1. Waters of Hydration

2.  Some molecules exist in nature in relationship with water. Water just seems to be attracted to the molecules and it is possible to determine the number of water molecules relative to the number of molecules of the substance. These water molecules are called waters of hydration.

3. CaSO 4 2 H 2 O  For instance CaSO 4 2 H 2 O is the formula for gypsum, used in dry wall. There are two waters of hydration for every gypsum molecule. The proper name for this molecule is calcium sulfate dihydrate.

4.  CuSO 4 5 H 2 O copper (II) sulphate pentahydrate  Na 2 CO 3 10 H 2 O sodium carbonate decahydrate  CaSO 4 2 H 2 O calcium sulphate dihydrate

5. From the name, write the chemical formula:  Sodium sulphate decahydrate Na 2 SO 4 10 H 2 O  Magnesium sulphate heptahydrate MgSO 4 7 H 2 O