* Decomposition: When you heat copper carbonate (CuCO₃), it breaks down into simpler substances: copper oxide (CuO), carbon dioxide (CO₂), and water (H₂O). This is a decomposition reaction.

* New Substances Formed: The original copper carbonate is no longer present. Instead, you have entirely different substances with different chemical compositions.

* Irreversible: The reaction is irreversible. You can't simply cool the copper oxide, carbon dioxide, and water to get back the original copper carbonate.

Here's the chemical equation for the reaction:

CuCO₃ (s) → CuO (s) + CO₂ (g) + H₂O (g)

Key takeaway: A chemical change involves the formation of new substances with different properties. Heating copper carbonate results in the formation of new substances, making it a chemical change.