Surface Properties and Molar Volumes of Acetone–Ethanol Solutions

Experimental data are presented on the surface tension and density of acetone (chemically pure) and ethanol (pure for analysis) and acetone–ethanol solutions of different concentrations. The temperature dependence of density is measured with a VIP-2MR vibration density meter with a systemic error of ±0.01 g/cm3. Surface tension (ST) is measured with hanging drops on a DSA-100 KRUSS tensiometer whose systemic error is no more than 1%. Experimental measurements show the concentration dependences of molar volumes and surface tension within the experimental error are described by a linear function. Calculations of the ST isotherms according to the equation of A.A. Zhukhovitsky, obtained by assuming the surface layer and bulk phase are ideal, show the theoretical ST isotherms coincide with experimental ones within the experimental error. Calculations of the thermodynamic parameters of the surface layer show the coefficients of thermodynamic activities of the components in the surface layer are close to unity throughout the range of concentrations. Based on these results and the finite thickness of layers, it is concluded that the surface layers of ethanol–acetone solutions is ideal.