This deep dive covers Complete vs Incomplete Combustion within Combustion for GCSE Chemistry. Revise Combustion in Organic Chemistry for GCSE Chemistry with 20 exam-style questions and 15 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 2 of 12 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 2 of 12
Practice
20 questions
Recall
15 flashcards
⚗️ Complete vs Incomplete Combustion
Let's compare these two types of combustion using methane (CH₄):
CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l)
• Oxygen supply: Plentiful (excess oxygen)
• Flame: Blue, clean, hot
• Products: Carbon dioxide + water only
• Energy: Maximum energy released
• Safety: Safe products, just CO₂ and H₂O
2CH₄(g) + 3O₂(g) → 2CO(g) + 4H₂O(l)
OR
CH₄(g) + O₂(g) → C(s) + 2H₂O(l)
• Oxygen supply: Limited (insufficient oxygen)
• Flame: Yellow/orange, smoky, cooler
• Products: Carbon monoxide (CO) and/or carbon (soot)
• Energy: Less energy released
• Safety: Dangerous — CO is toxic!
⚠️ Carbon Monoxide Warning: CO is a colourless, odourless gas that binds to haemoglobin more strongly than oxygen. It prevents your blood from carrying oxygen, leading to unconsciousness and death. Never ignore yellow flames on gas appliances!