VCE Chemistry — Unit 3 AoS 2
Galvanic Cells — Flashcards & Quiz
Galvanic cells convert chemical energy into electrical energy through spontaneous redox reactions. In VCE Chemistry Unit 3 AoS 2, you study the components of a galvanic cell: the anode (oxidation), cathode (reduction), electrolyte solutions, and salt bridge. You need to draw and label cell diagrams, write half-equations, and calculate cell voltage from standard electrode potentials. Comparing galvanic cells to electrolytic cells is a common exam question, as is explaining the role of the salt bridge in maintaining electrical neutrality.
Sample Flashcards
Q1: Describe the structure and operation of a galvanic cell.
A galvanic cell converts chemical energy to electrical energy using a spontaneous redox reaction. Components: 1) Two half-cells, each with an electrode in a solution of its ions. 2) External circuit — electrons flow from anode (oxidation) to cathode (reduction). 3) Salt bridge — allows ion flow to maintain electrical neutrality (anions flow toward anode, cations toward cathode). The anode is negative (electron source); cathode is positive (electron sink).
Q2: What is the role of the salt bridge in a galvanic cell?
The salt bridge: 1) Completes the electrical circuit by allowing ion flow between half-cells. 2) Maintains electrical neutrality — as the anode solution gains positive ions (oxidation produces cations) and the cathode solution loses positive ions (reduction consumes cations), the salt bridge provides balancing ions. 3) Contains an inert electrolyte (e.g., KNO₃ or KCl) — anions migrate toward the anode, cations toward the cathode.
Q3: How does cell voltage relate to the spontaneity of a reaction?
Cell voltage (E°cell) indicates the driving force of the reaction. E°cell = E°cathode - E°anode. If E°cell > 0: reaction is spontaneous (galvanic cell — produces electricity). If E°cell < 0: reaction is non-spontaneous (requires external energy — electrolytic cell). If E°cell = 0: system is at equilibrium. Greater E°cell = greater driving force = reaction proceeds more readily. E°cell is related to Gibbs free energy: ΔG° = -nFE°cell.
Sample Quiz Questions
Q1: In a galvanic cell, oxidation occurs at the anode.
Answer: TRUE
In ALL electrochemical cells (galvanic and electrolytic), oxidation occurs at the anode and reduction occurs at the cathode. This is by definition — AN OX, RED CAT.
Q2: The salt bridge in a galvanic cell allows electron flow between the two half-cells.
Answer: FALSE
The salt bridge allows ION flow (not electron flow) to maintain electrical neutrality. Electrons flow through the EXTERNAL CIRCUIT (wire) from anode to cathode. The salt bridge provides counter-ions to balance charge.
Q3: E°cell for a galvanic cell is calculated as E°anode minus E°cathode.
Answer: FALSE
E°cell = E°CATHODE - E°ANODE (not the other way around). This gives a positive value for spontaneous galvanic cells because E°cathode > E°anode by definition.
Last updated: March 2026 · 3 flashcards · 3 quiz questions