80 g of oxygen contains as many atoms as in

No. of mole of oxygen = $\frac{80}{16}$ = 5 moles
1 mole contains avogadro no. of atom i.e., 6.02 x 10²³  atoms.
$\therefore$ 5 moles contain 6.02 x 10²³ x 5 atoms
= 30.1 x 10²³ atoms
No. of moles of hydrogen = $\frac{5}{1}$= 5 moles
5 moles of hydrogen contains 30.1 x 10²³ atoms.