Combustion Analysis
A technique that determines the empirical formula of an organic compound by burning it completely and weighing the CO₂ and H₂O produced.
Formula / equation
C → CO₂, H → H₂O
Unit
g
In depth
All carbon in the sample ends up in carbon dioxide and all hydrogen in water, so weighing the absorbents that trap each gas gives the mass of C and H directly. Any oxygen present is found by difference from the original sample mass, and separate methods handle nitrogen and halogens.
Examples in the real world
Burning 0.250 g of a compound to give 0.374 g CO₂ and 0.153 g H₂O identifies it as CH₄O.