Number of molecules of water of crystallization in copper sulphate, sodium carbonate and Gypsum are

Water of crystallization refers to the fixed number of water molecules chemically bound to a salt in its crystalline form [1]. Copper sulphate typically exists as a pentahydrate, CuSO4·5H2O, meaning it contains 5 molecules of water [1]. Sodium carbonate, commonly known as washing soda in its hydrated form, is a decahydrate (Na2CO3·10H2O) containing 10 molecules of water [1]. Gypsum is chemically identified as calcium sulphate dihydrate (CaSO4·2H2O), which incorporates 2 molecules of water into its structure [1]. Therefore, the respective numbers of water molecules for copper sulphate, sodium carbonate, and gypsum are 5, 10, and 2. Heating these hydrated salts can remove this water, often resulting in a color change or loss of crystalline structure.

Sources

1. [1] https://eprints.whiterose.ac.uk/id/eprint/151850/10/Supplementary%20Material_31.05.19.pdf