The number of neutrons in $5 \ g$ of $D_2O$ ($D$ is $_1^2H$) are ................ $N_A$.

Find the number of molecules present in $70 \text{ g}$ of dinitrogen $(N_2)$.

What is the number of moles of oxygen atoms and the number of moles of $N$ atoms respectively present in one mole of thymine?

Which one of the following has the maximum number of atoms?

$A$ thin layer of cobalt is deposited on a plate with a total area of $0.5 \ m^2$ and a thickness of $0.005 \ cm$. How many cobalt atoms are deposited on the plate? (Density of cobalt $= 8.9 \ g \ cm^{-3}$,Atomic mass of $Co = 59 \ g \ mol^{-1}$)

The number of water molecules is maximum in