1. FINDING EMPIRICAL AND CHEMICAL FORMULAS BY EXPERIMENT Chemistry 11 Ms. McGrath

2. Finding Empirical and Chemical Formulas by Experiment We know how to find percentage composition of a compound using its chemical formula. Often, the chemical formula is not known. Experimentation is then used to determine the percentage composition, molar mass then the chemical formula.

3. Finding Empirical and Chemical Formulas by Experiment Carbon- Hydrogen Combustion Analyzer An instrument that is used to analyze the amount of hydrogen, carbon and oxygen in important chemicals. It determines the percentage composition of compounds that are made up of these three elements.

4. Carbon- Hydrogen Combustion Analyzer

5. How does this work?

6. Carbon- Hydrogen Combustion Analyzer How does this work? Compounds containing carbon and hydrogen will burn in a stream of pure oxygen, O2, to produce only carbon dioxide and water. If a sample contains only carbon and hydrogen you can find the mass of the products (CO2 and H2O) separately to determine the mass percent of the compound.

7. Carbon- Hydrogen Combustion Analyzer

8. Example: A 1.000 g sample of a pure compound, containing only carbon and hydrogen, was combusted in an analyzer. The combustion produced 0.6919 g of water and 3.338 g of carbon dioxide. a)Calculate the mass of carbon and hydrogen in the sample. b)Find the empirical formula of the compound.