Information AboutOzone |
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! | Ozone |- | align="center" colspan="2" | |- ! | General |- | Systematic Name | Trioxygen |- | Molecular Formula | O3 |- | Molar Mass | 47.998 g/mol |- | Appearance | bluish colored gas |- | CAS Number | {Link without Title} |- ! | Properties |- | Density and Phase | 2.144 g/l (0 °C), gas |- | Solubility in Water | 0.105 g/100 ml (0 °C) |- | Melting Point | 75.95 K, −197.2 °C |- | Boiling Point | 161.25 K, −111.9 °C |- ! | Thermodynamic data |- | [[Standard enthalpy change of formation|Standard enthalpy of formation]] Δf''H''°solid | +142.3 kJ/mol |- | Standard Molar Entropy ''S''°solid | 237.7 J.K−1.mol−1 |- ! | Hazards |- | EU Classification | not listed |- | NFPA 704 | |- ! | Supplementary Data Page |- | Structure And properties | ''n'' , ''εr'' , etc. |- | Thermodynamic data | Phase behaviour Solid, liquid, gas |- | Spectral Data | UV , IR , NMR , MS |- | Regulatory Data | Flash Point , RTECS Number , etc. |- | | Except where noted otherwise, data are given for materials in their |- |} ''For other uses, see Ozone (disambiguation) .'' Ozone (O3) is an Allotrope of Oxygen , the Molecule consisting of three oxygen Atom s, a triatomic molecule, instead of the more stable diatomic O2. Ozone is a pale blue Gas at Standard Temperature And Pressure . It forms a dark blue Liquid below −112 °C and a dark blue Solid below −193 °C. Ozone is a powerful Oxidizing agent. It is also unstable, decaying to ordinary oxygen through the reaction: :2 O3 → 3 O2 This reaction proceeds more rapidly with increasing temperature and decreasing pressure. It is present in low concentrations throughout the with harmful effects on Lung function and in the upper atmosphere it prevents damaging Ultraviolet light from reaching the Earth's surface. It is also formed from O2 by electrical discharges such as Lightning , and by action of high energy Electromagnetic Radiation . Some kinds of electrical equipment generate significant levels of ozone. This is especially true of devices using High Voltage s, such as Television sets, Laser Printer s, and Photocopier s. Electric motors using Brush es can generate ozone from repeated Spark ing inside the unit. Large motors, such as those used by elevators or hydraulic pumps, will generate more ozone than smaller motors. Discovery of ozone Ozone was discovered by Christian Friedrich Schönbein in 1840 , who named it after the Greek word for smell (''ozein''), from the peculiar odor in lightning storms. The odor from a lightning strike is from electrons freed during the rapid chemical changes, not the ozone itself [http://gcmd.gsfc.nasa.gov/Resources/FAQs/ozone.html . Sax's Dangerous Properties of Industrial Materials, 8th. ed. indicates that ozone is colorless (perhaps pale blue) in gas but dark blue as a liquid. In concentrations of 0.015ppm, ozone has a barely detectable odor. At 1 ppm it has a sulfur-like odor. However the smell is also attributed to the discharge of the electrical current from the dipole bonding and reformation of the oxygen model, which at high temperatures is known to release an inert odor. Ozone in Earth's atmosphere satellite.]] Ozone layer ''See main article: Ozone Layer .'' The highest levels of ozone in the atmosphere are in the Stratosphere , in a region also known as the Ozone Layer . Here it filters out the shorter wavelengths (less than 320 nm) of Ultraviolet light (270 to 400 nm) from the Sun that would be harmful to most forms of Life in large doses. These same wavelengths are also responsible for the production of Vitamin D , which is essential for human health. The standard way to express total ozone amounts in the atmosphere is by using Dobson Unit s. Ozone used in industry is measured in Ppm ( OSHA exposure limits for example), and percent by mass or weight. Air pollution ''See main articles: Tropospheric Ozone and Air Pollution .'' Ozone is not directly emitted by car engines or by industrial operations themselves. These sources emit Hydrocarbon s and Nitrogen Oxide s that react with sunlight to form ozone directly at the source of the pollution being emitted and in the atmosphere's boundary layer (1 to 3 km altitude). The mix of hydrocarbons, nitrogen oxides, and ozone are the major components of smog that frequently occurs in urban and suburban