Question

copper carbonate on heating gives a black Residue of copper oxide

Answer 1

Some carbonates change colour during thermal decomposition, which means the compound breaks down into other substances when heated. Copper carbonate is green and becomes copper oxide which is black.

Answer 2

Heya user
Here's your answer !!

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Copper carbonate on heating dissociates to form two compounds , copper oxide and carbon dioxide .

CuCO3 -----> CuO ( black )+ CO2 .

Observation ----->
On heating Copper carbonate , a black residue is formed and a gas is released which turns lime water milky .
Thus , we can conclude that the gas evolved is carbon dioxide .

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Hope it helps !!