Final answer:
To determine the molecular formula, first find the empirical formula and then calculate the ratio between the molar mass and the empirical formula mass.
Step-by-step explanation:
The molecular formula of a compound can be determined using the given information.
First, find the empirical formula by converting the percentages to moles. In this case, the compound is 92.3% carbon, so there would be 92.3 moles of carbon in 100 moles of the compound. Similarly, there would be 7.7 moles of hydrogen.
Next, divide the molar mass by the empirical formula mass to find the number of empirical formula units in a molecule. If the molar mass is 78.1 g/mol and the empirical formula mass is 26.0 g/mol (for C2H5), then the ratio is approximately 3.0. Therefore, the molecular formula would be (C2H5)3 = C6H15.