A compound of carbon, hydrogen, and nitrogen contains the three elements in the respective ratio of `9 : 1 : 3.5` Calculculate the empirical formula. If the molecular weight of the compound is 108, what its molecular formula?

Explanation

As the provided ratio is by mass so let us convert the masses into atoms and establish the ratio by atoms as `(9)/(12):(1)/(1):(7)/(2xx14)=(3)/(4):(1)/(1):(1)/(4)=3:4:1`. So the empirical formula of the compound will be `C_(3)H_(4)N_(1)` which has an empirical mass value of 54g/mole. As the molecular mass is given to be 108g/mole so, the value of `n=("Molecular Mass")/("Empirical Mass")=(108)/(54)=2.`
So, molecular formula = Empirical formula `xxn` that is `(C_(3)H_(4)N_(1))_(2)=C_(6)H_(8)N_(2).`