Solution, aqueous solid

Aqueous solutions do not usually ignite even though the solute is highly inflammable, e.g., an aqueous solution of ethanol containing less than 50% of the latter. When aqueous solutions of solid substances are heated on a crucible lid, they usually "spit" vigorously immediately before solidification. 

These three solids, sodium chloride, calcium chloride, and silver nitrate are similar, hence they are classified together. They all dissolve in water to form aqueous ions and give conducting solutions. These solids are called Ionic solids. 

Explain what happens to (a) the concentration of H,0+ ions in an acetic acid solution when solid sodium acetate is added (b) the percentage deprotonation of benzoic acid in a benzoic acid solution when hydrochloric acid is added (c) the pH of the solution when solid ammonium chloride is added to aqueous ammonia. 

The products of the reaction between bromide ions and permanganate ions, Mn04, in basic aqueous solution are solid manganese(IV) oxide, MnO>, and bromate ions. Balance the net ionic equation for the reaction. 

Here L, S, and J are the quantum numbers corresponding to the total orbital angular momentum of the electrons, the total spin angular momentum, and the resultant of these two. Hund predicted values of L, S, and J for the normal states of the rare-earth ions from spectroscopic rules, and calculated -values for them which are in generally excellent agreement with the experimental data for both aqueous solutions and solid salts.39 In case that the interaction between L and S is small, so that the multiplet separation corresponding to various values of J is small compared with kT, Van Vleck s formula38... 

Bouroushian M, Kosanovic T, Loizos Z, Spyrellis N (2002) Electrochemical formation of ZnSe from acidic aqueous solutions. J Solid State Electrochem 6 272-278... 

MoUn AN, Dikusar Al (1995) Electrochemical deposition of PbSe thin films from aqueous solutions. Thin Solid Films 265 3-9... 

Figure 9 summarizes the optical absorption spectra of the aqueous solutions or solid film of 1-9 and sodium gold(I) thiomalate (SGT) at ambient temperature. 

FIG. 5 Cyclic voltammograms of [Fe(CN)6] redox couple on bare (solid line), DNA-modified (heavy line), and HEDS-modified Au electrodes (dotted line). Electrol5de solution, aqueous each 5 mM of K4[Fe(CN)g] and K3[Fe(CN)g] containing 10 mM KCl scan rate 25 mV s temperature, 25°C electrode area, 0.02 cm (geometrical). 

Crystals with Frenkel or Schottky defects are reasonably ion-conducting only at rather high temperatures. On the other hand, there exist several crystals (sometimes called soft framework crystals ), which show surprisingly high ionic conductivities even at the room or slightly elevated temperatures. This effect was revealed by G. Bruni in 1913 two well known examples are Agl and Cul. For instance, the ar-modification of Agl (stable above 146°C, sometimes denoted also as y-modification ) exhibits at this temperature an Ag+ conductivity (t+ = 1) comparable to that of a 0.1m aqueous solution. (The solid-state Ag+ conductivity of a-Agl at the melting point is actually higher than that of the melt.) This unusual behaviour can hardly be explained by the above-discussed defect mechanism. It has been anticipated that the conductivity of ar-Agl and similar crystals is described... 

Adsorption is a physicochemical process whereby ionic and nonionic solutes become concentrated from solution at solid-liquid interfaces.3132 Adsorption and desorption are caused by interactions between and among molecules in solution and those in the structure of solid surfaces. Adsorption is a major mechanism affecting the mobility of heavy metals and toxic organic substances and is thus a major consideration when assessing transport. Because adsorption is usually fully or partly reversible (desorption), only rarely can it be considered a detoxification process for fate-assessment purposes. Although adsorption does not directly affect the toxicity of a substance, the substance may be rendered nontoxic by concurrent transformation processes such as hydrolysis and biodegradation. Many chemical and physical properties of both aqueous and solid phases affect adsorption, and the physical chemistry of the process itself is complex. For example, adsorption of one ion may result in desorption of another ion (known as ion exchange). 

Since it is useful to know what state each reagent is in, we often designate the state in the equation. The modern practice is to add to the formula the designation in parentheses (s) for solid, (l) for liquid, (g) for gas, and (aq) for aqueous solution. Thus, a reaction of silver nitrate with sodium chloride in aqueous solution, yielding solid silver chloride and aqueous sodium nitrate, may be written as... 

A great many metal complexes are prepared by reactions carried out in aqueous solutions. Consequently, solid complexes are frequently obtained as hydrates. Water is also a potential ligand so various possibilities exist for compounds to be prepared with water held in both ways. For example, [Cr(H20)4Cl2]Cl-2ff20 and [Cr(H20)5Cl]Cl2-ff20 have the same formula, but they are obviously different compounds. In the first case, two chloride ions are coordinated and one is present as an anion, whereas in the second case the numbers are reversed. Many other examples of hydrate isomerism are known. 

Akiyoshi, M., Deguchi, T., Sanemasa, I. (1987) The vapor saturation method for preparing aqueous solutions of solid aromatic hydrocarbons. Bull. Chem. Soc. Jpn. 60, 3935-3939. 

