Derive the empirical formula of a hydrocarbon that on analysis gave the following percentage by mass composition: C = 85.63 % and H = 14.37 %. If the molecular mass of this compound is 56 g, derive the molecular formula.

Answer 1

determine the mass in grams by treating the percentage values as masses (by mass composition)

calculate the mole of each element by mass/molar mass

divide each mole with the lowest mole and round off to whole number, to give you the empirical formula

to determine the molecular formula, just divide the molecular mass by the empirical mass.

hope that helps!!