Mistake Master

Galvanic and Electrolytic Cells

An electrochemical cell separates a redox reaction into two half-reactions. A galvanic (voltaic) cell runs a spontaneous reaction to make electrical energy; an electrolytic cell uses an external power source to drive a nonspontaneous one. In both, oxidation is at the anode, reduction at the cathode; electrons flow through the wire from anode to cathode, and the salt bridge carries ions.

UNIT 9 TOPIC 9.8 • GALVANIC AND ELECTROLYTIC CELLS GALVANIC AND ELECTROLYTIC CELLS GALVANIC (VOLTAIC) CELL Spontaneous · ΔG < 0 · E°cell > 0 chemical energy → electrical energy V e⁻ flow salt bridge anions ← | → cations Zn Cu Zn²⁺ Cu²⁺ ANODE (−) CATHODE (+) oxidation (anode): Zn(s) → Zn²⁺(aq) + 2e⁻ reduction (cathode): Cu²⁺(aq) + 2e⁻ → Cu(s) Anions (Cl⁻) migrate toward the anode. Cations (K⁺) migrate toward the cathode. COMPARISON GALVANIC ELECTROLYTIC Spontaneity Spontaneous Nonspontaneous Thermodynamics ΔG < 0, E° > 0 ΔG > 0, E° < 0 Energy change chem → elec elec → chem Driven by itself (redox) external source Terminals anode −, cath + anode +, cath − Net result makes voltage needs voltage ELECTROLYTIC CELL Nonspontaneous · ΔG > 0 · E°cell < 0 electrical energy → chemical energy + e⁻ e⁻ power source electrolyte: NaCl(aq) ANODE (+) CATHODE (−) oxidation (anode): 2Cl⁻(aq) → Cl₂(g) + 2e⁻ reduction (cathode): 2H₂O(l) + 2e⁻ → H₂(g) + 2OH⁻(aq) Anions (Cl⁻) migrate toward the anode (+). Cations (Na⁺) migrate toward the cathode (−). KEY IDEAS e⁻: anode → cathode external circuit, both cells Anode = oxidation Cathode = reduction (always) Ions balance charge cations→cathode, anions→anode Voltage galvanic out, electrolytic in AP Chemistry · Unit 9 · Applications of Thermodynamics
A galvanic (voltaic) cell turns a spontaneous reaction into electrical energy; an electrolytic cell uses electrical energy to drive a nonspontaneous one. In both, oxidation occurs at the anode and reduction at the cathode; electrons flow through the external wire (anode → cathode) while the salt bridge carries ions.
Cell Builder · Open the sandbox →

The traps route electrons through the salt bridge (it carries ions; electrons go through the wire), send electrons the wrong way (anode → cathode), fix the anode by position, or assume an electrolytic cell runs on its own (it needs a power source). Anode = oxidation; cathode = reduction; wire for electrons, bridge for ions.

The work

3 ways in · any order
Lesson
Galvanic & Electrolytic Cells

Galvanic cells make electricity from spontaneous redox; electrolytic cells drive nonspontaneous redox with a power source; anode oxidizes, cathode reduces. The lesson wires the cell, then closes with a ten-scenario check.

Skill check · 10 scenarios
Diagnostic
10-item topic check

Ten items spanning the Topic 9.8 misconception: galvanic-cell setup — electron path, electrode roles, and the need for a power source in electrolysis.

Not started · 10 items · ~15 min
Targeted Practice
Drill a single misconception

Pick one of the failure modes you missed and drill it on its own. The round is adaptive: two correct in a row clears the misconception and moves you to the next.

Take the diagnostic to identify your misconceptions