areas. Recent satellite maps of Nitrogen Dioxide (NO2) clearly show the worldwide distribution of polluted regions associated with industrial activity (automobiles, factories, and fossil fuel power generation). There is a great deal of evidence to show that ozone at the earth's surface can harm lung function and irritate the respiratory system (WHO Europe reports, cited below). Ozone has been found to convert Cholesterol in the blood stream to plaque (which causes hardening and narrowing of arteries). This cholesterol product has also been implicated in Alzheimer's Disease , suggesting a link between the inflammatory response associated with head injury and Alzheimer's. Air quality guidelines such as those from the World Health Organization are based on detailed studies of what levels can cause measurable health effects. Although ozone was present at ground level before the industrial revolution, peak concentrations are far higher than the pre-industrial levels and even background concentrations well away from sources of pollution are substantially higher [http://www.grida.no/climate/ipcc_tar/wg1/142.htm . Ozone reacts directly with some hydrocarbons such as Aldehyde s and thus begins their removal from the air, but the products of ozonolysis are themselves key components of Smog . Ozone Photolysis by UV light leads to production of the Hydroxyl Radical and this plays a part in the removal of hydrocarbons from the air, but is again a step in the creation of components of smog such as Peroxyacyl Nitrates which are powerful eye irritants. Ultimately, ozone is one component of smog which is harmful in itself and contributes both to the production and ultimate removal of other air pollutants. Industrial production Industrially, ozone is produced with short reactions taking place are: :3H2O → O3 + 6H+ + 6e− ΔEo = − 1.53 V :6H+ + 6e− → 3H2 ΔEo = 0 V :2H2O → O2 + 4H+ + 4e− ΔEo = −1. 23 V So that in the net reaction three equivalents of water are converted into one equivalent of ozone and one equivalent of Hydrogen . Oxygen formation is a competing reaction... Reactions Ozone will oxidize metals (except Gold , Platinum , and Iridium ) to Oxides of the metals in their highest Oxidation State : :2 Co2+ + 2 H+ + O3 → 2 Co3+ + H2O + O2 Ozone oxidizes oxides to Peroxides . It also oxidizes oxides to oxides of higher oxidation number: :SO2 + O3 → SO3 + O2 :NO + O3 → NO2 + O2 The above reaction is accompanied by Chemiluminescence . The NO2 can be further oxidized: :NO2 + O3 → NO3 + O2 The NO3 formed can react with NO2 to form N2O5: :NO2 + NO3 → N2O5 Ozone reacts with Carbon to form Carbon Dioxide , even at room temperature: :C + 2 O3 → CO2 + 2 O2 Ozone does not react with ammonium Salts but it reacts with Ammonia to form Ammonium Nitrate : :NH3 + 4 O3 → NH4NO3 + 4 O3 + H20 Ozone reacts with Sulfides to make Sulfates : :PbS + 4 O3 → PbSO4 + 4 O2 Sulfuric Acid can be produced from ozone, either starting from elemental Sulfur or from Sulfur Dioxide : :S + H2O + O3 → H2SO4 :3 SO2 + 3 H2O + O3 → 3 H2SO4 All three Atoms of ozone may also react, as in the reaction with Tin (II) chloride and Hydrochloric Acid : :3 SnCl2 + 6 HCl + O3 → 3 SnCl4 + 3 H2O In the Gas Phase , ozone reats with Hydrogen Sulfide to form sulfur dioxide: :H2S + O3 → SO2 + H2O In an Aqueous solution, however, two competing simultaneous reactions occur, one to produce elemental sulfur, and one to produce sulfuric acid: :H2S + O3 → S + O2 + H2O :3 H2S + 4 O3 → 3 H2SO4 Iodine Perchlorate can be made by treating iodine dissolved in cold Anhydrous Perchloric Acid with ozone: :I2 + 6 HClO4 + O3 → 2 I(ClO4)3 + 3 H2O Solid Nitryl perchlorate can be made from NO2, ClO2, and O3 gases: :2 NO2 + 2 ClO2 2 O3 → 2 NO2ClO4 + O2 Ozone can be used for Combustion reactions and combusting gases in ozone provides higher temperatures than combusting in Dioxygen (O2). Following is a reaction for the combustion of carbon subnitride: :3 C4N2 + 4 O3 → 12 CO + 3 N2 Ozone can react at cryogenic temperatures. At 77 K (-196 °C), atomic Hydrogen reacts with liquid ozone to form a hydrogen Superoxide Radical , which dimerizesHorvath M., Bilitzky L., & Huttner J., 1985. "Ozone." pg 44-49: :H + O3 → HO2 + O :2 HO2 → H2O4 Ozonides can be formed, which contain the Ozonide anion, O3-. These compounds are explosive and must be stored at cryogenic temperatures. Ozonides