Molar Heat Capacity and Isothermal Compressibility of Binary Liquid Mixtures: Carbon Tetrachloride + Benzene, Carbon Tetrachloride + Cylohexane and Benzene + Cylohexane

Abstract

The molar heat capacity at constant pressure Cp, for the three binary liquid mixtures carbon tetrachloride + benzene, carbon tetrachloride + cyclohexane, and benzene + cyclohexane was determined at 298.15 K from measurements of the volumetric heat capacity Cp/V in a Picker flow microcalorimeter (V is the molar volume). For the molar excess heat capacity CpE, the precision of the adopted stepwise procedure is characterized by a standard deviation of ±0.03 JK‐1mol‐1 or smaller (which is less than 2% of the maximal ∣CPE∣ ). The use of these three systems as test mixtures for measurements of CPE, “of binary nonelectrolyte systems is recommended. ‐Auxiliary data from the literature on ultrasonic velocities, molar volumes and thermal expansivities were used to calculate the molar heat capacity at constant volume Cv, and the isothermal compressibility βT of the pure substances, as well as the corresponding excess quantities CvE and (VβT)E of the binary systems. A discussion of our results in terms of external rotational behavior of the molecules is presented.

Densities, Viscosities, Refractive Indices, and Heat Capacities of Poly(propylene glycols) or Poly(ethylene glycol)−Poly(propylene glycol)−Poly(ethylene glycol)-block-Copolymers + 2-Methyltetrahydrofuran at (298.15 and 313.15) K and at Atmospheric Pressure

“…17,18 The uncertainty in the densities was ( 1.5 · 10 -5 g · cm -3 at 308.15 K. Correspondingly, the uncertainty in the volume variation ∆V is estimated as < 1 %. Before measurements, the apparatus was checked by determining the ∆V using the test mixture benzene + cyclohexane at 298.15 K. Agreement of our results with those of the literature 19 is within 1 %.…”

Thermodynamics of mixtures involving some (benzene derivatives+benzonitrile)

“…Experimental densimetric and calorimetric techniques have been described in detail in previous works [19][20][21][22][23]. Densities, q, of pure components and their mixtures were measured with Picker densimeters (models 02D and 03DCss, SODEV, Canada), operated under flow conditions.…”

“…Volumetric heat capacities were determined using the stepwise procedure [19,20,23] with a Picker flow microcalorimeter (from Setaram) equipped with gold cells, the flow rate being 0.01 cm 3 AE s À1 . The stability of the thermostat was greater than 0.005 K, and the apparatus was adjusted to obtain a centered temperature of 298.15 K accounting for the increment of temperature imposed by the measuring process.…”

CHAPTER 7. Excess Volumes of Liquid Nonelectrolyte Mixtures

“…zero density. 159 Once the constant B is determined, one may obtain density differences r L À r L* ref of any solution with density r L relative to that of pure water with density r L* ref from…”