1. Percent Composition KMnO 4

2. Percent Composition (NH 4 ) 3 PO 4

3. Percent Composition HCl

4. Percent Composition Al 2 (SO 4 ) 3

5. Percent Composition Mg(NO 3 )

6. Percent Composition 1. How many grams of oxygen can be produced from the decomposition of 100.g of potassium chlorate (KClO 3 )?

7. Percent Composition 2. How much iron can be recovered from 25.0 g of Fe 2 O 3 ?

8. Percent Composition 3. How much silver can be produced from 125g of Ag 2 S?

9. Empirical Formula The smallest whole number ratio of elements in a compound Ex. H 2 O 2 has the empirical formula : The empirical formula for C 6 H 12 O 6 is : All ionic formulas are empirical

10. Molecular Formulas True formula- how the molecule actually exists It is a whole number multiple of the empirical formula

11. Label as empirical or molecular. - For the empirical formulas suggest possible molecular formulas. - For the molecular formulas, write the empirical formula. C 4 HO 2 C 22 H 44 O 11 CH 4 CaSO 4 Hg 2 Cl 2

12. Steps to calculate empirical formula 1.Convert amounts of all substance to moles 2.To get the simplest ratio, divide all moles by the smallest moles 3.If these numbers are round-able, round to the nearest whole number and make them the subscripts in the formula. (if there is a __.5 then multiply by 2 to get a round-able whole number) 1) 94.1%O, 5.9% H

13. Steps to calculate empirical formula 1.Convert amounts of all substance to moles 2.To get the simplest ratio, divide all moles by the smallest moles 3.If these numbers are round-able, round to the nearest whole number and make them the subscripts in the formula. (if there is a __.5 then multiply by 2 to get a round-able whole number) 2) A compound was analyzed and found to contain 13.5 g Ca, 10.8 g O, and 0.675 g H. What is the empirical formula of the compound?

14. To Calculate Molecular Formula (Empirical Formula) n n = 1)The molar mass of OH is 34.0 g/mol

15. To Calculate Molecular Formula (Empirical Formula) n n = 2) The empirical formula is C 2 H 4 S with a molar mass of 179 g/mol. What is the molecular formula?