Calculate the mass of oxygen present in $0.1 \ mol$ of $Na_2CO_3 \cdot 10H_2O$. (in $g$)

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

At the same temperature,$10 \ dm^3$ of $N_2$ gas and $10 \ dm^3$ of gas $x$ contain the same number of molecules. What is the gas $x$?

Calculate the total number of electrons present in $1.4 \,g$ of dinitrogen gas.

$A$ mixture has $18 \ g$ of water and $414 \ g$ of ethanol. The mole fraction of water in the mixture is (assume ideal behavior of the mixture):

What is the numerical value of $\frac{N}{n}$? (Where $N$ is the number of molecules in a given gas sample and $n$ is the number of moles of the gas.)