Nitrate clouds

Mercuric Nitrate. Mercuric nitrate [10045-94-0] Hg(N02)2, is a colorless dehquescent crystalline compound prepared by the exothermic dissolution of mercury in hot, concentrated nitric acid. The reaction is complete when a cloud of mercurous chloride is not formed when the solution is treated with sodium chloride solution. The product crystallizes upon cooling. Mercuric nitrate is used in organic synthesis as the starting material and for the formulation of a great many other mercuric products. 

Pipette 25 mL of the standard 0.1 M silver nitrate into a 250 mL conical flask, add 5mL of 6M nitric acid and 1 mL of the iron(III) indicator solution. Run in the potassium or ammonium thiocyanate solution from a burette. At first a white precipitate is produced, rendering the liquid of a milky appearance, and as each drop of thiocyanate falls in, it produces a reddish-brown cloud, which quickly disappears on shaking. As the end point approaches, the precipitate becomes flocculent and settles easily finally one drop of the thiocyanate solution produces a faint brown colour, which no longer disappears upon shaking. This is the end point. The indicator blank amounts to 0.01 mL ofO.lM silver nitrate. It is essential to shake vigorously during the titration in order to obtain correct results. ... 

Chloratodimercuriacetaldehyde. OHC.C( Hg),Hg0.ClO2, mw 525.70, colorl prisms. Can be prepd by treating an excess of mercuric oxide in an aq soln of chloric acid with an ale soln of acetaldehyde. It is an extremely sensitive expl of the initiating type, exploding even when shaken under liq (Refs 1 3) Nitratodimercuriacetaldehyde. OHC.C( Hg).HgO.N02, mw 504.26, N 2.78%, colorl prisms from ale. Can be prepd by adding an ale soln of acetaldehyde to an aq soln of mercuric nitrate, acidified with nitric acid. Nearly insol in w. Puffs off on heating with evolution of a yellow cloud and Hg (Refs 1,2 3)... 

In its pure form, nitric acid is a liquid with a high vapor pressure (47.6 torr at 20°C), so that in the lower atmosphere HNO3 exists as a gas, in an aerosol or in a cloud droplet. When nitric acid reacts with a base a nitrate salt is produced, if... 

All of these species are very soluble in a rain or cloud drop and are an important source of atmospheric aerosols. For ammonia and ammonium, the condensed phases (I and s) represent approximately two-thirds of the total atmospheric burden, whereas for nitric acid and nitrates, about two-thirds is in the gas phase (Soderlund and Svensson, 1976). 

Atmospheric aerosols have a direct impact on earth s radiation balance, fog formation and cloud physics, and visibility degradation as well as human health effect[l]. Both natural and anthropogenic sources contribute to the formation of ambient aerosol, which are composed mostly of sulfates, nitrates and ammoniums in either pure or mixed forms[2]. These inorganic salt aerosols are hygroscopic by nature and exhibit the properties of deliquescence and efflorescence in humid air. That is, relative humidity(RH) history and chemical composition determine whether atmospheric aerosols are liquid or solid. Aerosol physical state affects climate and environmental phenomena such as radiative transfer, visibility, and heterogeneous chemistry. Here we present a mathematical model that considers the relative humidity history and chemical composition dependence of deliquescence and efflorescence for describing the dynamic and transport behavior of ambient aerosols[3]. 

The scare over, shouldn t normal men have felt like foolish rabbits running before the season began Not Carl Bosch. He was very sensitive to public opinion he d been criticized in France because the clouds of chlorine and mustard released without warning at Ypres had originated at Badische. In 1915, the Kaiser s rifles were about to become stovepipes when Bosch and Haber achieved their synthetic nitrate. 

The explosion efficiency is one of the major problems in the equivalency method. The explosion efficiency is used to adjust the estimate for a number of factors, including incomplete mixing with air of the combustible material and incomplete conversion of the thermal energy to mechanical energy. The explosion efficiency is empirical, with most flammable cloud estimates varying between 1 % and 10%, as reported by a number of sources. Others have reported 5%, 10%, and 15% for flammable clouds of propane, diethyl ether, and acetylene, respectively. Explosion efficiencies can also be defined for solid materials, such as ammonium nitrate. 

The following problem, taken to match the conditions in Figure 2 of reference 13, is typical of those solved in less than one minute on an IBM PC with this model "a cloud at 278 K contains 0.5 grams of liquid water per cubic meter of air. The atmo here of the cloud contains 5 ppb sulfur dioxide, 340 ppm carbon dioxide, 0.29 jig/m of nitrogen base, 3 xg/m of sulfate aerosol, and no nitrate aerosol. What is the pH of the cloud water Figure 4 shows the Variable Sheet after solution. 

During the dark, polar winter the temperature drops to extremely low values, on the order of-80°C. At these temperatures, water and nitric acid form polar stratospheric clouds. Polar stratospheric clouds are important because chemical reactions in the stratosphere are catalyzed on the surface of the crystals forming these clouds. The chemical primarily responsible for ozone depletion is chlorine. Most of the chlorine in the stratosphere is contained in the compounds hydrogen chloride, HCl, or chlorine nitrate, CIONO. Hydrogen chloride and chlorine nitrate undergo a number of reactions on the surface of the crystals of polar stratospheric clouds. Two important reactions are ... 

Nitrous acid/nitrite can also be oxidized in the aqueous solutions found in the atmosphere in the form of fogs, clouds, and particles. Nitrite is well known to be slowly oxidized in the dark to nitrate by dissolved oxygen in the liquid phase. However, it has been reported that the rate of this oxidation increases remarkably during freezing of the solution containing the nitrite (Takenaka et al., 1992, 1996). Figure 7.11, for example, shows the rate of nitrate formation in a nitrite solution at 25°C and in one with the cooling bath at — 21°C (Takenaka et al., 1992). This unusual phenomenon has also been observed with respect to the... 

As expected based on our knowledge of gas-phase chemistry, in addition to the Fenton type chemistry involving iron, photolysis of Os, H202, HONO, and HNO-, are all potential OH sources in clouds and fogs. In addition, the photolysis of nitrite, nitrate, and HOJ in aqueous solutions can also form OH. In short, there are many potential sources of OH in clouds and fogs. 

The use of the sun or moon as the light source allows one to measure the total column abundance, i.e., the concentration integrated through a column in the atmosphere. This approach has been used for a number of years (e.g., see Noxon (1975) for NOz measurements) and provided the first measurements of the nitrate radical in the atmosphere (Noxon et al., 1978). As discussed later in this chapter, such measurements made as a function of solar zenith angle also provide information on the vertical distributions of absorbing species. Cloud-free conditions are usually used for such measurements as discussed by Erie et al. (1995), the presence of tropospheric clouds can dramatically increase the effective path length (by an order of... 

Wurzler, S., A. I. Flossmann, H. R Pruppacher, and S. E. Schwartz, The Scavenging of Nitrate by Clouds and Precipitation. I. A Theoretical Study of the Uptake and Redistribution of NaNO, Particles and HNO, Gas by Growing Cloud Drops Using an Entraining Air Parcel Model, J. Atmos. Chem., 20, 259-280 (1995). 

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