PERCENTAGE COMPOSITION AND EMPIRICAL FORMULA
1. Find the percentage of oxygen in each of the following compounds:
a) N2O ________
b) C9H8O4 (aspirin) ________
2. A 1.23 g sample of copper metal is reacted completely with chlorine gas to produce
2.61 g of copper chloride. Determine the empirical formula of this chloride compound.
3. Freons are gases used as refrigerants. Chemical analysis shows that a certain Freon is
9.90% carbon, 58.70% chlorine and 31.40% fluorine by mass. Determine its empirical
4. Acetone is an important chemical solvent; a familiar home use is as nail polish remover.
Chemical analysis shows that acetone is 62.0% carbon, 10.4% hydrogen and 27.5%
oxygen by mass. Determine the empirical formula of acetone.
The g-molecular weight of acetone is shown to be 58.1 g/mole. What is the molecular
formula of acetone?
5. A 2.885 g sample of metal is reacted with oxygen to yield 3.365 g of the oxide M2O3 .
Compute the g-atomic weight of the element M.
6. A 2.00 g sample of bromine was reacted completely with excess fluorine. The mass
of the compound formed was 4.37 g. Determine its empirical formula.
7. Determine the empirical formula of gold chloride if a 126 mg sample contains 81.8 mg
8. A 0.709 g sample of iron reacts with HCl to give hydrogen gas and 1.610 g of a
compound containing iron and chlorine. Identify the product and write the balanced
equation for its formation.