A shiny brown coloured element ‘x’ on heating in air becomes black in colour. Name the element ‘x’ and the black coloured compound formed.

A shiny brown coloured element ‘x’ on heating in air becomes black in colour. Name the element ‘x’ and the black coloured compound formed.

Answer:

The element "X" is most likely copper (Cu). Copper has a characteristic reddish-brown color that appears shiny when it's freshly exposed. When heated in air, copper undergoes a reaction with oxygen. This reaction causes the copper to lose its shiny brown color and turn black. The new black compound formed is called copper oxide (CuO).

We can represent this reaction with a chemical equation: 2Cu (s) + O2 (g) → 2CuO (s). In this equation, 2Cu (s) represents two atoms of copper in their solid state. O2 (g) represents the oxygen gas present in the air. Finally, 2CuO (s) represents the two molecules of copper oxide formed after the reaction, which is also a solid.

Essentially, when heated, the shiny brown copper atoms bond with oxygen atoms from the surrounding air. This process, called oxidation, transforms the copper into black copper oxide.