On reduction with hydrogen,$3.6 \ g$ of an oxide of metal $(M)$ left $3.2 \ g$ of the metal. If the atomic weight of the metal is $64$,the formula of the oxide is:

Calculate the mass percent of different elements present in sodium sulphate $(Na_{2}SO_{4})$.

An organic compound containing carbon and hydrogen has an empirical formula of $CH_2$. The mass of $1 \ L$ of this organic gas is equal to the mass of $1 \ L$ of $N_2$ gas at the same temperature and pressure. What is the molecular formula of the organic gas?

Define empirical formula and molecular formula.

The percentage composition of carbon by mole in methane is ........... $ \% $

Complete combustion of $750 \ g$ of an organic compound provides $420 \ g$ of $CO_2$ and $210 \ g$ of $H_2O$. The percentage composition of carbon and hydrogen in the organic compound is $15.3$ and ............. respectively. (Round off to the Nearest Integer)