CO2 = 1x12+2x16= 44 g/mol
SO2 = 1x32+2x16= 64 g/mol
SO3 = 1x32+3x16= 80 g/mol
NH3 = 1x14+1x3= 17 g/mol
NO2 = 1x14+2x16= 46 g/mol
N2O5 = 2x14+5x16= 108 g/mol
P2O5 = 2x31+5x16= 142 g/mol