Yes, copper(II) sulfate decomposes when heated. When copper(II) sulfate is heated strongly, it undergoes a chemical change called thermal decomposition. During thermal decomposition, the copper(II) sulfate compound breaks down into its constituent elements: copper(II) oxide and sulfur trioxide. The chemical equation for the thermal decomposition of copper(II) sulfate is:

CuSO4(s) → CuO(s) + SO3(g)

In this reaction, the solid copper(II) sulfate decomposes to form solid copper(II) oxide and sulfur trioxide gas. The decomposition temperature of copper(II) sulfate is approximately 650 degrees Celsius. At this temperature, the compound begins to decompose and release sulfur trioxide gas. The decomposition process continues until all of the copper(II) sulfate has been converted into copper(II) oxide and sulfur trioxide.