The empirical formula of a compound is $C_2H_5O$ and its molecular weight is $90$. The molecular formula of the compound is:

Complete combustion of a hydrocarbon yields $0.72 \ g$ of water and $3.08 \ g$ of $CO_2$. What is the empirical formula of the hydrocarbon?

In a compound made of $X$ and $Y$,their masses are equal. If the atomic masses of $X$ and $Y$ are $30$ and $20$ respectively,then the molecular formula of the compound will be ......... (Its molecular mass $= 120$).

$A$ compound of carbon,hydrogen,and nitrogen contains three elements in the respective ratio of $9 : 1 : 3.5$ grams. The empirical formula for the compound is

The molecular formula of a compound is $X_4O_6$. If $10 \ g$ of the compound contains $5.62 \ g$ of $X$,what is the approximate atomic mass of $X$ in $amu$?

$120 \ g$ of an organic compound that contains only carbon and hydrogen gives $330 \ g$ of $CO_{2}$ and $270 \ g$ of water on complete combustion. The percentage of carbon and hydrogen,respectively,are ...... .