Combustion (Edexcel IGCSE Chemistry)
Exam board Pearson Edexcel · IGCSEUpdated 2025-02-24
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Spec point — describe the combustion of elements in oxygen, including magnesium, hydrogen and sulfur
Combustion
What is combustion?
- Combustion is the scientific word for burning
- All combustion reactions involve a chemical change in which oxygen reacts with elements or compounds to produce oxides
- Combustion reactions give out heat, so they will always be exothermic reactions
- You need to be able to describe the combustion reactions of magnesium, hydrogen and sulfur
The combustion reactions of Mg, H2 & S
| Element | Observation during combustion | Symbol equation |
|---|---|---|
| Magnesium | Intense white flame White powder produced (magnesium oxide) | 2Mg (s) + O2 (g) → 2MgO (s) |
| Hydrogen | Exothermic Water is produced | 2H2 (g) + O2 (g) → 2H2O (g) |
| Sulfur | Blue flame Colourless, poisonous gas produced | S (s) + O2 (g) → SO2 (g) |
Exam Hint Combustion reactions can also be classified as oxidation reactions.
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