The thermodynamic parameter for solvation of some salts of divalent cations and their complexes in different solvents

Abstract

The thesis consists of three chapters besides Arabic and English summary. Chapter one is about general introduction to nano materials, their properties, methods of preparation, properties of used materials in the thesis, solvation, ion solvation, solubility, factors affecting solubility, applications of conductivity, densities and volumes. Also this chapter contains some literature survey of published paper in the area of the thesis.

Chapter two is the experimental part, explains the chemical used and their properties, instruments used for measurements like X-ray diffraction, transmittion electron microscopy, infra-red spectra photometer (FTIR), conductivity bridge and preparation of nano-barium carbonate, nano-copper carbonate and nano-zinc carbonate. Also the preparation of solutions and conductivity measurements are also given in this chapter.

Chapter three is the results and discussion. It divides into three parts. Part one is about, solubility, density and conductivity measurements for nano-barium carbonate in mixed DMF – H2O solvents ( 50, 60, 70, 80, 90 and 100 % ) by volume at four temperatures ( 292.15, 303.15, 308.15 and 313.15K ).

The solubility parameters, molar solubility, activity coefficient, solubility product and dissolution free energy for nano-BaCO3 were evaluated from solubility measurements and it was found that all increased by the increase in both the mole fraction of DMF in the mixtures and temperature due to more salt – solvent interactions.

All types of volumes calculated from densities measurements for nano BaCO3 in mixed DMF – H2O solvents were evaluated from density measurements which are, molar volumes (VM), Van der Waals volume (VW), and electrostriction volume (Ve). All volumes for nano-BaCO3 are increased by the increase in both temperature and proportion of DMF favouring more solvation.

From conductivity measurements and from the relation between molar conductance and (C1/2), the association thermodynamic parameters for nano-BaCO3 alone were evaluated and include the association constant, degree of dissociation, association free energy, enthalpy of association and entropy of association at different temperatures and in mixed DMF – H2O solvents. The association parameters obtained for nano-BaCO3 alone are increased by the increase of both mole fraction of DMF and temperature.