Final answer:
The empirical formula of a hydrocarbon is the simplest whole-number ratio of carbon to hydrogen atoms and can be determined through combustion analysis, as exemplified by compounds like xylene and benzene.
Step-by-step explanation:
The empirical formula of a compound represents the simplest whole-number ratio of the elements within that compound. For hydrocarbons, the empirical formula can be found by determining the ratio of carbon to hydrogen atoms. In combustion analysis, the mass of CO₂ and H₂O produced allows the calculation of molar amounts of carbon and hydrogen, which in turn helps determine the empirical formula. As an example, xylene's empirical formula is C4H5, while its molecular formula is C8H10. Furthermore, the empirical formula of benzene is CH, despite its molecular formula being C6H6. When analyzing a compound with a known percentage of carbon, hydrogen, and oxygen, like a compound containing 40.0% C, 6.71% H, and 53.28% O, the resulting empirical formula could be CH₂O, demonstrating the lowest whole-number mole ratio of the elements.