Why do empirical formulas exist?

1 Answer
Jun 23, 2018

Answer:

So educators have something to ask students....

Explanation:

The empirical formula is the simplest whole number ratio defining the ratio of constituent atoms in a species. And it is approached by experiment...that is what #"empirical"# means, #"by experiment"#. And given an unknown compound, usually an organic compound of the form, #C_xH_yN_zO#...the compound can be COMBUSTED in a furnace, and the product gases, #CO_2#, #H_2O#, and #NO_2# are shunted to a gas chromatograph, where their percentage composition may be measured very accurately.

Given such analysis, the molecular formula is some multiple of the empirical formula. The student or analyst must make SOME determination of the molecular mass ..... and …… #"molecular formula"-=nxx"empirical formula"#. Of course #n# MAY be equal to #"UNITY"#.

Such elemental analyses is ALWAYS quoted when an organic or inorganic chemist publishes a new compound. If the microanalysis is not present, then the formula of the compound is open to question...