Compounds from aqueous solutions physical properties

Sodium bromide [7647-15-6] NaBr, the most common and available alkali bromide, is a salt of hydrobromic acid (see Bromine COMPOUNDS). Sodium bromide crystallizes from aqueous solution as a di ydj 2LX.e[13466-08-5] NaBr-2H20, below 51 C. Above 51°C, it crystallizes as the anhydrous compound. Crystals of the dihydrate belong to the monoclinic system and have lattice parameters a = 659 pm, b = 1020 pm, and c = 651 pm. The anhydrous crystal belongs to the cubic system, a = 596 pm. Other physical properties of the anhydrous salt are Hsted in Table 1. The anhydrous salt is hygroscopic but not dehquescent. 

Physical and chemical as well catalytical properties of basic oxides depend on the nature of the compound from which the oxide has been prepared. MgO is mostly prepared from soluble magnesium salts, (the nitrate, chloride and acetate are mostly used) by precipitation from aqueous solution and calcination of Mg(0H)2<... 

Isomaltulose, also known as Palatinose (lUPAC name (2R,3R,4S,5R,6S)-2-(hydroxymethyl)-6-[[(2R,3R,4S)-3,4,5-trihydroxy-5-(hydroxymethyl)oxolan-2-yl]methoxy] oxane-3,4,5-triol), and sucrose have similar physical and organoleptic properties. Isomaltulose (Palatinose ) is a reducing, free-flowing, non-hygroscopic crystalline compound which can be crystallized easily from aqueous solutions with one mole crystal water. Crystalline isomaltulose (Palatinose ) melts at 123-124 The crystal structure and... 

Ghromium(III) Compounds. Chromium (ITT) is the most stable and most important oxidation state of the element. The E° values (Table 2) show that both the oxidation of Cr(II) to Cr(III) and the reduction of Cr(VI) to Cr(III) are favored in acidic aqueous solutions. The preparation of trivalent chromium compounds from either state presents few difficulties and does not require special conditions. In basic solutions, the oxidation of Cr(II) to Cr(III) is still favored. However, the oxidation of Cr(III) to Cr(VI) by oxidants such as peroxides and hypohaUtes occurs with ease. The preparation of Cr(III) from Cr(VI) ia basic solutions requires the use of powerful reducing agents such as hydra2ine, hydrosulfite, and borohydrides, but Fe(II), thiosulfate, and sugars can be employed in acid solution. Cr(III) compounds having identical counterions but very different chemical and physical properties can be produced by controlling the conditions of synthesis. 

In the broadest sense, coordination chemistry is involved in the majority of steps prior to the isolation of a pure metal because the physical properties and relative stabilities of metal compounds relate to the nature and disposition of ligands in the metal coordination spheres. This applies both to pyrometallurgy, which produces metals or intermediate products directly from the ore by use of high-temperature oxidative or reductive processes and to hydrometallurgy, which involves the processing of an ore by the dissolution, separation, purification, and precipitation of the dissolved metal by the use of aqueous solutions. 4... 

Elemental composition Ni 22.85%, C 46.75%, H 5.49%, O 24.91%. The compound may be characterized by its physical properties, elemental analysis, and by IR, UV and NMR spectra and x-ray diffraction data. A benzene or chloroform solution may be injected directly into a GC column and may be identified from its mass spectra. The characteristic mass ions for its identification by GC/MS are 58, 60, 100, 257. The aqueous solution or the nitric acid extract may be analyzed either by flame or furnace AA, or by ICP-AES to determine nickel content. 

Elemental composition Os 74.82%, 0 25.18%. The compound can be identified by its physical properties, such as, odor, color, density, melting-, and boiling points. Its acrid odor is perceptible at concentrations of 0.02 mg/hter in air. The oxide also produces an orange color when a small amount of the compound or its aqueous solution is mixed with an aqueous solution of ammonia in KOH (see Reactions). Aqueous solution of the tetroxide may be analyzed for osmium by AA or ICP spectrometry (see Osmium). Vapors of the tetroxide may be purged from an aqueous solution by helium, adsorbed over a trap, and desorbed thermally by helium onto a GC. Alternatively, a benzene or carbon tetrachloride solution may be injected onto the GC and the compound peak identified by mass spectrometry. The characteristic mass ions for its identification should be 190 and 254. 

Elemental composition P 38.73%, H 1.26%, O 60.01%. The compound may be identified by physical properties alone. It may be distinguished from ortho and pyrophosphates by its reaction with a neutral silver nitrate solution. Metaphosphate forms a white crystalline precipitate with AgNOs, while P04 produces a yellow precipitate and P20 yields a white gelatinous precipitate. Alternatively, metaphosphate solution acidified with acetic acid forms a white precipitate when treated with a solution of albumen. The other two phosphate ions do not respond to this test. A cold dilute aqueous solution may be analyzed for HPO3 by ion chromatography using a styrene divinylbenzene-based low-capacity anion-exchange resin. 

Sodium is analyzed in aqueous solution by AA or ICP methods. Phosphate anion is measured by colorimetric methods (See Phosphoric Acid) or ion chromatography. The solution must be diluted appropriately. The compound is also identified from its physical properties. 

Elemental composition Sn 45.56%, Cl 54.44%. The compound may be identified from its physical properties. An aqueous solution may be analyzed by AA, ICP and other techniques to determine tin content. The compound may be dissolved in toluene or carbon tetrachloride, diluted sufficiently, and analyzed by GC/MS. 

A number of experimental techniques by measurements of physical properties (interfacial tension, surface tension, osmotic pressure, conductivity, density change) applicable in aqueous systems suffer frequently from insufficient sensitivity at low CMC values in hydrocarbon solvents. Some surfactants in hydrocarbon solvents do not give an identifiable CMC the conventional properties of the hydrocarbon solvent solutions of surfactant compounds can be interpreted as a continuous aggregation from which the apparent aggregation number can be calculated. Other, quite successful, techniques (light scattering, solubilization, fluorescence indicator) were applied to a number of CMCs, e.g., alkylammonium salts, carboxylates, sulfonates and sodium bis(2-ethylhexyl)succinate (AOT) in hydrocarbon solvents, see Table 3.1 (Eicke, 1980 Kertes, 1977 Kertes and Gutman, 1976 Luisi and Straub, 1984 Preston, 1948). 

Many properties of electrolytic solutions are additive functions of the properties of the respective ions this is at once evident from the fact that the chemical properties of a salt solution are those of its constituent ions. For example, potassium chloride in solution has no chemical reactions which are characteristic of the compound itself, but only those of potassium and chloride ions. These properties are possessed equally by almost all potassium salts and all chlorides, respectively. Similarly, the characteristic chemical properties of acids and alkalis, in aqueous solution, are those of hydrogen and hydroxyl ions, respectively. Certain physical properties of electrolytes are also additive in nature the most outstanding example is the electrical conductance at infinite dilution. It will be seen in Chap. II that conductance values can be ascribed to all ions, and the appropriate conductance of any electrolyte is equal to the sum of the values for the individual ions. The densities of electrolytic solutions have also been found to be additive functions of the properties of the constituent ions. The catalytic effects of various acids and bases, and of mixtures with their salts, can be accounted for by associating a definite catalytic coefl5.cient with each type of ion since undissociated molecules often have appreciable catalytic properties due allowance must be made for their contribution. 

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