What are the empirical and molecular formulae of an organic species, whose percentage composition is: #C:38.7%;H:9.7%;O,51.6%#? A #0.93*g# mass of this material occupies #0.336*L# at #"STP"#.
We get, eventually,
As with all these problems, we assume a mass of
(Note that an analyst normally does not give you
And now we divide thru by the smallest atomic quantity to get an empirical formula of
And now we use the gas data to estimate a molecular mass. The molar volume an Ideal Gas at
And thus the molar mass of our vapour is
Now it is FACT, the molecular formula is ALWAYS a whole number multiple of the empirical formula, i.e.
We solves for