Ozone

=Ozone = Ozone is otherwise known as trioxygen, or O 3 . It exists as an allotrope. It exists naturally in Earth's atmosphere in small concentrations of about three molecules of ozone for every 10 million molecules of air, and is also useful in many industrial applications.

Navigation

 * =====History=====
 * Structure and Chemical Properties
 * Ozone in the Atmosphere
 * Ozone in the Stratosphere
 * Ozone in the Troposphere
 * Ozone Depletion
 * Ozone in Industrial Applications
 * Additional Resources

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Ozone was first detected by Christian Fredrich Schönbeinafter a lightenining storm. He called the smell he sensed during lightning storms ozein, which was derived from the Greek word "to smell." The formula for ozone was determined by another scientist, Jacques-Louis Soret in 1865, and was confirmed bySchönbein in 1867.=====

==Structure and Chemical Properties == Ozone is a molecule that exists in a gaseous state at room temperature and has a slightly blue color to it. Ozone condenses to a blue liquid at -112 degrees Celsius, as well as it it forms a solid at -193 degrees celsius. The density of ozone is 2.141 kg/m3.

Ozone, or O 3 , is comprised of three oxygen atoms. Two of the oxygen atoms participate in a double bond, and the third is bonded to the O 2 pair singly. This contributes to the bent shape found in O 3 , with a central angle of 116.78 degrees. Because one end of the O 3 molecule is slightly positive and the other end is slightly negative, ozone molecules are polar molecules, as well. Furthermore, one molecule of ozone has a molar mass of 48 g/mol. The odor of ozone is distinct, and can often be detected in amounts as small as 0.01μmol/mol. Its odor is characterized as similar to chlorine bleach. Ozone only dissolves partially in water, though the molecule itself is highly reactive.

Refractive Index: 1.2226 (liquid) Coordination Geometry: diagonal

Ozone in the Atmosphere
Ozone is an important molecule associated with Earth's greenhouse effect. Essentially, ozone is good when it is located in the upper atmosphere and bad when it is located in the lower atmosphere.

===<span style="font-family: Arial,Helvetica,sans-serif;">Ozone in the Stratosphere === <span style="font-family: Arial,Helvetica,sans-serif;">The stratosphere is the layer of the atmosphere located between 10 and 50 km above the surface of the earth. This is the area where the presence of ozone is most abundant. Ozone in this region acts as an important greenhouse gas, and is responsible for filtering out rays of UV light that are shorter than 320 nm. This helps to protect life on earth from harmful UV rays as well as to help regulate the temperature on Earth. <span style="font-family: Arial,Helvetica,sans-serif;">Ozone is formed in the stratosphere as O 2 <span style="font-family: Arial,Helvetica,sans-serif;">molecules react with UV light rays to form O 3 <span style="font-family: Arial,Helvetica,sans-serif;">. More specifically:
 * 1) <span style="font-family: Arial,Helvetica,sans-serif;">O 2 <span style="font-family: Arial,Helvetica,sans-serif;">+ photon → 2O
 * 2) <span style="font-family: Arial,Helvetica,sans-serif;">O + O 2 <span style="font-family: Arial,Helvetica,sans-serif;">→ O 3

<span style="font-family: Arial,Helvetica,sans-serif;">O <span style="font-family: Arial,Helvetica,sans-serif; font-size: 70%;">3 <span style="font-family: Arial,Helvetica,sans-serif;"> is subsequently destroyed destroyed by as it meets O <span style="font-family: Arial,Helvetica,sans-serif; font-size: 70%;">2 <span style="font-family: Arial,Helvetica,sans-serif;"> gas in this fasion: <span style="font-family: Arial,Helvetica,sans-serif;">This process of creating and almost simultaneously destroying ozone molecules is the basis of the [|Chapman Cycle], which was name coined in 1930 by scientist Sydney Chapman. Beside characterizing the chemistry associated with this the degeneration and regeneration of ozone, Chapman also determined that the sun burns away approximately 12% of the ozone layer on a daily basis.
 * <span style="font-family: Arial,Helvetica,sans-serif;">O 3 <span style="font-family: Arial,Helvetica,sans-serif;">+ O → O 2

