A 230 g sample of a compound contains 136.6 g of carbon, 26.4 g of hydrogen, and 31.8 g of nitrogen. The rest is oxygen. What is the mass percent of oxygen in the compound? 11.48%
If the total amount of the sample is 230g and they give each component of the sample, we add the given amount of grams of each element and subtract the given from 230g.