How to figure out this problem?

Find the empirical formula for a compound with the composition CxHyOz using the data


from this chemical reaction: 6. 64 g of the reactant CxHyOz undergoes combustion


producing 11. 52 g of carbon dioxide and 6. 288 g of H2O.How to figure out this problem?
Amount of carbon in 6.64 g sample (from weight of CO2 produced)


= 11.52 x 12.011/(12.011 + 2 x 15.999) = 3.144 g





Amount of hydrogen in sample (from weight of H2O produced)


= 6.288 x (2 x 1.008)/(2 x 1.008 + 15.999) = 0.704 g





Remaining weight of sample is oxygen = 6.64 - 3.144 - 0.704 = 2.792 g





So the ratio of the number of moles of each element in CxHyOz is





3.144/12.011 : 0.704/1.008 : 2.792/15.999 = 0.2618 : 0.6984 : 0.1745





Divide through by the smallest to obtain 1.500 : 4.002 : 1.000





and multiply by 2 to get integer values 鈫?C3H8O2 for the empirical formula.





(Values taken for relative atomic weights : C = 12.011, H = 1.008, O = 15.999)