What is the number of moles of nitrogen atoms present in one mole of cytosine?

Which has the maximum number of molecules?

How many $g$ of $H_2SO_4$ are present in $0.25 \, \text{mol}$ of $H_2SO_4$?

Avogadro number is

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

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 $STP$.