Apparent molar quantities of sodium octanoate in aqueous solutions

Densities and sound velocities of aqueous solutions of sodium octanoate were determined in a range of molalities between 0.0352 and 0.8105 mol kg–1 at 25, 30, 35, 40 and 45 °C. The isotherms of molality dependence of both density and sound velocity were used to determine the cmcs. Apparent molar volumes and compressibilities were determined from measurements of ultrasound velocity and density. The values of apparent molar volumes and compressibilities at infinite dilution and the apparent molar quantities in the micellar range were obtained and studied as a function of temperature. Values of the critical micelle concentration and the apparent molar quantities in the premicellar and postmicellar range are discussed and compared with the values of the corresponding fluorinated compound.