Ionic composition

A quantitative method for reporting the ionic composition of a solution that takes into account the greater effect of more highly charged ions (jr). 

The ionic composition of a solution frequently is expressed by its ionic strength, p,... 

For gases, pure solids, pure liquids, and nonionic solutes, activity coefficients are approximately unity under most reasonable experimental conditions. For reactions involving only these species, differences between activity and concentration are negligible. Activity coefficients for ionic solutes, however, depend on the ionic composition of the solution. It is possible, using the extended Debye-Htickel theory, to calculate activity coefficients using equation 6.50... 

The potential of a redox reaction for a specific set of solution conditions, such as pH and ionic composition. 

Composition of the liquid environment The ionic composition, arising from dissolved salts and gases, has a considerable influence on the performance of inhibitors. In near-neutral aqueous systems the presence of certain ions tends to oppose the action of inhibitors. Chlorides and sulphates are the most common examples of these aggressive ions, but other ions, e.g. halides, sulphides, nitrates, etc. exert similar effects. The concentration of inhibitor required for protection will depend on the concentrations of these aggressive ions. Laboratory tests " have given some quantitative relationships... 

Two kinds of tantalum-containing initial solutions were chosen according to their ionic complex structure. The first one contained mostly TaF6 ions (Ta F = 1 18) while the second was characterized predominantly by TaF72 ions (Ta F = 1 6.5). The ionic composition of the solutions was determined by Raman spectroscopy. 

Molten salt investigation methods can be divided into two classes thermodynamic and kinetic. In some cases, the analysis of melting diagrams and isotherms of physical-chemical properties such as density, surface tension, viscosity and electroconductivity enables the determination of the ionic composition of the melt. Direct investigation of the complex structure is performed using spectral methods [294]. 

The calculation of the ionic composition (see Fig. 66) is based on the assumption that the salts dissociate completely, yielding potassium ions, K+, fluorine ions, F, and complex fluorotantalete ions, TaF or TaF72, as described below ... 

Fig. 66. Ionic composition of molten system KF - TaF5 at 900°C (after Agulyansky and Khomchenko [331]).

Of particular importance for the application are the effects of the external compression and the ionic composition of the outer solution on the swelling degree. The reason is that hydrogels usually exist in mineralized aqueous solutions (soil solution) and are affected by compression, for example, produced by the surrounding particles of the soil. Even in the absence of any external load the compression develops due to the gel swelling in a constrained volume. 

When the ionic composition varies within the range of very low salt concentrations, the swelling degree can reach its maximum [101]. This behavior is observed... 

In contrast to polyelectrolyte hydrogels, nonionic ones are almost insensitive to the ionic composition of the medium. In particular, the equilibrium swelling degree of a charge-free PAAm gel practically does not depend on the Cu2 + concentration (Fig. 4, curve 0) nor on the concentration of several other ions or on the pH value [101]. 

Figure 16. Effect of adding nitric oxide on ionic composition...

Fluid Liquid Tap water, Dist. water. De-ion. water, R-134a, Methanol, Isopropanol, Carbon tetrachloride solutions with several ionic compositions... 

Co(TPP) has been demonstrated to act as a catalyst for the electrocarboxylation of benzyl chloride and butyl bromide with CO - to give PhCHiCfOiOCH Ph and Bu0C(0)C(0)0Bu, respectively. The propo.sed mechanism involved Co(TPP)R and [Co(TPP-N-R) as intermediates (the latter detected by spectroscopy) in the catalytic production of free R or R-, which then reacted directly with Co(TPP) precipitated on graphite foil has been successfully used for the determination of organic halides, including DDT and 1,2,3,4,5,6-hexachlorocyclohexane (lindane), to sub-ppm level in aqueous solution. Deoxygenation of the solutions is not required, and the technique is moderately insensitive to the ionic composition of the solution. ... 

The Ionic Compositions of Intracellular Extracellular Fluids Differ Greatly... 

The ionic composition of the cell is maintained by operation of the sodium-potassium pump, which pumps ions from more dilute to more concentrated solutions the Na ions from the cytoplasm to the solution outside, and the K+ in the opposite... 

For pure water, [H+] = [OH ] and pH = 7. Any solution with pH = 7 is by definition a neutral solution. No matter what other solutes occur in a given solution, the product of hydrogen and hydroxide ion activities will always be 1CT14 at 25 °C. This may be noted that the value of this equilibrium constants alter with temperature, as do all equilibrium constants. For this reason at 230 °C, K = 10 11/1 and a neutral solution would have a pH of 5.7. This brief diversion specifically focusing attention on the ionic compositional aspects of water is quite relevant with regard to its role played as a leaching agent. 

There was no change in the conductance, without HC1, in spite of an increase in the temperature of about 10°C due to sonication (Table 9.5b). The ultrasound seemed to have increased the molecular solvation, therefore the activity of SO4-ions did not increase but remained more and more solvated due to complex ionic composition and charge distribution on the SO4 ions (Fig. 9.1). 

The first and very simple solid contact polymeric sensors were proposed in the early 1970s by Cattrall and Freiser and comprised of a metal wire coated with an ion-selective polymeric membrane [94], These coated wire electrodes (CWEs) had similar sensitivity and selectivity and even somewhat better DLs than conventional ISEs, but suffered from severe potential drifts, resulting in poor reproducibility. The origin of the CWE potential instabilities is now believed to be the formation of a thin aqueous layer between membrane and metal [95], The dominating redox process in the layer is likely the reduction of dissolved oxygen, and the potential drift is mainly caused by pH and p02 changes in a sample. Additionally, the ionic composition of this layer may vary as a function of the sample composition, leading to additional potential instabilities. 

A K is by nature descriptive, but in the Kt approach the value is taken over the range of chemical conditions considered in a model to be constant and predictive. This assumption, of course, cannot hold in the general sense. A K value varies sharply with pH, contaminant concentration, ionic composition of the fluid, and so on its measurement is specific to the fluid and sediment tested. It is imperative that the modeler keep these points in mind. 

Chemical composition and physical structure of the oxide copper minerals and the ionic composition of the slurry phase play important roles in the floatability of various oxide minerals. The oxide copper minerals are often porous, and in some cases, water soluble. Some of the oxide minerals tend to slime during grinding, and flotation of fine oxide minerals is rather difficult. 

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