Ultrasonic speed in compressed liquid by a sing-around method

Abstract A new apparatus for the measurement of ultrasonic speed in compressed liquid was constructed. The reliability of this instrument was confirmed by measuring the speeds in pure benzene in the ranges from 283.15 to 323.15 K and pressures up to near freezing pressure, and by comparing the results with literature values. The isentropic compressibilities κ S were also determined using the experimental speeds and densities, and the results κ S ( u ) were compared with those observed directly elsewhere κ S (d) and those calculated thermodynamically κ S (c) from ( p , V m , T ). At atmospheric pressure, the present results, while agreeing with κ S ( u ) reported in the literature, show differences from κ S (d) and κ S (c), while those for higher pressures close on a simple curve with κ S (c).