Effect of temperature on compressibility properties of 0.1, 0.5 and 1.0 molal solutions of alkali metal nitrates. Part 2. Aqueous solutions of lithium nitrate, sodium nitrate and potassium nitrate in the 278.15 K to 353.15 K temperature range

Abstract

Sound velocities in aqueous solutions of LiNO3, NaNO3 and KNO3 were measured at 1K intervals from T=(278.15 to 353.15)K, in the 0.1mol·kg−1 0.5mol·kg−1 and 1.0mol·kg−1 solutions. Determined sound velocities and densities served to determine the isentropic and isothermal compressibilities, the apparent molar compressibilities, the apparent molar volumes, the isochoric thermal pressure coefficients, cubic expansion coefficients, changes of heat capacities with volume and with pressure, and the hydration numbers. In addition were evaluated the ultrasonic relaxation times and corresponding thermodynamic functions of the activation of the viscous process. Determined parameters are qualitatively correlated with changes in the structure of water when alkali metal nitrates are dissolved in it.