The mass of a sample of aluminum is $54 \ g$. The mass of the same number of magnesium atoms will be ......... $g$.

If Avogadro number $N_A$ is changed from $6.022 \times 10^{23} \ mol^{-1}$ to $6.022 \times 10^{20} \ mol^{-1},$ this would change

The number of water molecules present in a drop of water weighing $0.018 \ g$ is

Volume of a gas at $STP$ is $1.12 \times 10^{-7} \ cc$. Calculate the number of molecules in it.

The atomic weights of two elements $A$ and $B$ are $40$ and $80$ respectively. If $x \ g$ of $A$ contains $y$ atoms,how many atoms are present in $2x \ g$ of $B$?

The system that contains the maximum number of atoms is