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).
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.
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]