Common gases Helping students learn the chemical formula of a range of common gases. Simple drag and drop exercise. Drag Chemical Formula to their names Water vapor Carbon dioxide Oxygen Ozone Nitrogen Hydrogen Methane Sulfur dioxide Ammonia Hydrogen sulfide Chlorine Helium Argon Neon Nitrogen dioxide H2O CO2 O2 O3 N2 H2 CH4 SO2 NH3 H2S Cl2 He Ar Ne NO2