Dissociation composition, degree

Using the defined dependence on TaF5 concentration of the degree of dissociation P the molecular composition of the melt was calculated and is presented in Fig. 65. 

Reactivity ratios for the copolymerization of AN and DM WS in DMSO were found to be rj =0,53 and r2=0,036, and in water r1=0,56 and r2=0,25. The higher reactivity of DM VPS in the copolymerization with AN in aqueous medium, as compared with its reactivity in DMSO, can be explained by a higher degree of dissociation of DMVPS in aqueous medium. This fact also produces a considerable effect on the character of the distribution of monomeric units within the copolymers, which manifests itself in the change of their solubility in water. Copolymers containing 30% of monomeric units AN obtained from a 90 10 mixture of AN and DMVPS in DMSO, irrespective of the level of conversion, are completely soluble in water, whereas copolymers of the same composition, but obtained in aqueous medium with a yield 40%, are insoluble in water. 

In the simplest situation where a solution of a weak acid is used the degree of dissociation of the acid and hence the composition of the solution will depend on the pH of the solution. If, as is often the case, a complexing agent is itself a weak acid, its complexing reactions will also be pH dependent. 

However the question of whether the salt should be considered as a molecular or ionic constituent is raised. The laws of solution theory suggest the latter. Hence, unless the salt is either fully associated or fully dissociated over the entire liquid composition range, the varying degree of salt dissociation over this range is important. In other words, since both species of ion and salt molecules contribute to the total effect caused by a partially dissociated salt, the total number of salt particles (ions and molecules) present should be considered. This would suggest that an even more correct expression of liquid composition for use in calculating liquid phase activity coefficients would be... 

In summary, to be thermodynamically rigorous, the salt presence must be recognized in calculating activity coefficients for use in correlating equations its degree of dissociation as a function of liquid composition, among other factors, must be considered also. Conversely, it may be possible to apply data that are believed to be consistent to a consistency test in order to calculate degree of dissociation as a function of liquid composition. 

It is evident from these two examples, that the chemistry of low pressure plasmas is fundamentally different from the chemistry of ordinary systems. Unfortunately, the actual chemical composition of these plasmas is not known in most cases. The high degree of dissociation indicates that only simple (diatomic ) species which are generated by fast reactions on the walls of the discharge tube may survive in the plasma. This fact has to be kept in mind in any theoretical consideration of chemical processes taking place in such systems. 

In the preceding discussion the reaction has been represented as involving undissociated Cu(OAc)2 molecules rather than simple cupric ions or other cupric complexes. This appears to be consistent with the kinetic results taken in conjunction with independent measurements of the dissociation constants of cupric acetate. These measurements indicate that in solutions of the composition used in these experiments, cupric acetate is predominantly undissociated. The degree of dissociation to CuOAc+ ranges from about 10% at the highest NaOAc (used as a buffer) concen-... 

The degree of induction of the dissociation of PMAA in the presence of various polycations is estimated by its apparent dissociation constant (pKJ calculated from the potentiometric titration results as shown in Fig. 6, using the Henderson-Hasselbach equation (see Table 5). In the presence of polycations, pKa and one of the interaction parameters relative to adjacent ionic sites, n, decreases. This confirms the induction of dissociation. Furthermore, the difference in the composition of the polyelectrolyte complex composed of one kind of polycation and different poly(carboxylic acid)s, may be affected by pKa and the conformation of them. 

In the system of a weak polyaeid and a weak polybase, whose degrees of dissociation depend on the pH of the solution, the composition of the obtained complex is as follows ... 

Figure 2. Variation of the degree of dissociation of ionic micelles with solvent composition. ( ), Data from emf measurements, (O, O), conductance 4 mobility measurements. D = decyl, DO = dodecyl.

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