Find the empirical formula from CO₂ and H₂O produced during combustion.
Combustion analysis determines the elemental composition of an organic compound by completely burning a weighed sample in excess oxygen. The carbon in the sample is converted entirely to CO₂, which is absorbed and weighed. Hydrogen becomes H₂O, also absorbed and weighed. Mass of C = mass CO₂ × (12.011 / 44.01) and mass of H = mass H₂O × (2.016 / 18.015). If the compound contains oxygen, its mass is found by difference: mass O = sample mass − mass C − mass H. Moles of each element are calculated, then divided by the smallest to get the simplest whole-number ratio — the empirical formula. This technique was pioneered by Justus von Liebig in the 1830s and remains a standard method in analytical chemistry for determining C, H, and N content (with a nitrogen trap added).