Gas atmosphere

Ketkar and co-workers developed a new analytical method for measuring trace levels of atmospheric gases.The analysis of a sample containing 40.0 parts per thousand (ppt) 2-chloroethylsulfide yielded the following results... 

Typical examples of gaseous samples include automobile exhaust, emissions from industrial smokestacks, atmospheric gases, and compressed gases. Also included with gaseous samples are solid aerosol particulates. 

The short-term exposure of humans, animals, and plants to gaseous pollutants is more severe than that for pollutants in other matrices. Since the composition of atmospheric gases can show a substantial variation over a time, the continuous monitoring of atmospheric gases such as O3, CO, SO2, NH3, H2O2, and NO2 by in situ sampling is important. 

Gas-sensing electrodes have been developed for a variety of gases, the characteristics for which are listed in Table 11.4. The composition of the inner solution changes with use, and both it and the membrane must be replaced periodically. Gas-sensing electrodes are stored in a solution similar to the internal solution to minimize their exposure to atmospheric gases. 

Simultaneous Loss by Radiation The heat transferred by radiation is often of significant magnitude in the loss of heat from surfaces to the surroundings because of the diathermanous nature of atmospheric gases (air). It is convenient to represent radiant-heat transfer, for this case, as a radiation film coefficient which is added to the film coefficient for convection, giving the combined coefficient for convection and radiation (h + hf In Fig. 5-7 values of the film coefficient for radiation are plotted against the two surface temperatures for emissivity = 1.0. 

Extruded polystyrene sheet - Alternatives currently include HCFC-22, hydrocarbons, injected carbon dioxide, and HFC-152a. In the long term, these same alternatives (except for HCFC-22) will be used, along with possible use of atmospheric gases. 

Breathing consists of the cyclic action of the lungs to inspire and expire atmospheric gases. Inspiration occurs when the diaphragm and intercostal muscles contract, generating a negative pressure in the pleura surrounding... 

Coefficients of isaturiatiOn of atmospheric gases in sea-water. 21.23, Properties ol sea-water of different salinities... 

Table 21.22 Saturated solubilities of atmospheric gases in sea-water at various temperatures Concentrations of oxygen, nitrogen and carbon dioxide in equilibrium with 1 atm (lOI 325 N m ) of designated gas...

Note, atmospheric gases are present in sea-water in approximately the following quantities ... 

It is less conunonly known that methane was one of the original atmospheric gases and is a normal product of the microbial decomposition of organic matter under anaerobic conditions. Bacteria involved in production of methane are unique in their metabolism and other properties. The balanced... 

Table 3-6 Biological sources of Earth s major atmospheric gases"...

Natural mobilization includes chemical, mechanical, and biological weathering and volcanic activity. In chemical weathering, the elements are altered to forms that are more easily transported. For example, when basic rocks are neutralized by acidic fluids (such as rainwater acidified by absorption of CO2), the minerals contained in the rocks can dissolve, releasing metals to aqueous solution. Several examples are listed below of chemical reactions that involve atmospheric gases and that lead to the mobilization of metals ... 

C07-0091. List the region of the atmosphere and the atmospheric gases that absorb light in each of the following spectral regions (a) less than 200 nm (b) 240 to 310 nm. 

Example uses Henry s law to determine the concentrations of atmospheric gases that dissolve in water, and our Chemistry and Life Box addresses an important consequence of Henry s law. 

The ozone hole would almost certainly be much worse if chemists had not studied the reactions of CFCs with atmospheric gases before ozone depletion was discovered. The 1995 Nobel Prize in chemistry was awarded to the three pioneers in this effort. A German chemist, Paul Crutzen, discovered how ozone concentration is regulated in a normal stratosphere, while two Americans, F. Sherwood Rowland and Mario Molina, showed that CFCs can destroy ozone. These studies of molecular reactions allowed quick determination that CFCs are a likely cause of ozone depletion and led to the international restrictions described above. 

Figure 1 The solubility of the principal atmospheric gases in seawater, as a function of temperature. Units are millilitres of gas contained in a litre of seawater of salinity 35 psu, assuming an overlying atmosphere purely of each gas. Note that salinity is defined in terms of a conductivity ratio of seawater to a standard KC1 solution and so is dimensionless. The term practical salinity unit , or psu, is often used to define salinity values, however. It is numerically practically identical to the old style unit of parts per thousand by weight...

Elastomers function as a barrier to either moisture or atmospheric gases (oxygen, nitrogen, and argon). This property is important in maintaining product integrity for lyophilized or liquid products subject to decomposition by water vapor or oxygen. 

On a global scale, there is little doubt that human activities associated with energy production, primarily of fossil fuels, have over the last few decades, altered the composition of atmospheric gases. World carbon emissions are expected to exceed 1990 levels by 39 percent in 2010. By 2020, this figure will be closer to 70 percent Two thirds of the total increase in carbon emissions will occur in non-industrialized countries. 

The purify of the water changes constantly during the water cycle. As rain falls through the air, for example, the water dissolves some atmospheric gases such as oxygen, carbon dioxide, and in industrial regions also such air pollutants as sulfur dioxide and oxides of nitrogen. Still more carbon dioxide... 

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