A sample of a compound that contains only the elements \(\ce{C}\), \(\ce{H}\), and \(\ce{N}\) is completely burned in \(\ce{O2}\) to produce \(\pu{44.0 g}\) of \(\ce{CO2}\), \(\pu{45.0 g}\) of \(\ce{H2O}\), and some \(\ce{NO2}\). A possible empirical formula of the compound is

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We can calculate the number of moles of each element produced.

$$ \pu{44.0 g }\ce{CO2} \cdot \frac{\pu{1 mol }\ce{CO2}}{\pu{44 g }\ce{CO2}} \cdot \frac{\pu{1 mol }\ce{C}}{\pu{1 mol }\ce{CO2}} = \pu{1 mol }\ce{C} $$ $$ \pu{45.0 g }\ce{H2O} \cdot \frac{\pu{1 mol }\ce{H2O}}{\pu{18 g }\ce{H2O}} \cdot \frac{\pu{2 mol }\ce{H}}{\pu{1 mol }\ce{H2O}} = \pu{5 mol }\ce{H} $$

The empirical formula must have a carbon to hydrogen ratio of 1 to 5.