Initial ion concentration

Problems that involve polyprotic acids can be divided into as many sub-problems as there are hydrogen atoms that dissociate. The ion concentrations that are calculated for the first dissociation are substituted as initial ion concentrations for the second dissociation, and so on. You can see this in the following Sample Problem. 

Figure 7.4 shows the conditional solubility product of magnesium silicafe as a function of pH (at an initial ion concentration of 1 mM). The region above the curve represents a system of higher concentration... 

Figure 7 illustrates the complexity of transient pore formation (45) under conditions that closely resemble physiologic conditions. The initial ion concentration imbalance across the membrane develops a strong local electric field that induces the formation of a pore. The pore formation starts with the creation of a single water defect in terms of a chain of water molecules, which spans the entire membrane. The defect then expands within less than 1 ns through redistribution of lipid head groups... 

The maximal binding capacity was determined at certain pH values, using both batch and column methods. In the batch methods, the total amount of the metal salt was always in 2-3 fold excess over the theoretical ion capacity, and the metal uptake by the polymers was calculated from the dif-ference.s in metal concentration prior and after the equilibration. In the column method. 500 1000 ml of 0.1- 0.5 M metal sulphate solution was passed through a 10 50 g polymer in a column at a rate of 1 ml/min. Tractions were collected until the initial ion concentration was achieved. The metal uptake was calculated again from the total amount of metal ions recovered in solution, by difference. 

The fluorescence lifetime of XeF is short ( 15 ns) and thus the ionic recombination reaction controls the observed rate of decay of emission when the initial ion concentrations are very low. 

The rate constants for the first three reactions in this scheme were obtained by isolating the excited-state reaction process using low xenon pressures and initial ion concentrations [67]. For the quenching reactions of XeBr literature rate constants were used [78-82], From the above reaction scheme and these rate... 

Figure 19.8. Effects of initial ion concentration and voltage gradient on the electrokinetic transport parameters for sulfate, nitrate, and ammonium [from Lohner, Katzoreck, and Tiehm (2008a)].

The isotherms of ion adsorption onto silica surfaces were determined by the depletion method and calculated from the difference between initial ion concentration and the one measured in the supernatant after 24 hours of equilibration. The isotherms of cation and anion adsorbtion r(C) (Figure 36.4) show their nonequivalent character (adsorption of cations is always greater than of anions and increases in the order Li < Na < K). 

Step 1 Determine initial ion concentrations Because we started with a 0.15 M sodium acetate solution, the concentrations of the ions (Na and CH3COO ) are also equal to 0.15 M after dissociation. Of these ions, only the acetate ion will react with water ... 

The production cost and reusability of the adsorbents are the most effective parameters for the sorbents in the wastewater treatment systems. Therefore, reusability of the super absorbent hydrogel was also evaluated for the Cr (VI) ions removal studies. During these studies, the optimized super absorbent hydrogel A2 adsorption condition, (initial ion concentration), which can provide maximum ion removal, was used. 

Chitosan sorbents, cross-hnked and grafted with amido or carboxyl groups, were also prepared and their sorption properties for Cu(II) and CifVI) uptake were studied (Kyzas et al., 2009). Equilibrium sorption experiments were carried out at different pH values and initial ion concentrations. The equilibrium data were successfully fitted to the Langmuir-Freundlich (L-F) isotherm. The calculated maximum sorption capacity of the carboxyl grafted sorbent for Cu(II) was found to be 318 mg/g at pH 6, while the respective capacity for Cr(VI) uptake onto the amido-grafted soibent was found to be 935 mg/g at pH 4. 

Plan First, we decide which slightly soluble salt could form, look up its value in Appendix C, and write a dissolution equation and ion-product expression. To see whether mixing these solutions forms the precipitate, we find the initial ion concentrations by calculating the amount (mol) of each ion from its concentration and volume, and dividing by the total volume because each solution dilutes the other. Finally, we substitute these concentrations to calculate and compare with AT p. 

Criteria for Precipitation and Its Completeness—To determine whether a slightly soluble solute will precipitate from a solution, the ion product, Qsp, is compared with the solubility product constant, K p. Q p is based on the initial ion concentrations in a solution. K p, on the other hand, is based on the equilibrium ion concentrations in a saturated solution. If Qgp > K p, precipitation will... 

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