The properties of binary mixtures of tetramethylmethane, tetramethylsilane, and tetramethylstannane I. Excess enthalpies and excess volumes

Abstract

The excess molar enthalpy H m E and excess molar volume V m E have been measured as a function of mole fraction at about 283 K for each of the binary liquid mixtures formed from tetramethylmethane, tetramethylsilane, and tetramethylstannane. For tetramethylmethane + tetramethylsilane H m E and V m E are both positive; for the other two mixtures H m E is positive while V m E is negative. Comparison of the results with theories depending on the assumption of the principle of corresponding states is deferred until the results of measurements of G m E and measurements of the critical quantities have been presented. Some of the isothermal-jacket-calorimetric measurements of H m E reported were made by deliberately arranging for a fairly high Newtonian cooling coefficient k and measuring the curve of temperature against time until the temperature had returned to that of the surroundings, so as to avoid the uncertain extrapolations inherent in measurements made with a low, but seldom low enough, value of k; the method is briefly described.