Copper II sulfate CuSO4 is a blue-colored salt that forms a blue solution when dissolved in water. When the solution is diluted, the color will become lighter blue due to the decrease in concentration of copper II ions. When the copper II sulfate solution is heated, the color may not change significantly unless the heating causes a chemical reaction or decomposition of the compound. In some cases, heating can cause the water of hydration to be removed from the copper II sulfate, forming anhydrous copper II sulfate, which is white. However, this typically occurs when the solid salt is heated, not when the solution is heated.If the solution is further diluted or heated to a higher temperature, the color will continue to become lighter blue due to the decrease in concentration of copper II ions. However, the color change due to heating will not be as significant as the color change due to dilution.