Calculate the mass of the following,

$0.1$ mole of carbon dioxide.

Calculate the mass of the following,

$6.022 \times {10}^{23} \mathrm{molecules} \mathrm{of} {\mathrm{H}}_2\mathrm{O}$.

Which one of the following will have larger number of atoms? Justify your answer.

(a) 100 g of sodium (atomic mass of sodium = 23 u)
(b) 100 g of iron (atomic mass of iron = 56 u)