Question

A
reaction occurs when one compound reacts and is broken down into different elements or simpler compounds.

Answer 1

You're describing a decomposition reaction. A clearer statement:

- A decomposition reaction occurs when a single compound breaks down into two or more simpler substances (elements and/or simpler compounds).
- General form: AB → A + B.

Key points and examples:
- Often requires energy input (heat, light, or electricity) and is frequently endothermic.
- Examples:
- Thermal decomposition: CaCO3 → CaO + CO2 (heating limestone)
- Electrolysis: 2 H2O(l) → 2 H2(g) + O2(g)
- Catalytic decomposition: 2 H2O2 → 2 H2O + O2 (decomposition of hydrogen peroxide, often sped up by a catalyst)

If you want, I can give more examples, show why some decompositions are endothermic, or compare decomposition with other reaction types.