1)
Lets take 100g of this compound.
It contains
50.05 g S and 49.95 g O.
2)
M(S) = 32.06 g/mol
M(O) = 16.00 g/mol
50.05 g S*1mol S/32.06 g S= 1.56 mol S
49.95 g O*1mol O/16.00 g O =3.12 mol O
3) S:O =
=1.56 mol S : 3.12 mol O = (1.56 mol /1.56 mol ) : (3.12 mol /1.56 mol) =1:2
(mol S):(mol O)=1 : 2
SO2