Ultraviolet radiation ozone

We begin our exploration of delocalized bonds with ozone, O3. As described in Chapter 7, ozone in the upper stratosphere protects plants and animals from hazardous ultraviolet radiation. Ozone has 18 valence electrons and a Lewis stmcture that appears in Figure 10-36a. Experimental measurements show that ozone is a bent molecule with a bond angle of 118°. 

Glaze, W.H. Kang, J.W. Chapin, D.H. The chemistry of water treatment processes involving ozone, hydrogen peroxide and ultraviolet radiation. Ozone Sci. Engrg. 1987, 9 (4), 335. 

This synthesis of ozone is of great benefit to life on Earth because if the ultraviolet radiation absorbed in the reaction were to reach Earths surface, it would cause immediate harm to living tissue. When it absorbs ultraviolet radiation, ozone fragments into molecular oxygen and atomic oxygen. These molecules eventually re-form ozone. Because chemical bonds are created when ozone reforms, heat energy is released ... 

Glaze W H, Kang J-W (1987) The Chemistry of Water Treatment Processes involving Ozone, Hydrogen Peroxide and Ultraviolet Radiation, Ozone Science Engineering 9 335-352. 

In recent years, there has been considerable concern over reductions in stratospheric ozone concentrations resulting from human activities. Since stratospheric ozone is the primary screen of solar ultraviolet radiation, ozone reduction would increase ultraviolet radiation (UV-B, wavelengths between 280 and 320 nm) reaching the earth s surface. 

Another factor in oxidative degradation is ultraviolet radiation, of which sunlight is a rich source. The oxidation of parylene appears to be enhanced by ultraviolet radiation. Ozone may play a mechanistic role in the ambient temperature exposure of parylenes to ultraviolet radiation in the presence of oxygen. For the best physical endurance, exposure of the parylenes to ultraviolet light must be minimized. 

Takahashi N. Ozonation of several organic compounds having low molecular weight under ultraviolet radiation. Ozone Sci Eng 1990 12 1-18. 

Ozone, produced in the stratosphere by the action of ultraviolet light on 02, helps shield the surface of the earth from harmful ultraviolet radiation. Ozone is slowly decomposed by reaction with oxygen atoms according to the following equation ... 

Above the troposphere, temperatures increase with altitude, reaching a maximum of nearly 2°C at about 50 km. This region of the atmosphere is called the stratosphere. The stratosphere contains a layer of ozone, a gas that helps shield Earth s surface from the Sun s harmful ultraviolet radiation. Ozone protects Earth by absorbing solar radiation, which raises the temperature of the stratosphere in the process. You read about the ozone layer in Chapter 1 as you began your study of chemistry. 

J.J. Cullen, P.J. Neale (1994). Ultraviolet radiation, ozone depletion, and marine photosynthesis. Photosyn. Res., 39, 303-320. 

Alternative water disinfection techniques use chlorine dioxide, ultraviolet radiation, ozone and ultrafiltration. Normally these techniques form less hazardous by-products, but the technologies are more complex and the total costs are higher. Little is known about the nature and possible toxicity of the other disinfectants and their by-products and they do not have the ability of the residual disinfection effect, so the treated water may be protected from recontamination by a small dose of chlorine. The quality of the raw water and the concentration and the nature of the contaminants may justify the decision for an alternative disinfection technique. 

SAW) workplace, followed by a consumable bare metal wire electrode. The arc melts the flux to produce a protective molten shield in the welding zone. infrared radiation, electrical, metal fumes, noise, ultraviolet radiation, ozone, nitrogen dioxide... 

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