Electrochemistry
Galvanic cells, electrolytic cells, standard electrode potentials
Electrochemistry
Galvanic cells convert chemical energy to electrical energy through spontaneous redox reactions. Electrolytic cells use electricity to drive non-spontaneous reactions. Standard electrode potentials predict reaction direction and calculate cell EMF.
Example
Galvanic Cell
Zn/Cu cell: Anode (oxidation): Zn -> Zn2+ + 2e- (E0 = -0.76 V). Cathode (reduction): Cu2+ + 2e- -> Cu (E0 = +0.34 V). Cell EMF = 0.34 - (-0.76) = 1.10 V. Electrons flow from zinc to copper through external circuit.
Note
Exam Tip
An Ox and a Red Cat: Anode = Oxidation, Cathode = Reduction. In galvanic cells, anode is negative; in electrolytic cells, anode is positive. Use the Table of Standard Electrode Potentials.
Key Vocabulary
Galvanic cellAn electrochemical cell producing electricity from a spontaneous redox reaction
Electrolytic cellAn electrochemical cell using electricity to drive a non-spontaneous reaction
Standard electrode potentialThe voltage of a half-cell measured against the standard hydrogen electrode
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Galvanic cell
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