an 8.925 g sample of a compound containing only, carbon, hydrogen , and oxygen gives 9.258 g of carbon dioxide and 5.351 g 0f water after complete combustion of the sample. what is the mass percentage of the sample

Hydrogenation reactions, in which h2 and an "unsaturated" organic compound combine, are used in the food, fuel, and polymer industries. in the simplest case, ethene (c2h4) and h2 form ethane (c2h6). if 140 kj is given off per mole of c2h4 reacting, how much heat (in mj) is released when 12 kg of c2h6 forms?