Empirical Formulas:

- Empirical Formulas are the simplest formula of a compound
- They only show the simplest ratio, not the actual atoms
- Molecular Formulas are the actua number of atoms
- To determine the empirical formula we need the ratio of each element
- to determine the ratio fill in the table below for each problem

e.g. Find the percentage composition of a compound that contains 17.6g of iron and 10.3g of sulfur. The total of the compound is 27.9

Fe 17.6g/27.9= 63.1 %
S 10.3/27.9=36.9 %

e.g. A compound was analyzed and was found to contain 9.8 g of nitrogen, 0.7 g of hydrogen, and 33.6 g of oxygen. What is the empirical formula of the compound?

N = 9.8g x 1mol/14.0g = 0.7 mol = 1
H = 0.7g x 1mol/1.0g = 0.7 mol = 1
O = 33.6g x 1mol/16.0g = 3 mol = 3

empirical formula: NHO3