1. Lecture 59 Formulas of Hydrates Ozgur Unal 1

2.  What is the difference between the two fruits? 2  Can you find how much water was removed from the fruit?

3.  A hydrate is a compound that has a specific number of water molecules bound to its atoms.  Example: Epsom salt  MgSO4.7H2O  One epsom salt molecule has 7 water molecules and 1 MgSO4 formula unit. 3  In order to name hydrates we use prefixes  Table 10.1  Examples:  MgSO4.7H2O  magnesium sulfate heptahydrate  CaCl2.2H2O  Calcium chloride dihydrate  CuSO4.5H2O  copper (II) sulfate pentahydrate  Ba(OH)2.8H2O  ??  Na2CO3.10H2O  ??

4.  When a hydrate is heated, water molecules are driven off leaving an anhydrous compound (without water).  Check out Figure 10.17!!  How can we determine the formula of a hydrate? 4  Example: A mass of 2.5 g of blue, hydrated copper sulfate (CuSO4.xH2O) is placed in a crucible and heated. After heating, 1.58 g of white anhydrous copper sulfate (CuSO4) remains. What is the formula for the hydrate? Name the hydrate.  Example: An 11.75 g sample of a common hydrate of cobalt (II) chloride is heated. After heating, 0.0712 mol of anhydrous cobalt chloride remains. What is the formula and the name of this hydrate?