Find the number of moles present in $0.448 \ L$ of dihydrogen at $STP$. (in $mol$)

Find the number of molecules,number of carbon atoms,number of hydrogen atoms,and total number of atoms in $5.6 \ L$ of $CH_4$ at $STP$.

$0.1$ mole of compound $'S'$ will weigh $.......... \ g$.
(Given molar mass in $g \ mol^{-1} \ C: 12, H: 1, O: 16$)

The number of hydrogen atoms present in $5.4 \ g$ of urea is : (Given : Molar mass of urea: $60 \ g \ mol^{-1}$, $N_{A} = 6.022 \times 10^{23} \ particles \ mol^{-1}$)

$138 \ g$ of ethyl alcohol is mixed with $72 \ g$ of water. The ratio of mole fraction of alcohol to water is

If $3.01 \times 10^{20}$ molecules are removed from $98 \ mg$ of $H_2SO_4$,then the number of moles of $H_2SO_4$ left are: