Everything is balanced except the O. Temporarily we use a fractional coefficient in front of the O2 to give PbS + 1.5 O2 = PbO + SO2 then to get rid of the fraction multiply by 2 to give 2PbS + 3O2 = 2PbO + 2SO2 Solution Everything is balanced except the O. Temporarily we use a fractional coefficient in front of the O2 to give PbS + 1.5 O2 = PbO + SO2 then to get rid of the fraction multiply by 2 to give 2PbS + 3O2 = 2PbO + 2SO2.