LAUSR

Abstract The densities and sound velocities at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K were measured for aqueous solutions of glycine, trimethylamine-N-oxide, taurine and N-methylacetamide. From these data, the apparent molar volumes, VΦ, the apparent molar isentropic compressions, KS,Φ, and the Passynski hydration numbers of solutes were determined. The concentration dependencies of the calculated quantities, their limiting values and temperature characteristics are discussed in terms of solute-solvent and solute-solute interactions. The obtained data clearly show strong hydration of the molecules of glycine, trimethylamine-N-oxide and taurine. Opposite effect, i.e. weak interactions with water molecules, is found for N-methylacetamide.