1. Hydrates
Chemistry

2. Hydrates
 A class of compounds containing chemically combined water. Usually, the water is loosely held and easily lost on heating.
Since the water is loosely held, it will evaporate or be pulled from the air depending on the vapor pressure of the chemical.
To write hydrates, use a dot:
CuSO4∙5H20

3. Efforescent hydrates – high vapor pressure, easily evaporate
Hygroscopic hydrates – low vapor pressure, take water from the air (dessicants)
Deliquescent substances will actually remove enough water from the air to dissolve themselves and form a solution.

4. Calculate the percent by mass of water in sodium carbonate decahydrate.

5. Na2CO3∙10H20
2Na = 46
C = X 100 = 62.9%
3O =
20H = 20
10O = 160
286 g
Calculate % water in copper (II) sulfate pentahydrate

6. CuSO4∙5H2O
Cu X 100 = 36% S
4O 64
5H20 90
250
Calculate % water in calcium chloride hexahydrate

7. CaCl2∙6H20
Ca X = %
2Cl
6H20 108
218