Chem 2.4

Global WarmingCO2 , CH4 and H2O can cause global warming. Infrared radiation is absorbed by the bonds in the molecules. This causes the bonds to vibrate.Greenhouse effect of a gas is determined by its atmospheric concentration and its ability to absorb infrared radiation

Chemists have a role in minimising climate change; Provide scientific evidence as verification Investigating solutions ; CCS , forming carbonates, storage in geological formations, storage in oceans Monitoring progress such as after Kyoto protocol

Ozone is constantly being formed and broken down in stratosphere by UVformationO2 + O -> O3 + heatremovalO3 + O + UV -> 2O2

Ozone is destroyed when it absorbs UV radiation. When it is reformed it emits this energy as heat which is less dangerous. Therefore it protects us from harmful UV.

Radicals can catalyse the break down of ozoneR + O3 -> RO + O2RO + O -> R + O2

Catalytic ConvertersIn Incomplete combustion (such as in a car engine) CO and Nitrogen oxides are formed due to lack of sufficient oxygen.Catalytic converters can remove these as they can be harmful.CO = poisonous gasNO = contributor to acid rain , respiratory irritants, formation of low-level ozoneCO and NO molecules diffuse across the converter and are adsorbed. Temporary bonds form between metal surface and gas molecules. Reaction takes place. Gas products are desorbed and diffuse away.

IR spectroscopy can identify pollutants in the air and the concentrations of them to monitor air pollution

Green Chemistry