compound weighing 115 g contains 68.3 g of carbon, 13.2 g of hydrogen, 15.9 g of nitrogen, and some amount of oxygen. What is the mass percent of oxygen in the compound?
The mass percent means that the mass of this element divide the total mass of the compound. The oxygen amount equals 115-68.3-13.2-15.9=17.6. The mass percent is 17.6/115*100%=15.3%.
