Key Definitions

Part of Electrolysis of Aluminium · Section 6 of 13

DefinitionsUnit: ElectrolysisGCSE

This definitions covers Key Definitions within Electrolysis of Aluminium for GCSE Chemistry. Revise Electrolysis of Aluminium in Electrolysis for GCSE Chemistry with 21 exam-style questions and 14 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 6 of 13 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.

📖 Key Definitions

Electrolysis: The decomposition of an ionic compound (when molten or in solution) using electrical energy to break down the compound into its elements.

Electrolyte: The ionic compound that is dissolved or melted to allow electrolysis to occur; it conducts electricity because its ions are free to move.

Cathode: The negative electrode in electrolysis; positive ions (cations) are attracted here and gain electrons (reduction occurs).

Anode: The positive electrode in electrolysis; negative ions (anions) are attracted here and lose electrons (oxidation occurs).

Cryolite: Sodium aluminium fluoride (Na₃AlF₆), used as a solvent for aluminium oxide in the Hall-Héroult process; it lowers the operating temperature from 2072°C to ~950°C.

Bauxite: The ore from which aluminium is obtained; it contains aluminium oxide (Al₂O₃) along with impurities.

Practice questions for Electrolysis of Aluminium

Why is aluminium extracted by electrolysis rather than by reduction with carbon?

  • A. Aluminium is less reactive than carbon
  • B. Aluminium is more reactive than carbon
  • C. Aluminium does not form ions
  • D. Carbon reacts with aluminium to form carbides
1 markfoundation

Explain why aluminium is extracted by electrolysis rather than by reduction with carbon.

2 marksstandard

Quick recall flashcards

Why do the carbon anodes need replacing regularly?
At 950°C, the oxygen produced at the anode reacts with the hot carbon: C + O₂ → CO₂. The carbon is gradually burned away, so the anodes must be replaced periodically.
What does OIL RIG stand for?
Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons). At the Anode = Oxidation (loss). At the Cathode = Reduction (gain).

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