for all the alkali metals are known. KO3, RbO3, and CsO3 can be prepared from their respective superoxides: :KO2 + O3 → KO3 + O2 Although KO3 can be formed as above, it can also be formed from [[potassium hydroxide]] and ozoneHousecroft & Sharpe, 2005. "Inorganic Chemistry." pg 439: :2 KOH + 5 O3 → 2 KO3 + 5 O2 + H2O NaO3 and LiO3 must be prepared by action of CsO3 in liquid NH3 on an ion exchange resin containing Na+ or Li+ ionsHousecroft & Sharpe, 2005. "Inorganic Chemistry." pg 265: :CsO3 + Na+ → Cs+ + NaO3 Treatment with ozone of Calcium dissolved in ammonia leads to ammonium ozonide and not calcium ozonideHorvath M., Bilitzky L., & Huttner J., 1985. "Ozone." pg 44-49: :3 Ca + 10 NH3 + 6 O3 → Ca•6NH3 + Ca(OH)2 + Ca(NO3)2 + 2 NH4O3 + 2 O2 + H2 Ozone can be used to remove Manganese from the Water , forming a Precipitate which can be filtered: :2 Mn2+ + 2 O3 + 4 H2O → 2 MnO(OH)2 (s) + 2 O2 + 4 H+ Ozone will also turn Cyanides to the one thousand times less toxic Cyanates : :CN- + O3 → CNO- + O2 Finally, ozone will also completely decompose Urea Horvath M., Bilitzky L., & Huttner J., 1985. "Ozone." pg 259, 269-270: :(NH2)2CO + O3 → N2 + CO2 + 2 H2O Use in industry Ozone can be used for Bleach ing substances and for killing bacteria. Many municipal drinking water systems kill bacteria with ozone instead of the more common Chlorine . Ozone does not form Organochlorine compounds, but it also does not remain in the water after treatment, so some systems introduce a small amount of chlorine to prevent bacterial growth in the pipes, or may use chlorine intermittently, based on results of periodic testing. Where electrical power is abundant, ozone is a cost-effective method of treating water, as it is produced on demand and does not require transportation and storage of hazardous chemicals. Once it has decayed, it leaves no taste or odor in drinking water. Industrially, ozone or ozonated water is used to:
Ozone is a reagent in many Organic Reactions in the laboratory and in industry. Ozonolysis is the cleavage of an Alkene to Carbonyl compounds. Use in medicine Ozone, along with Hypochlorite ions, is naturally produced by White Blood Cell s and the roots of Marigold s as a means of destroying foreign bodies. When ozone breaks down it gives rise to oxygen Free Radical s, which are highly reactive and damage or destroy most organic molecules. Ozone has a number of medical uses. It can be used to affect the body's Antioxidant -prooxidant balance, since the body usually reacts to its presence by producing antioxidant enzymes. Many hospitals in the U.S. and around the world use large ozone generators to decontaminate operating rooms between surgeries. The rooms are cleaned and then sealed airtight before being filled with ozone which effectively kills or neutralizes all remaining bacteria. Ozone Therapy has blossomed into a thriving field of Alternative Medicine , and there are a host of claimed applications above and beyond what has actually been verified by studies. In the United States ozone therapy is illegal, as the Food And Drug Administration (FDA) has not approved its use on humans. Medical ozone therapy is recognized in Bulgaria, Cuba, Czech Republic, France, Germany, Israel, Italy, Mexico, Romania and Russia. It is currently used legally in 16 Nations. At least 12 states in the USA (AK, AZ, CO, GA, MN, NY, NC, OH, OK, OR, SC and WA) have passed legislation to ensure that alternative therapies are available to consumers. Physicians in those states can legally use ozone as an alternative treatment in their practice without fear of prosecution. At least one death has been attributed to application of ozone through in the U.S. "Air cleaners" which produce "activated oxygen", i.e., ozone, are often sold in the U.S. nonetheless. See Air Ioniser . Other uses During the 1992 U.S. Presidential Election , George H.W. Bush referred to his opponents Bill Clinton and Al Gore as " Bozo and Ozone", respectively, the latter in connection with Gore's well known stance on environmental issues. Ozone is also popularly used in spas or hot tubs instead of Chlorine or Bromine for keeping the water free of bacteria. Ozone gas is created by an ultraviolet light bulb or corona discharge chip and injected into the plumbing system. See also
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