Solubility Categories

Solubility Categories Aqueous solubilities are found to be expressed in categorical terms such as practically insoluble , slightly soluble , soluble , miscible , or similar terms. If a compound is miscible in any proportions, this is often denoted by oo . 

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The average error in the external prediction was about +0.8 log unit. Although this range was still not suitable to predict the precise solubility values of external compounds, it was sufficient to rank compounds in different solubility categories and to use it for the filtering of compounds in virtual databases. 

Figure 4 shows pesticide volatilization as affected by soil depths of 1, 5, and 10 cm with water evaporation (E) equal to 0.25 cm/d. Since the concentration is inversely proporational to the depth of soil containing the 1 kg/ha of pesticide, the ratio of the concentrations roughly explains the initial relative volatilization rates. The very water soluble (Category III) compounds appear to approach a constant volatilization rate regardless of depth because their volatilization is controlled by diffusion of the chemical through the boundary layer above the soil surface as well as by the rate of movement upward to the soil surface. 

Sodium and potassium bases are in the high-solubility category of neutralizing agents (Table 12.7). Their major advantage is ease of application. The most common high-... 

Classify each of the following solutes into the approximate solubility categories of Table 7.3. The numbers in parentheses are the grams of solute that will dissolve in 100 g of water at the temperature indicated. 

The overall extraction process is sometimes subdivided into two general categories according to the main mechanisms responsible for the dissolution stage (/) those operations that occur because of the solubiHty of the solute in or its miscibility with the solvent, eg, oilseed extraction, and (2) extractions where the solvent must react with a constituent of the soHd material in order to produce a compound soluble in the solvent, eg, the extraction of metals from metalliferous ores. In the former case the rate of extraction is most likely to be controUed by diffusion phenomena, but in the latter the kinetics of the reaction producing the solute may play a dominant role. 

Properties. HydroxyethjIceUulose [9004-62-0] (HEC), is a nonionic polymer. Low hydroxyethyl substitutions (MS = 0.05-0.5) yield products that are soluble only in aqueous alkali. Higher substitutions (MS > 1.5) produce water-soluble HEC. The bulk of commercial HEC falls into the latter category. Water-soluble HEC is widely used because of its broad compatibiUty with cations and the lack of a solution gel or precipitation point in water up to the boiling point. The MS of commercial HEC varies from about 1.8 to 3.5. The products are soluble in hot and cold water but insoluble in hydrocarbon solvents. HEC swells or becomes pardy to mosdy soluble in select polar solvents, usually those that are miscible with water. 

The vehicle system of water-borne coatings can be divided into two categories water-emulsifiable vehicles and water-soluble vehicles. 

Pesticides include the broad categories of insecticides, fungicides, rodenticides, and herbicides. Insecticides in common use fall into three categories. The chloroinsec-ticides have chlorine in their structure. They are less soluble than the other insecticide forms and much less biodegradable (i.e., more persistent). While they are less acutely toxic, several have been identified as potential carcinogens. Carbamatea are a relatively new form of pesticide. They are less persistent and less... 

Humic substances in sediments and soils have commonly been, defined as heteropolycondensates of decomposing plant and animal detritus 46. For lack of a better structural definition, these macromolecular substances have been divided into three categories fulvic acids and humic acid and humin. Fulvic acids and humic acids are soluble in dilute alkaline solutions, whereas humin is insoluble. 

Condensed phase interactions can be divided roughly into two further categories chemical and physical. The latter involves all purely physical processes such as condensation of species of low volatility onto the surfaces of aerosol particles, adsorption, and absorption into liquid cloud and rainwater. Here, the interactions may be quite complex. For example, cloud droplets require a CCN, which in many instances is a particle of sulfate produced from SO2 and gas-particle conversion. If this particle is strongly acidic (as is often the case) HNO3 will not deposit on the aerosol particle rather, it will be dissolved in liquid water in clouds and rain. Thus, even though HNO3 is not very soluble in... 

Most aqueous equilibria fall into three broad categories proton transfer, solubility, or complexation. The nature of the major species in the solution determines which category of equilibrium we need to consider. 

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