Here we have been given that the atomic mass of carbon `(C )` is `12 u` and the atomic mass of oxygen (O) is `16 u`. So, first of all we will calculate the mass of 1 mole of carbon dioxide by using these values of atomic masses. The mass of 1 mole of carbon dioxide `(CO_(2))` will be equal to its molecular mass expressed in grams. That is :
`1` mole of `CO_(2)` = Molecular mass of `CO_(2)` in grams
`=` Mass of C + Mass of `O xx 2`
`= 12 + 16 xx 2`
`= 44` grams
So, the mass of 1 mole of carbon dioxide is `44` grams.
Now, 44 g of carbon dioxide `= 1` mole
So, 22g of carbon dioxide `= 1/44 xx 22` mole
`= 1/22`
`= 0.5` mole , (or `0.5` mol)
Thus, 22 grams of carbon dioxide are equal to `0.5` mole.