# How do you find an empirical formula?

Typically, a sample is combusted and the combustion products are very accurately measured on a gas chromatograph. For an organic sample, carbon is measured as carbon dioxide; hydrogen content is measured as water; and nitrogen content is measured as $N {O}_{2}$ (in some systems, nitric oxide is reduced back to dinitrogen). Percentage hydrogen, carbon, and nitrogen content can then be used to find the empirical formula. There should be many examples of these sorts of problems on these boards.