Concentration equilibrium ratios

A number of other equilibrium ratios that are more easily measured than Kg frequently appear in the scientific literature—for example, the concentration equilibrium ratio Kc, defined to be... 

Steam. Steam is a potential poison of nickel catalysts under extremely high steam concentrations and low hydrogen concentrations. This is apparent in Figure 11 where the equilibrium ratio of Ph2/Fh2o over Ni and over Ni(active) is plotted as a function of temperature for the following reactions ... 

That is, at low solute concentrations, the ratio of the concentrations of the solutes in the two solutions is constant." Thus, measurement of the solution compositions in equilibrium with one another at low concentrations where both solutions obey Henry s law yields a value of k. With the value of k determined, one can obtain the activities of the solute in solvent A, if the activities of the solute in solvent B are known.Jj... 

Octanol-Water Partition Coefficient (Kq )—The equilibrium ratio of the concentrations of a chemical in TT-octanol and water, in dilute solution. 

The Rvalues are partition coefficients. The assumption that these are real constants Is seldom completely true, of course, because equilibrium Is rarely achieved and because the equilibrium ratios generally are not the same for all concentration levels. Moreover, It Is difficult to find the needed Information, and one must often accept a single literature value as typical of a given Intermedia transfer. When the organic content of the soli Is known or can be accurately estimated, one can usually derive Kgw from a compound s aqueous solubility, S, or Its octanol/water partition coefficient, KQW (14) Values of Kpa, namely "bloconcentratlon factors" between feed and meat animals (15,16), can also be derived from S or KQW. Bloconcentratlon factors between water and fish are well documented (14) A considerable weakness exists In our perception of the proper estimates to use for partition coefficients between soli and edible crop materials. Thus, at one time, two of the present authors used a default value of Kgp = 1 for munitions compounds that are neither very soluble In water nor very Insoluble (4) at another time, a value of was assumed for compounds with very low values of Ksw, l.e., polybromoblphenyls (6). 

The right-most term is similar to the familiar PDT formula except that the indicator function combinations forbid binding of solution molecules to the defined inner shell. That last factor is recognized as the Boltzmann factor of the hydration free energy that would result if inner-shell binding were prohibited. The Km are recognizable ratios of equilibrium concentrations - equilibrium constants - that are discussed... 

From the measured activity concentrations the ratios of the free activity to the total activity fj = cjf/cj (j = 1>2), the corresponding values of fp and the equilibrium equivalent radon concentration c q and F, respectively, were calculated. 

The process for isomerization of EB requires that some fraction of the feed be maintained in a saturated state, as described in Sections 14.4.1.1 and 14.4.1.2. The ability to isomerize the EB is affected by the naphthene concentration and constrained by the equilibrium ratio of EB/xylenes at the reaction temperature. Use of a pore-restricted molecular sieve can be used to eliminate more sterically demanding species from the reaction network and can effectively remove these from consideration. In this maimer, one can achieve higher levels of a desired species, such as PX from EB, than could ordinarily be obtained by isomerization over a larger-pore zeolite. 

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