This key facts covers Key Facts to Memorise within Electrolysis of Aluminium for GCSE Chemistry. Revise Electrolysis of Aluminium in Electrolysis for GCSE Chemistry with 20 exam-style questions and 0 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 7 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 7 of 12
Practice
20 questions
Recall
0 flashcards
📌 Key Facts to Memorise
- Bauxite is the ore containing aluminium oxide (Al₂O₃)
- Cryolite (Na₃AlF₆) lowers melting point from 2072°C to ~950°C — saves huge amounts of energy!
- Cathode half equation: Al³⁺ + 3e⁻ → Al (reduction — aluminium ions gain electrons)
- Anode half equation: 2O²⁻ → O₂ + 4e⁻ (oxidation — oxide ions lose electrons)
- Carbon anodes burn away because O₂ reacts with hot carbon: C + O₂ → CO₂
- Anodes need regular replacement — this is an ongoing cost of the process
- Electrolysis uses HUGE amounts of electricity — very expensive!
- Recycling aluminium saves 95% of the energy vs extracting from ore
- Aluminium is used in aircraft, drinks cans, power cables (low density + good electrical conductor)
- The cathode is made of steel (lined with carbon), the anodes are carbon/graphite
Quick Check: Why is cryolite added to the aluminium oxide in the Hall-Héroult process?
Cryolite lowers the melting point of aluminium oxide from 2072°C to approximately 950°C. This reduces the amount of energy (and therefore cost) needed to keep the mixture molten, making the process economically viable.