J. Phys. IV France
Volume 117, October 2004
Page(s) 73 - 78

J. Phys. IV France 117 (2004) 73-78

DOI: 10.1051/jp4:2004117011

Investigation of nonelectrolytic liquids dissolved in water by photoacoustic and acoustic methods. The case of ethyl alcohol

A. Sikorska and B.B.J. Linde

University of Gdansk, 80-952 Gdansk, Poland

Thermal effusivity, e, of water solutions of ethyl alcohol has been determined at the room temperature by means of photoacoustic (PA) method versus alcohol concentration. The velocity of ultrasound (v) and the density ( $\rho$) have been measured in the temperature range from 288.15 to 328.15 K. Based on the data obtained, the adiabatic compressibility coefficient $\beta$ has been calculated from Laplace's equation $\beta=(\rho\,\rm v^2)^{-0.5}$ The variations of $\beta$ with concentration ( $\mu$: mole fraction) and temperature have been studied. The compressibility isotherms plotted versus mole fraction of ethyl alcohol intersect approximately at a common point ( $\mu_S$) before reaching minimum values. Structural interactions and formation of a compact pseudo-stable structure in the region of a very low ethyl alcohol concentration have been suggested based on the results of the thermal effusivity and adiabatic compressibility determination.

© EDP Sciences 2004