The word equation for the decomposition of copper carbonate (CuCO₃) is:

Copper carbonate → Copper oxide + Carbon dioxide

Here's a more detailed breakdown:

* Copper carbonate (CuCO₃): This is the reactant, the substance being broken down.

* Copper oxide (CuO): This is one of the products, a black solid.

* Carbon dioxide (CO₂): This is the other product, a colorless gas.

This reaction is a decomposition reaction, meaning a single substance breaks down into two or more simpler substances. It typically occurs when heated.