1. Percent Composition and Chemical Formulas Chapter 10.3

2. Percent Composition It is sometimes useful to know a compound’s composition in terms of the masses of its elements. This is known as percent mass. % mass =

3. Percent Composition – Example Calculate the percent composition of titanium dioxide (TiO 2 )

4. Percent Composition – Example Calculate the percent composition of ammonium chloride (NH 4 Cl)

5. Percent Composition Extension – Example Calculate the mass of hydrogen in 15.2 g ammonium chloride.

6. Empirical Formulas Empirical formulas are the lowest whole-number ratio of the atoms in a compound

7. Molecular Formulas A molecular formula is a multiple of the empirical formula Empirical Formula - CH 2 O Molecular Formula – C 2 H 4 O 2 (Acetic Acid) Molecular Formula – C 3 H 6 O 3 (Lactic Acid) Molecular Formula – C 4 H 8 O 4 (1,4-dioxane-2,3-diol)