Question

How many atoms are contained in $23g$ of sodium? ($Na=23u$)

Answer 1

Given that,

Mass of the $Na$ atom (W) = $23$ gm

Molar mass of $Na$ (M) = $23$ gm/mol

$\therefore$ Number of moles (n) = $\frac{W}{M}=\frac{23}{23}=1$ mol

$\therefore$ Number of $Na$ atoms = $n\times N_A=1\times 6.022\times {10}^{23}=6.022\times {10}^{23}$ atoms