Calculate the number of atoms in
0.20 mole molecules of oxygen

Explanation

1 mole molecules of oxygen `=6.02 xx 10^(23)` molecules of oxygen `=2 xx 6.02 xx 10^(23)` atoms of oxygen `=12.04 xx 10^(23)` atoms of oxygen
0.20 moles molecules of oxygen `=0.20 xx 12.04 xx 10^(23)`
`=2.408 xx 10^(23)` atoms of oxygen.