Question

What change in color is observed when copper sulfate is heated? Is it a chemical change or a physical one?

Answer 1

Blue vitriol:

• Blue vitriol is a common name for hydrated Copper sulfate.
• The molecular formula of blue vitriol is ${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}$.
• It contains Copper sulfate along with $5$ molecules of water.

Heating blue vitriol:

• When blue vitriol or hydrated Copper sulfate solution is heated, it loses its water of crystallization and becomes anhydrous.
• The anhydrous form of Copper sulfate solution is ${\mathrm{CuSO}}_4$ and it is greyish-white in color.

A change in color depicts a chemical change. Thus, when copper sulfate is heated, a change in color is observed which is a chemical change.