Certain pairs of enantiomers, such as 25°C solutions of camphor in aqueous ethanol (Fig. 26a), 2,2,5,5-tetramethyl-l-pyrrolidinoxy-3-carboxylic acid in chloroform (Fig. 26b), or carvoxime in hexane (Fig. 26c), cocrystallize throughout the entire range of mole fractions. The crystals that are in equilibrium with the saturated liquid solution are solid solutions (mixed crystals), since they constitute a single phase. The racemic solid solution is termed a pseudoracemate [141]. 

Glynn, P. D., E. J. Reardon, L. N. Plummer and E. Busenberg, 1990, Reaction paths and equilibrium end-points in solid-solution aqueous-solution systems. Geochimica et Cosmochimica Acta 54,267-282. 

The rate of adsorption from dilute aqueous solutions by solid adsorbents (zeolites) is a highly significant factor for applications of this process for water quality control. 

The preparation of aqueous solutions from solids is usually performed after the sample has been ground to a powder of uniform size. Sometimes, samples can be only sparingly soluble in water and therefore organic solvents may be used to dissolve the sample. Organic solvents can increase the sensitivities of atomic spectrometric analyses as a result of increases in the efficiencies of the nebulization of the analyte solutions. When organic solvents are used to dissolve samples non-selective ligands should be added to complex ionic species that would otherwise be insoluble in the organic solvent. 

The geochemical fate of most reactive substances (trace metals, pollutants) is controlled by the reaction of solutes with solid surfaces. Simple chemical models for the residence time of reactive elements in oceans, lakes, sediment, and soil systems are based on the partitioning of chemical species between the aqueous solution and the particle surface. The rates of processes involved in precipitation (heterogeneous nucleation, crystal growth) and dissolution of mineral phases, of importance in the weathering of rocks, in the formation of soils, and sediment diagenesis, are critically dependent on surface species and their structural identity. 

Approach to Equilibrium in Solid Solution-Aqueous Solution Systems The KCl-KBr-H20 System at 25 °C... 

Thermodynamic calculations based on the compositional dependence of the equilibrium constant are applied to solubility data in the KCl-KBr-H20 system at 25°C. The experimental distribution coefficient and activity ratio of Br /Cl in solution is within a factor of two of the calculated equilibrium values for compositions containing 19 to 73 mole percent KBr, but based on an assessment of uncertainties in the data, the solid solution system is clearly not at equilibrium after 3-4 weeks of recrystallization. Solid solutions containing less than 19 and more than 73 mole percent KBr are significantly farther from equilibrium. As the highly soluble salts are expected to reach equilibrium most easily, considerable caution should be exercised before reaching the conclusion that equilibrium is established in other low-temperature solid solution-aqueous solution systems. 

Equilibrium between simple salts and aqueous solutions is often relatively easily demonstrated in the laboratory when the composition of the solid is invariant, such as occurs in the KCI-H2O system. However, when an additional component which coprecipitates is added to the system, the solid composition is no longer invariant. Very long times may be required to reach equilibrium when the reaction path requires shifts in the composition of both the solution and solid. Equilibrium is not established until the solid composition is homogeneous and the chemical potentials of all components between solid and aqueous phases are equivalent. As a result, equilibrium is rarely demonstrated with a solid solution series. 

The final solid solution-aqueous solution compositions of Table I will fall into one of three catagories (1) they will either be at equilibrium, (2) at stoichiometric saturation, or (3) correspond to some non-equilibrium state. 

This permits provisional calculation of the compositional dependence of the equilibrium constant and determination of provisional values of the solid phase activity coefficients (discussed below). The equilibrium constant and activity coefficients are termed provisional because it is not possible to determine if stoichiometric saturation has been established without independent knowledge of the compositional dependence of the equilibrium constant, such as would be provided from independent thermodynamic measurements. Using the provisional activity coefficient data we may compare the observed solid solution-aqueous solution compositions with those calculated at equilibrium. Agreement between the calculated and observed values confirms, within the experimental data uncertainties, the establishment of equilibrium. The true solid solution thermodynamic properties are then defined to be equal to the provisional values. 

Although equilibrium was not established, it was more closely approached in the KCl-KBr-H20 system than in carbonate systems. For example, in a similar analysis of the strontianite-aragonite solid solution system (4 ), it was found that the experimental distribution coefficient for Sr substitution from seawater into aragonite is 12 times larger than the expected equilibrium value. Most of the distribution coefficients for the KCl-KBr-H20 system are within a factor of two of the equilibrium value, but clearly not at equilibrium. Considerable caution should be exercised before reaching the conclusion that equilibrium is established at relatively low temperatures in other solid solution-aqueous solution systems. 

Most thermodynamic data for solid solutions derived from relatively low-temperature solubility (equilibration) studies have depended on the assumption that equilibrium was experimentally established. Thorstenson and Plummer (10) pointed out that if the experimental data are at equilibrium they are also at stoichiometric saturation. Therefore, through an application of the Gibbs-Duhem equation to the compositional dependence of the equilibrium constant, it is possible to determine independently if equilibrium has been established. No other compositional property of experimental solid solution-aqueous solution equilibria provides an independent test for equilibrium. If equilibrium is demonstrated, the thermodynamic properties of the solid solution are also... 

Figure 1. Triangular solid solution-aqueous solution equilibria...

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