# The number of atoms in

Question:

The number of atoms in $8 \mathrm{~g}$ of sodium is $\mathrm{x} \times 10^{23}$.

The value of $x$ is .(Nearest integer)

[Given : $\mathrm{N}_{\mathrm{A}}=6.02 \times 10^{23} \mathrm{~mol}^{-1}$

Atomic mass of $\mathrm{Na}=23.0 \mathrm{u}]$

Solution:

No. of atoms $=\frac{8}{23} \times 6.02 \times 10^{23}=2.09 \times 10^{23}$

$\simeq 2 \times 10^{23}$

$=x \times 10^{23}$

$x=2$