1. Warm-Up! (Day 1) 1.What is the empirical formula of a compound that is composed of 0.608% Nitrogen and 1.388% Oxygen ? 2.What is the molecular formula if the compound from the above weighs 92.02g?

2. HYDRATES water

3. Hydrates: solid ionic compounds in which water molecules are trapped Opal: hydrated silica SiO 2nH 2 O

4. Formulas of Hydrates

5. Finding the Formula of Hydrates

6. 1.Need to dry out the sample Anhydrous= without water (dried substance) 2. Find the difference between the original and dried mass Mass of Hydrate – Mass of Anhydrous = Mass of Water 3. Convert the mass of water and dried substance to moles using the fence diagram 4. Divide both moles by the smaller number to get a ratio

7. Practice ◦ When 100g of hydrated BaBr 2 is dried, it weighs 89.2g. Find the formula of the hydrate.

8. Try these! (on a separate piece of paper) 1.When 100g of hydrated CaSO 3 is dried, it weighs 76.9g. Find the formula of the hydrate. 2.0.737g of MgSO 3 reacts with 0.763g of H 2 O to form a hydrate. Find its formula.