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

1 Answer
anor277
Jun 1, 2016

By burning a known mass.

Explanation:

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.

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