Stoichiometry in solutions

With molarity and volume of solution, numbers of moles can be calculated. The number of moles may be used in stoichiometry problems just as moles calculated in any other way are used. Also, the number of moles calculated as in Chap. 10 can be used to calculate molarities or volumes of solution. 

EXAMPLE 11.13. Calculate the number of moles of AgCl that can be prepared by mixing 0.740 L of 1.25 MAgN03 with excess NaCl. 

AgN03 is in limiting quantity, and the problem is completed just as the prior example was done. 

EXAMPLE 11.15. a) Calculate the concentration of Zr + produced when excess solid zinc is treated with 100.0 mL of 6.000 M HCl. Assume no change in volume, (b) Repeat the problem with solid aluminum. 

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Most of these compounds are solids (though a few such as Pt(PEt3)3, Pt(PBu3)3 and Pt(PF3)4 are oils at room temperature). Their stoichiometry in solution has been studied, most particularly by31P NMR at low temperatures, to determine which species are present [47]. Table 3.8 shows that the coordination number is principally determined by the bulk of the ligand... 

Tetrakis(phenylethynyl)ethene (5) forms jr complexes with 2,4,7-trinitrofluoren-9-one (6) and (2,4,7-trinitrofluoren-9-ylidene)malonitrile (7)24. In the solid state the CT complexes show a 1 2 stoichiometry in solution (CHCI3) the purple-coloured complex between 5 and tetracyanoethylene shows a 1 1 stoichiometry. Such complexes may be of interest as potential new materials e.g. in the field of non-linear optics. 

In contrast to ammonia solutions, in which the metal cation effectively assumes a "bystander role in the formation of aggregate species, metal solutions in the low-dielectric-constant amines and ethers (e<> typically <10 at 300 K) show a multitude of metal-dependent species, both paramagnetic and diamagnetic. The general body of experimental information requires the presence of at least three distinct stoichiometries in solution (51, 53, 55),... 

The order of stabilities derived from Raman spectra appears to be UOi+ > Np02+ > Pu02+. For aqueous solutions of U01+ there is a linear correlation between the frequency of the 0=U=0 symmetric stretch (i cm-1) and the average number of ligands so that the stoichiometries in solutions can be estimated. Complex formation leads to weakening of the U02+ axial bonds in the order OH" > CO " > C2O4" > F" > SO " and this order reflects the corresponding decrease in stability constants (log /3).4 The unstable UO2 ion disproportionates as follows ... 

Reaction Stoichiometry in Solutions Acid-Base Titrations... 

According to Chapter 11, an acid is a substance that upon dissolving in water increases the concentration of hydronium (H30 ) ions above the value found in pure water, and a base is a substance that increases the concentration of hydroxide (OH ) ions above its value in pure water. Despite the careful language, it is commonplace to view acids and bases as substances that dissociate to give protons (which upon hydration become hydronium ions) and hydroxide ions, respectively. If the dissociation is complete, we can easily calculate the concentration of hydronium and hydroxide ions in the solution and then calculate the yield of acid-base neutralization reactions, and acid-base titrations, by the methods of stoichiometry in solution. But experience shows that many acid-base reactions do not go to completion. So, to predict the amount (or concentration) of... 

The formation of molecular complexes of defined stoichiometry in solution is usually accompanied by isosbestic points in titration spectra and by changes of... 

Unfortunately, copper complexes of Clip-Phen seemed to be able to adopt different geometries and stoichiometries in solution with the predominant presence of monomeric LCu species. Consequently their physico-chemical characterization was found difficult. 

More recently, some simple and yet highly effective amide-cleft-based anion receptors were synthesized by Crabtree and coworkers. Receptors 10-14 are based upon benzene or pyridine rings that are substituted in the 1- and 3-positions, or in the case of pyridine 2- and 6-positions, with either amide or sulfonamide groups. Proton NMR titrations in dichIoromethane-fi 2 were used to determine the association constants of the receptors with halide anions and acetate. All the receptors displayed solely 1 1 receptor anion complex stoichiometry in solution. except receptor 13 that showed behavior consistent... 

In the simplest case, a solvated guest (G) and a solvated host (H) interact with each other to form a complex [H G] in 1 1 stoichiometry in solution. The complex stability is evaluated by the equilibrium constant or association constant = a[H G]/ GaH. where ac, au, and a[H G] are... 

Irving-Williams stability order. Supporting data indicated a 2 2 (host/guest) complex stoichiometry in solution with a 1 2 stoichiomefiy in the presence of excess Cu ". Recently, rhodamine-based ferrocene derivatives have been used for cation sensing, for example, system 13 that responds to Cr +, which is an ion involved in various biochemical processes at the cellular level.An unusual anodic shift of —140 mV was observed in the Fc/Fc" " redox potential upon complexation of this cation in ethanol. 

The R-Ln-Hal formulae employed for indication of this class of compounds does not reflect their real structure but characterize only a general stoichiometry. In solutions these complexes exist, apparently, like Grignard reagents, in several forms, which are in equilibrium with each other. This is confirmed by the NMR spectroscopy data of PhYbl in a THE solution [67]. 

In this chapter, therefore, we deals with various processing factors for preparing thin films with preferred orientation, such as (1) the control of the structure of metal-organic precursors with considering the stoichiometry in solution for coating, (2) the selection... 

Alternating current titrations were performed with a Wayne Kerr B221 Autobalance bridge. For these titrations all donors and acceptors were dissolved in methylene chloride and made up to 10 M. The teflon conductivity cell was provided with 1 cm square gold electrodes. Adduct stoichiometries in solution were taken to be the guide for those of the solid adducts prepared by dry grinding. The stoichiometry for the latter compounds was checked by solid titration and found to confirm the ac data. 

The H and C NMR spectra of the bis(anthracene)cobaltate(l-) were found independent of the cation and it was shown that the stoichiometry in solution is identical to that observed in the solid state. The NMR spectra also indicate that both Ti" -anthracenes, bound to cobalt through one peripheral ring each, are equivalent. This is consistent with the previously observed patterns for the other TjAanthracene transition metal complexes " (see Figure 15.10.1). 

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