List the possible sources of energy required in decomposition reactions. Illustrate any one with a suitable example.
Generated by claude-sonnet-4-6 · 2026-06-14 10:30 · grounding rag
Model Answer
The possible sources of energy for decomposition reactions are:
- Heat (thermal decomposition)
- Light (photochemical decomposition)
- Electricity (electrolytic decomposition)
Example (Heat): When calcium carbonate is heated, it decomposes to form calcium oxide and carbon dioxide:
$$\text{CaCO}_3 \xrightarrow{\Delta} \text{CaO} + \text{CO}_2$$
Source: Chapter 1, Chemical Reactions and Equations
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Explanation
- The question has two parts: list sources (1 mark) and illustrate one with an example (1 mark). Name all three sources for full credit on the listing part.
- Any one correct example with a balanced equation earns the illustration mark — e.g., electrolysis of water or decomposition of silver chloride in sunlight are equally acceptable.
- Write the condition (heat symbol Δ, or "sunlight," or "electricity") above the arrow — examiners check for this.