The Compressibilities and Thermal Pressure Coefficients of Certain Liquids

Values for the compressibilities of heptane, acetone, carbon tetrachloride, benzene, carbon disulfide, ethylene chloride, ethylene bromide and bromoform, obtained by Westwater, Frantz and Hildebrand from their direct measurements of the thermal pressure coefficient, ${\left(\frac{\partial p}{\partial T}\right)}_v$, were subject to a small error which is here corrected. The corrected values are compared with some recalculated from the adiabatic compressibilities directly measured in 1913 by Tyrer, and obtained recently by Freyer, Hubbard and Andrews by the aid of a sonic interferometer. The data from the three sources and methods show excellent agreement. Values are given for the constant $v^{2}T{\left(\frac{\partial p}{\partial T}\right)}_v$, from which can be calculated the coefficients of thermal pressure or of compressibility at various temperatures by the aid of existing data for the densities and coefficients of expansion. In the following list the first number for each substance represents the coefficient of thermal pressure at 20°, the second the compressibility at 20°×${10}^7$ and the third the value of the above mentioned constant: Heptane, 8.66, 1430, 5420; acetone, 11.32, 1260, 5305; carbon tetrachloride 11.47, 1060, 1325; benzene, 12.58, 966, 4800; carbon disulfide, 12.67, 938, 2340; ethylene bromide, 15.20, 633, 936; ethylene chloride, 14.17, 818, 2640; bromoform, 15.32, 594, 537. The unit of pressure is the atmosphere, $v$ is the specific volume.