Mahesh gifts a diamond ring of $0.1$ mole to Suresh on his birthday. How many grams of diamond did he gift?

If one atom of an element $X$ weighs $6.643 \times 10^{-23} \ g$,then find the number of moles of atoms in $50 \ kg$ of element $X$. (in $moles$)

The mass and volume of $1/4$ mole of oxygen gas at $STP$ are respectively .....

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

Number of atoms in the following samples of substances is largest in

One mole of carbon atom weighs $12 \; g$. The number of atoms in it is equal to: (Mass of one carbon-$12$ atom is $1.9926 \times 10^{-23} \; g$)