How can the empirical formula of a compound be experimentally found?

1 Answer
Jun 1, 2016

By burning a known mass.


Microanalysis of organic compounds typically takes an accurate mass of unknown compound and burns it under controlled conditions. So if you take the generic #C_nH_mO_p#, and burns it, you get the combustion products, #CO_2#, and water.

The combustion products are shunted to a gas chromatograph, where their percentage composition may be very accurately measured. The result is a percentage BY MASS of #C# and #H#, and (in a separate experiment depending on the analyzer) #N#. There should be other answers on these boards that go into more detail.

For compounds containing metals, or other elements, there are other means to determine the elemental composition.