Decomposition Reaction
A decomposition reaction is a reaction in which one compound breaks into two or more simpler substances.
Practice This ConceptMain explanation
Teacher explanation
Here, a single compound does not stay whole. It splits into simpler products because of heat, light, or electricity in many examples. The change is the opposite of combination.
Example
Heating calcium carbonate gives calcium oxide and carbon dioxide.
Simple analogy
Decompose means break apart.
Common confusion
Students sometimes think any reaction with one reactant is decomposition. The reactant must break into simpler products.
Exam tip
Look for one compound on the left and more than one product on the right.
Answer writing and exam use
1-mark use
Write the exact meaning of decomposition reaction in one clean line.
2-mark use
Define decomposition reaction and add one example or condition.
3-mark use
Explain decomposition reaction, show the method or example, and mention the common mistake.
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