Empirical and Molecular Formulas
1. A sample of lead arsenat contains 1.3813 g of lead, 0.00672 g of hydrogen, 0.4995 g of arsenic, and 0.4267 g of
oxygen. Calculate the empirical formula. (PbHAsO4)
2. Determine the molecular formulas of ibuprofen, a common headache remedy. Analysis yields a molar mass of
206 g/mol and a percent composition of 75.7% C, 8.80% H and 15.5% O. (C13H18O2)
3. Vanadium oxide is used as an industrial catalyst. The percent composition 56.0% V and 44.0% O. Determine the
empirical formula. (V2O5)
4. The hydrocarbon used in the manufacture of foam plastics is called styrene. Analysis of styrene indicates the
compound is 92.25% C and 7.75% H and has a molar mass of 104 g/mo. Determine the molecular formula for
styrene. (C8H8)
5. What is the empirical formula of a compound that contains 7.22 g Ni, 2.53g P, 5.25 g O. (Ni3P2O8)
6. Succinic acid is a substance produced by lichens. It is composed of 40.68% carbon, 5.08% hydrogen, 54.24%
oxygen and has a molar mass of 118.1 g/mol. What is the molecular formula? (C4H6O4).
7. Analysis of a compound containing chlorine and lead reveals that the compound is 59.37% lead. The molar mass
of the compound is 349.0 g/mol. What is the empirical formula and the molecular formula of this
compound?(PbCl4).
8. Glycerol is a thick, sweet liquid obtained as a byproduct of the manufacture of soap. Its percent composition is
39.12% C, 8.75% H, and 52.12% O. The molar mass is 92.11 g/mol. What is the molecular formula? (C3H8O3)