming ions in solution

salt bridge

provides steady fuel of ions for e^- transfer in a voltaic cell

standard cell potential/emf

Eº_cell = Eº_red(cathode) - Eº_red(anode)

• + : spontaneous

• - : nonspontaneous

gibbs free energy & cell potential

∆G = -nFE

cell potential calculation from standard potential

E = Eº - (RT/nF)ln(Q)

• F = Faraday’s constant (9.65 × 10⁴ C/mol)