The number of water molecules in $1 \, L$ of water is = ............

From $44 \ mg$ of $CO_2$,$2 \times 10^{20}$ molecules of $CO_2$ are removed. The number of molecules of $CO_2$ left are (Given $N_A = 6 \times 10^{23}$):-

The mass of one hydrogen atom is of the order of

$K-40$ is a natural radioactive isotope which constitutes $0.012\%$ of natural potassium. If a cup of milk contains $370 \ mg$ of $K$,how many atoms of $K-40$ are ingested?

Find the number of moles of sodium atoms in $6.9 \times 10^{-2} \ kg$ (Atomic mass $= 23 \ g \ mol^{-1}$)

The largest number of molecules is in