Question

An atom of some element X weighs $6.644\times {10}^{-23}$. Calculate the number of gram-atoms in $40$ Kg of it.

Answer 1

Mass of $1$ atm $\times N_A$ $=1$ mol of atoms of $X$

$1$ mol of $X$ $=6.644\times {10}^{23}\times 6.022\times {10}^8$

$=40g$

No of gram atoms $=\frac{40\times 1000}{40}=1000$