===<span style="font-family: Arial,Helvetica,sans-serif;">Ozone in the Troposphere === <span style="font-family: Arial,Helvetica,sans-serif;">The[| troposphere]is the section of the atmosphere located between 12 and 20 km above the Earth's surface, and is the location where ozone concentration is considered problematic. A majority of the ozone at this level fo the atmosphere is formed by the reactions between UV light rays and pollutants such as Nitrogen Oxides (NOx), Sulfur Oxides (SOx), and Volatile Organic Compounds (VOCs). In the case of NOx, NO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 70%;">2 <span style="font-family: Arial,Helvetica,sans-serif;"> specifically, the creation of ozone occurs as UV light disassociates NO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 70%;">2 <span style="font-family: Arial,Helvetica,sans-serif;"> into Nitrogen Oxide and Oxygen. The effects can be seen more readily in this format: <span style="font-family: Arial,Helvetica,sans-serif;">VOCs also carry the potential to contribute to the creation of ozone in the troposphere. VOCs originate from both natural and artificial means. Naturally, VOCs come from some plants and bacterias. VOCs are also created through the combustion of gasoline and other chemicals such as nailpolish remover. VOCs react with sunlight and NOx in the troposphere to create ozone and a variety of other products. As such: <span style="font-family: Arial,Helvetica,sans-serif;">Lastly, SOx can also react with ozone to create disastrous compounds, as well. Among other possibilities, SOx in the form of SO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 70%;">2 <span style="font-family: Arial,Helvetica,sans-serif;"> can react with water and ozone to create sulfuric acid. SO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 70%;">2 <span style="font-family: Arial,Helvetica,sans-serif;"> is common derived from burning sulfur-rich coal. This looks like: <span style="font-family: Arial,Helvetica,sans-serif;">The accumulation of ozone and these other pollutants at such a low level of the atmosphere have the effects of creating smog clouds lower to the ground, as well as aggrivating health conditions such as:
 * 1) <span style="font-family: Arial,Helvetica,sans-serif;">NO 2 <span style="font-family: Arial,Helvetica,sans-serif;">+ sunlight → NO + O
 * 2) <span style="font-family: Arial,Helvetica,sans-serif;">O + O 2 <span style="font-family: Arial,Helvetica,sans-serif;">→ O 3
 * <span style="font-family: Arial,Helvetica,sans-serif;">VOCs + NOx + sunlight → O 3 <span style="font-family: Arial,Helvetica,sans-serif;">+ other products
 * <span style="font-family: Arial,Helvetica,sans-serif;">3SO 2 <span style="font-family: Arial,Helvetica,sans-serif;">+ 3H 2 <span style="font-family: Arial,Helvetica,sans-serif;">O + O 3<span style="font-family: Arial,Helvetica,sans-serif;">→ 3H 2 <span style="font-family: Arial,Helvetica,sans-serif;">SO 4
 * <span style="font-family: Arial,Helvetica,sans-serif;">Respiratory irritation and infection
 * <span style="font-family: Arial,Helvetica,sans-serif;">Asthma and bronchitis
 * <span style="font-family: Arial,Helvetica,sans-serif;">Reduced lung function, which makes breathing more difficult
 * <span style="font-family: Arial,Helvetica,sans-serif;">Scarring of lung tissue caused by repeated swelling and regeneration of the layer

===<span style="font-family: Arial,Helvetica,sans-serif;"><span style="font-family: Arial,Helvetica,sans-serif;"> Ozone Depletion === <span style="font-family: Arial,Helvetica,sans-serif;">Ozone depletion is referring to a decrease in the volume of the ozone layer since 1970, as well as longer springtime decreases in ozone concentration in a particular place known as the ozone hole. This decrease is typically measured in Dobon Units, which is the concentration in 1 square centimeter columns extending from the earth's surface up to the edge of the atmosphere. Dobson Units are used rather than in ppm as ozone concentration is only 3 or 4 ppm. Ozone layer depletion has been primarily confirmed through use of the [|Total Ozome Mapping Spectrometer] (TOMS).

<span style="font-family: Arial,Helvetica,sans-serif;">Ozone depletion has been largely attributed to a group of compounds known as chloroflourocarbons (CFCs). CFCs were invented in the mid-1920's and became commonly used in the 1930's in refrigeration, aerosols, and air conditions. This was considered a breakthrough because CFCs were inert, seemingly safe compounds that helped improve the quality of life for virtually all families in the United States. However, as CFCs were released into the atmosphere, its inert properties became problematic as the CFC molecules remained in the atmosphere for long periods of time. In 1973, scientists discovered that the chlorine in CFCs were linked to ozone depletion. The 1980's brought legislation such as the Montreal Protol which banned the production of CFCs and other ozone-depleting chemicals. This has helped to restore the ozone layer and subsequently protect human life from harmful UV rays from the sun.

<span style="font-family: Arial,Helvetica,sans-serif;">Ozone in Industrial Applications
<span style="font-family: Arial,Helvetica,sans-serif;">In industrial applications, the most common uses of ozone include the production of pharmaceuticals, lubricans, and in other productions where breaking bonds between carbon are necessary. Ozone is also commonly used in water filtration as an alternative to chlorine disinfection of water sources as it is considered less toxic and it requires a smaller concentration in order to kill many water-borne micro-organisms. <span style="font-family: Arial,Helvetica,sans-serif;">Ozone also has small applications in agriculture when it is used to treat freshly-cut pineapple and banana. The purpose of this is to increase the flavoid count. While this process has also been shown to decrease the concentration of ascorbic acid, the net gain from flavoid count is greater. <span style="font-family: Arial,Helvetica,sans-serif;">Other industrial uses of ozone include:
 * <span style="font-family: Arial,Helvetica,sans-serif;">Disinfection of laundry in hospital facilities
 * <span style="font-family: Arial,Helvetica,sans-serif;">Deoderize air and objects after fires
 * <span style="font-family: Arial,Helvetica,sans-serif;">Kill bacteria on foods and other surfaces
 * <span style="font-family: Arial,Helvetica,sans-serif;">Sanitize swimming pools
 * <span style="font-family: Arial,Helvetica,sans-serif;">Clean and bleach fabric

Additional Information

 * Ozone - Wikipedia
 * Chemistry in the Sunlight - NASA
 * [|Ozone Basic Information - EPA]
 * Ozone - JMOL

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