Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5413002 | Journal of Molecular Liquids | 2010 | 6 Pages |
Abstract
Density (Ï) and ultrasonic velocity (u) values of glycine in 1.0 M aqueous KCl and 1.0 M aqueous NaCl solutions have been measured as a function of amino acids concentration at T = (298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K. Using the Ï and u data, the thermodynamic parameters such as partial molal volume (Ï0v), isentropic compressibility (κs), change in isentropic compressibility (Îκs), relative change (Îκs/κ0) in isentropic compressibility and partial molal isentropic compressibility (Ï0k), values have been computed. The increase in partial molal volume with temperature is attributed to the volume expansion of hydrated zwitterions. The Ï0v and Ï0k values of glycine in 1.0 M aqueous KCl and NaCl solutions are larger than the corresponding values in water. The larger partial molal volumes of glycine in 1.0 M aqueous KCl and NaCl is ascribed to the formation of 'zwitterion-K+/Na+/Clâ' and 'K+/Na+/Clâ-water dipole' aggregates in solutions. The variation of κs, Îκs and Îκs/κ0 with amino acid/zwitterions concentration and temperature is discussed in terms of zwitterions-ions, zwitterions-water dipoles, ion-ion, ion-water dipoles due to intermolecular/interionic interactions occurring in the systems.
Related Topics
Physical Sciences and Engineering
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Physical and Theoretical Chemistry
Authors
Riyazuddeen Riyazuddeen, Imran Khan,