# Question #e2d82

There is a whole-number ratio of the number of water molecules per salt unit, such as $\text{FeCl"_3 * 6"H"_2"O}$ [iron(III) chloride hexahydrate] and $\text{CuSO"_4 * 5"H"_2"O}$ [copper(II) sulfate pentahydrate].