1. Bell Work: Interpret the Formula
How many of each element are in these compounds?
SO4
C3H8
CrO4-2
NH4+
Br2

2. Formula Mass
To find the formula mass of a compound, add up the masses of all parts of the formula
Example: CaF2

3. Formula mass: MgSO4

4. Formula mass: C5H12

5. Formula mass Find the formula mass of each of the following: KOH Fe2O3
CuPO C2H3O2-

6. Percent Composition Find how much of each element is in a compound

7. Percent Composition: CH2

8. Percent Composition: H2O

9. Percent Composition: NO3-

10. Percent Composition: AgC2H3O2

11. Bell Work Determine the formula mass of NaNO3
Find the percent composition of BaSO4

12. Percent Composition of Hydrates
Hydrates are substances that contain water as part of their formula
Examples: MgSO4 • 7H2O or Na2CO3 • 10H2O

13. Percent Composition of Hydrates
Find the percentage of water in the compound
CuSO4 • 5H2O

14. Percent Composition of Hydrates
A 5.0 g sample of a hydrate of BaCl2 was heated, and only 4.3 g of the anhydrous salt remained. What percentage of water was in the hydrate?