Lab 4

• The ozone layer is a layer in Earth‘s atmosphere which contains relatively high concentrations of ozone (O3).
• Ozone (O3, trioxygen) is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope (O2).
• The ozone–oxygen cycle is the process by which ozone is continually regenerated in Earth's stratosphere, converting ultraviolet radiation (UV) into heat.

  ▪ Ozone molecules exposed to ultraviolet may break down into O2 and O releasing heat and warming the upper atmosphere.

  ▪ The free oxygen atom may then combine with an oxygen molecule, creating another ozone molecule, or it may take an oxygen atom from an existing ozone molecule to create two ordinary oxygen molecules.
• The ozone layer can be depleted by free radical catalysts, including nitric oxide (NO), nitrous oxide (N2O), hydroxyl (OH), atomic chlorine (Cl), and atomic bromine (Br).
• The breakdown of ozone in the stratosphere results in the ozone molecules being unable to absorb ultraviolet radiation.
• Ozone hole – effects on our environment

  Rise in temperature of the earth

  Destroying chlorophyll

  Destroying the plankton

  Immunosuppression animals

  Influence on the atmosphere

  Substances causing the disappearance of ozone.
• A chlorofluorocarbon (CFC) is an organic compound that contains carbon, chlorine, and fluorine, produced as a volatile derivative of methane and ethane.
• A common subclass is the hydrochlorofluorocarbons (HCFCs), which contain hydrogen, as well. They are also commonly known by the DuPont trade name Freon
• Haloalkanes ▪ a subset of the general class of halocarbons which hydrogen atoms partly or entirely were traded for atoms of halogens in (mainly of bromine)
• Nitrous oxide N2O gives rise to NO on reaction with oxygen atoms, and this NO in turn reacts with ozone. As a result, it is the main naturally occurring regulator of stratospheric ozone