Water, theories

Arthur, C.L., Potter, D., Bucholz, K., and Pawliszyn, J.B. 1992. Solid phase microextraction for the direct analysis of water Theory and practice. LC-GC 10 656-661. 

Vaslow suggested that his results were not inconsistent with water theories involving varying cluster sizes, such as those of Nemethy and Scheraga or Luck. It is not obvious, however, by which mechanism the clusters may effect a sudden change in solute behavior at a critical concentration. Vaslow dismisses the possibility that the anomalies depend... 

Apart from Poples model, few water theories accommodate the possibility that hydrogen bonds may not be linear or close to linear. Indeed, practically all major theories of water structure assume that highly bent hydrogen bonds were relatively unimportant. 

J. Krogh-Moe. Acta Chem. Scand. 10, 331-2 (1956). Electrical conductivity in water theory. 

Three types of surface are in use for water simulations. The first consists of simple empirical models based on the LJ-C potential. There seems to be no purpose in continuing to develop and use such models as they give little, if any, new information. A second group attempts to improve the accuracy of the potential using semiempirical methods based on a comprehensive set of experimental data. These models allow for physical phenomena such as intramolecular relaxation, electrostatic induced terms, and many-body interactions, all of which are difficult to incorporate correctly in liquid water theories. There is room for much more work in these areas. The third group makes use of the most advanced ab initio methods to develop accurate potentials from first principles. Such calculations are now converging with parameterized surfaces based on accurate semiempirical models. Over the next few years it seems very likely that the continued application of the second and third approaches will result in a potential energy surface that achieves quantitative accuracy for water in the condensed phase. 

Wilhelm Homberg, Maniere d extraire un sel volatile acide mineral en forme seche, Histoire et Memoires de VAcademie Royale des Sciences 1666-99,11 vols. (Paris, 1729-33), 10 202-08 (paper read on 31 December 1692) Principe, Wilhelm Homberg, chapter 3 on Helmont s water theory see Walter Pagel, Joan Baptista van Helmont (Cambridge Cambridge University Press, 1982), esp. 49-60. 

P. A. Marrone, T. A. Arias, W. A. Peters and J. W. Tester, Solvation Effects on Kinetics of Methylene Chloride Reactions in Sub- and Supercritical Water Theory, Experiment, and Ab-Initio Calculations, J. Phys. Chem. A, 102, 7013-7028 (1998). 

The supercritical-water theory describes the elfects of high temperatures and pressures in aqueous systems when conditions are reached under which supercritical water is likely. Supercritical water is known to have a strong solvent action towards organic compounds and extreme chemical activity. Sonochemical effects are possible inside the supercritical water layer surrounding a transient bubble. At the present time, no direct evidence for the generation of supercritical water in ultrasound fields has been found experimentally. 

If the water is deeper than 200 m, the linear long wave equation should be applied. For the region shallower than 200 m, the shallow water theory with a term for bottom friction included should be used. This shallow water theory includes the first order approximation of the amplitude dependent dispersion. Under special conditions, the term for frequency dependent dispersion should be included. If the purpose of the simulation is to determine the runup height, the equations of higher order approximations are not necessary. 

The high enthalpy water theory may explain, at least in part, the reason why cyclodextrins tend to have higher affinities for guest molecules than do linear dextrins. Another reason may be that of strain relaxation within cyclodextrin molecules. Saenger has suggested (g6) that in a cyclodextrin the uncomplexed molecule is in a slightly strained conformation due to rotation of one of the... 

The water theory (sometimes called the Arrhenius theory). 

The theory of solvent systems conforms to the experimental fact that there are many other substances besides those containing hydrogen which exhibit typical acid properties. But it makes the definitions of acid and base as rigidly dependent upon the solvent as does the water theory. 

For example, for molecular acids in water the equation reduces to an expression equivalent to that of the water theory ... 

These definitions include both the Br0nsted and the solvent-systems theories as well as the water theory. The list of bases according to the Lewis theory is identical with that according to... 

However, the formation of a salt is not always the result. According to the water theory of acids and bases, a salt invariably resulted from neutralization but salt formation is obviously unnecessary, as the following examples show ... 

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