Here's the symbol equation for the thermal decomposition of copper sulfate:

CuSO₄(s) → CuO(s) + SO₃(g)

Explanation:

* CuSO₄(s): Copper sulfate in its solid state (s)

* CuO(s): Copper oxide in its solid state (s)

* SO₃(g): Sulfur trioxide in its gaseous state (g)

What happens:

When heated strongly, copper sulfate (blue crystals) decomposes into black copper oxide and sulfur trioxide gas. The sulfur trioxide is released as a pungent gas.