First we have to find the empirical formula, empirical formula gives the simplest ratio of whole numbers of components in a compound. We calculate the formula for 100 g of compound carbon hydrogen oxygen mass 26.7 g 2.2 g 71.1 g number of moles 26.7/12 2.2/1 71.1/16 = 2.22 = 2.2 = 4.44 divide by least number of moles 2.22/2.2 = 1.00 2.2/2.2 = 1 4.44/2.2 = 2.01 numbers rounded off are- C - 1 H - 1 O - 2 empirical formula - CHO₂ mass of one empirical unit - 12 + 1 + (16x2) = 45 number of empirical units - 90/45 = 2 Therefore molecular formula - 2(CHO₂) Molecular formula - C₂H₂O₄