Mass percent of carbon in aspirin

First we calculate the mass of one mole of aspirin. Molecular weight of C₉H₈O₄ is 180. Mass of 9 moles of C is 12*9 = 108 g. The mass percent of a component is defined: mass of component/total mass of sample * 100% Calculate the mass percent of carbon: 108/180*100% = 60%. ANS: 60%