Here's why:

* Polar vs. Nonpolar: Copper sulfate is an ionic compound, meaning it's composed of charged ions (Cu²⁺ and SO₄²⁻). This makes it highly polar. Hexane, on the other hand, is a nonpolar solvent.

* "Like Dissolves Like": The principle "like dissolves like" governs solubility. Polar substances tend to dissolve in polar solvents, while nonpolar substances dissolve in nonpolar solvents. Since copper sulfate is polar and hexane is nonpolar, they are incompatible.

In summary: Due to their contrasting polarities, copper sulfate will not dissolve in hexane.