Final answer:
The molecular formula of benzene is determined by dividing its molar mass (78.11 g/mol) by the mass of its empirical formula (CH, 13.01 g/mol), resulting in a factor of 6, which gives the molecular formula C6H6.
Step-by-step explanation:
The empirical formula of benzene is CH, which gives us the simplest whole number ratio of atoms within the molecule. To find the molecular formula, we compare the molar mass of the empirical formula (which is 13.01 g/mol for CH) with the actual molar mass of benzene, 78.11 g/mol. We divide the molar mass of benzene by the empirical formula mass to find the number of empirical units in the molecular formula:
(78.11 g/mol) / (13.01 g/mol) = 6
Therefore, the molecular formula of benzene is C6H6, as there are 6 times as many atoms of each element than in the empirical formula.