Question

What happens when copper carbonate is heated? Mention the type of reaction.

Answer 1

Copper carbonate or cupric carbonate is an ionic solid consisting of copper (II) cations $C{u^{2 + }}$ and carbonate anions $CO_3^{2 - }$ at ambient temperature. This compound is rarely encountered because it is difficult to prepare and readily reacts with water moisture from the air. This compound does not occur naturally and is synthesized only at high temperature and very high pressure.

Complete answer:
When copper carbonate is heated, it decomposes to form copper oxide and carbon dioxide.
$CuC{O_3}\xrightarrow{\Delta }CuO + C{O_2}(g)$
Thermal decomposition of the basic carbonate at atmospheric pressure yields copper (II) oxide $CuO$ rather than the carbonate. The colour of the compound changes from light green to a black one. Carbon dioxide gives a brisk effervescence on release.
This reaction is a decomposition reaction. Decomposition reactions occur when heat is applied to a pure substance and the particles rearrange into two or more new products.

Additional information:
Copper (II) carbonate can be made by reacting copper (II) salts with a carbonate or bicarbonate salt. This is most easily done by mixing saturated solutions of copper (II) sulphate and either sodium carbonate or sodium bicarbonate at a high temperature of around $500^\circ C$ and a pressure of $2GPa$ ($20000\;atm$).

Note:
Sometimes, copper (II) carbonate is confused with basic copper carbonate $C{u_2}{(OH)_2}C{O_3}$ also known as copper (II) carbonate hydroxide. For this reason, the qualifier neutral may be used instead of "basic" to refer specifically to $CuC{O_3}$. In the crystal structure of $CuC{O_3}$, copper adopts a distorted square pyramidal coordination environment with coordination number $5$. Each carbonate ion bonds to $5$ copper centres.