In a compound,the ratio of masses of $H, C, O,$ and $N$ is $1:3:4:7$. The empirical formula is

An organic compound contains $C = 38.8\%$,$H = 16\%$ and $N = 45.2\%$. The empirical formula of the compound is:

On complete combustion of $0.492 \ g$ of an organic compound containing $C, H$ and $O$,$0.7938 \ g$ of $CO_2$ and $0.4428 \ g$ of $H_2O$ were produced. The percentage composition of oxygen in the compound is $........$

Reduction of $7.2 \, g$ of a metal oxide yields $6.4 \, g$ of the metal. If the atomic mass of the metal is $128 \, g/mol$,the formula of the oxide is .....

$64 \, g$ of an organic compound contains $24 \, g$ of carbon,$8 \, g$ of hydrogen,and the rest oxygen. The empirical formula of the compound is

What is the percentage composition of $C$ in methanoic anhydride?