1. PG. 77 Hydrates

2. Hydrates are compounds that have water molecules attached to them. When determining the molar mass, you must account for the water. Ex. MgSO 4 7H 2 O Called anhydrous after water has been taken out

3. Naming Hydrates Name the compound and then use a prefix to describe the number of waters 1-mono, 2-di, 3-tri, etc. Add hydrate after the prefix (this means water) Ex. Ba(OH) 2 8H 2 O

4. Determining the formula for a hydrate 1. The mass of the compound will be given when it is both in hydrate form and anhydrous. Subtract the two. 2. This will tell you the mass of water in the compound. 3. Convert both masses (anhydrous and water) into moles 4. Find the ratio of moles of H 2 O to moles of the compound 5. The ratio tells you how many molecules of water there are

5. Example The mass of 2.50g hydrated copper sulfate (CuSO 4 xH 2 O) is placed in a crucible and heated. After heating 1.59 g white anhydrous copper sulfate remains. What is the formula for the hydrate. Name the hydrate.

6. Practice pg. 78 Pg. 337 #’s 55-57 Turn to page 349 in the book. Work problems 153, 154, 155