Entropy factors affecting

Harris, J. E., Factors Affecting Polymer-Polymer Miscibility The Relative Importance of Entropy and Enthalpy, Ph.D. Thesis, The University of Texas at Austin, Austin TX, (1981). 

The various factors affecting the entropies of mixing and rotation of the dimethylcyclohexanes are collected in Table 1. For computation of equilibria in such a complex system it is convenient to define an equilibrium constant, as being the ratio of two isomers that differ by only one, gauche interaction. Then for a pair of isomers that differ in energy by n interactions,... 

Physical 18 marks Molecular Hydrogen Chemical equilibrium constant calculations and its qualitative interpretation, equilibrium compositions and factors affecting these compositions, use of C, enthalpy and entropy data for equilibrium constant calculation at different temperatures... 

The ionic liquid structure, determining viscosity, cohesive pressure and degree of order, therefore, seems to be the main factor affecting the rate of diffusion-controlled reactions, influencing both the enthalpy and the entropy of the process. 

Each connects q to the macroscopic quantities of either volume or entropy. A newer approach considers factors affecting the kinetics of the transformation. There are... 

The main advantage of this approach is that it accounts for entropy factors and other essential parameters affecting solubility. The disadvantages are more numerous, such as lack of physical meaning of some parameters, great number of variables, and insufficient coordination between factors influencing solubility that have reduced this approach to an approximate empirical scheme. 

Nevertheless, Nagai s approach raised objections [54-57]. Later, however, Nagai presented proof [58] that his expression, our Eq. (67), is superior to the Rd expression derived from the ART approaeh. Using the hard hexagon adsorption model, Nagai showed that the ART approach underestimates the role of entropy changes as a factor affecting the kinetics of adsorption/desorption processes. 

The polar effects of most m(a and para substituents on the second-order rates of hydrolysis of aromatic esters have demonstrated the marked influence on the energy of activation with little affect to the entropy term. In contrast, ortho substituents alter both the activation energy and the entropy factor. As a general rule, the alkaline hydrolysis of aromatic carboxylic esters is accelerated by substituents with —I, —R effects and is retarded by substituents with +/, +R effects. 

This trend was found to be caused by the nearest neighboring units, and to be independent of remote units. The hypochromicity values for the 1/1 mixture of adenine and thymine derivatives are tabulated in Table 1. The results suggest the affect of the molecular weight dependency of the intermolecular interaction. It can be seen from the Table that the interaction between the oligomers is fairly small, while interaction between the oligomers and the polymer are remarkable. The polymer effect observed for the intermolecular interaction may be caused by an entropy factor, because the polymer has a number of nucleic acid bases in one molecular chain as the interaction sites. 

V. negative entropy factor or hydrophobic effect which, together with London-van der Waals forces (i) make up the so-called hydro-phobic bonds between lipid chains since this effect would also partly contribute to the conformation of the protein, it would affect cohesion of the whole unit. 

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