The same 12.04 g sample holds 1.85 g of hydrogen and 2.85 g of nitrogen. What is the mass percentage of nitrogen?

1. Divide the nitrogen mass by the total sample mass: 2.85 g / 12.04 g. 2. Multiplying by 100 percent gives 23.7 percent nitrogen. 3. The value 15.4 percent belongs to hydrogen, from 1.85 g / 12.04 g. 4. The value 61.0 percent belongs to carbon, so check which mass the question names. 5. The three percentages 61.0, 15.4 and 23.7 add to about 100 percent, which is a useful sanity check. _Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.2 Determining Empirical and Molecular Formulas_