ethylene glycol is used as an automoblie antifreeze and in the manufacture of polyester fibers. the name of glycol stems from the sweet taste of this poisonous compound. combustion of 6.38mg of ethylene glycol gives 9.06mg CO2 and 5.58mg H2O. the compound contains only C H and O. what are the mass percentage of the elements in the ethylene glycol? I know that the formula is C2H6O2 (only because I looked it up). The anwser is in the back of my book, but I want to know how to solve it myself.