The total number of gm-molecules of $SO_2Cl_2$ in $13.5 \ g$ of sulphuryl chloride is

$7.0 \, g$ of $N_2$,$8.0 \, g$ of $O_2$,and $34.0 \, g$ of $NH_3$ are present in a $1 \, L$ vessel. The active masses in $mol \, L^{-1}$ are respectively:

What is the number of moles present in $1 \ m^3$ of any gas at $STP$?

What is the value of Avogadro's number?

The number of oxygen atoms in $4.4 \ g$ of $CO_2$ is approximately ........ $\times 10^{23}$.

How many $H$ atoms are present in $0.046 \ g$ of ethanol $(C_2H_5OH)$?