This memory aid covers Memory Aid: Clean and Dirty Combustion within Combustion for GCSE Chemistry. Revise Combustion in Organic Chemistry for GCSE Chemistry with 25 exam-style questions and 15 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 9 of 13 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
🧠 Memory Aid: Clean and Dirty Combustion
Remember using the two types of Bunsen burner flame:
- Blue flame (air hole open) = Complete combustion → CO₂ + H₂O (CLEAN)
- Yellow flame (air hole closed) = Incomplete combustion → CO + C (DIRTY)
Also remember: Complete = CO₂ + H₂O (clean, safe), Incomplete = CO + C + H₂O (dirty, dangerous).
For balancing complete combustion equations, use the rule: Balance C first, then H, then O last (oxygens always come last because you can adjust O₂ freely).
Practice questions for Combustion
What are the only products formed during the complete combustion of a hydrocarbon?
Explain why carbon monoxide (CO) is toxic to humans. [3 marks]