Calculation of the difference between molar heat capacity of liquid and ideal gas from the temperature dependence of heat of vaporization

1979 ◽  
Vol 44 (6) ◽  
pp. 1687-1697 ◽  
Author(s):  
Vladimír Majer ◽  
Václav Svoboda ◽  
Jiří Pick
Keyword(s):  
Heat Capacity ◽  
Temperature Dependence ◽  
Molar Heat Capacity ◽  
A Priori ◽  
Maximum Error ◽  
Ideal Gas ◽  
Saturated Hydrocarbons ◽  
Heat Of Vaporization ◽  
The Difference ◽  
Experimental Values

A method was developed for calculating the difference ΔcP between molar heat capacity of liquid cP1 and of ideal gas cPgo from the temperature dependence of heat of vaporization. By an a priori analysis the maximum error of the calculation procedure was determined. The exploitation of the method was demonstrated on a group of 20 saturated hydrocarbons. Besides these ΔcP values, the data on cP1 and cPgo were calculated in the regions where no experimental data are available, by combining ΔcP with the experimental values of molar heat capacities.

Verification of the calculation of the constant-volume heat capacity difference of substances in the liquid and gas phases from the temperature dependence of heat of vaporization

1983 ◽  
Vol 48 (8) ◽  
pp. 2141-2146
Author(s):  
Věra Uchytilová ◽  
Václav Svoboda
Keyword(s):  
Heat Capacity ◽  
Temperature Dependence ◽  
Constant Volume ◽  
Heat Of Vaporization ◽  
Gas Phases ◽  
Volume Heat ◽  
Pure Substances ◽  
The Difference ◽  
Heats Of Vaporization ◽  
The Ideal

The possibilities were verified of the proposed method for calculating the difference between constant-volume heat capacities of liquids and gases in the ideal state from known data on the volumetric behaviour and temperature dependence of heats of vaporization of pure substances.

Evaluation of Low-Temperature Properties and the Fragility of Asphalt Binders with Non-Arrhenius Viscosity–Temperature Dependence

2005 ◽  
Vol 1901 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Huachun Zhai ◽  
Delmar Salomon
Keyword(s):  
Temperature Dependence ◽  
Asphalt Binders ◽  
Arrhenius Behavior ◽  
Direct Tension ◽  
Different Temperatures ◽  
Rotational Viscosity ◽  
Liquid Fragility ◽  
The Difference ◽  
Critical Cracking Temperature ◽  
Experimental Values

Rotational viscosities of different asphalt binders were determined at temperatures between 80°C and 185°C. Viscosity–temperature dependence of asphalt binders was described with the use of the Vogel–Tammann–Fulcher (VTF) and the William–Landel–Ferry (WLF) equations. The Vogel temperature ( Tv) and the glass transition temperature ( Tg) for different asphalt binders were determined by fitting experimental values of viscosity at different temperatures with these two equations. For asphalt binders, the difference between Tv and Tg was about 40K. Effects of asphaltenes, aging, chemical modification, and polymer content on these temperatures were evaluated. As asphaltene content increased, both temperatures, Tv and Tg, increased. Different polymers showed different effects on these temperatures. The values of Tv and Tg were correlated with the critical cracking temperature ( Tcr) determined through use of a bending beam rheometer and a direct tension tester. The results suggested that the correlations between Tv, Tg, and Tcr could be used to determine Tcr from the rotational viscosity results tested at high temperature. With simple rotational measurements, a quick estimation of Tcr of asphalt binders could be obtained. Liquid fragility theory was also used to study Tg of asphalt binders. Parameters determined with the VTF and WLF equations indicated that asphalt binders behaved as fragile liquids because of their non-Arrhenius behavior in the temperature range studied.

scholarly journals SYNTHESIS AND STUDY OF THERMODYNAMIC PROPERTIES OF NEW ZINCATE-MANGANITES NdM2IIZnMnO6 (MII − Mg, Ca)

2018 ◽  
Vol 61 (3) ◽  
pp. 16
Author(s):  
Bulat К. Kasenov ◽  
Shuga B. Kasenova ◽  
Zhenisgul I. Sagintaeva ◽  
Yerbolat Y. Kuanyshbekov ◽  
Meruert O. Turtubaeva
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Thermodynamic Properties ◽  
Temperature Dependence ◽  
Ceramic Technology ◽  
Cell Parameters ◽  
Dynamic Calorimetry ◽  
Temperature Dependences ◽  
Calorimetric Studies ◽  
Experimental Values

Zincate-manganites with the composition NdM2IIZnMnO6 (MII− Mg, Ca) were synthesized using ceramic technology from oxides of Nd (III), Zn (II), Mn (III) and carbonates of alkaline-earth metals - magnesium and calcium. X-ray patterns of the prepared substancies were measured on a DRON-2.0 diffractometer. We established that they crystallize in the cubic system with the following unit cell parameters: NdMg2ZnMnO6 – а=13.927±0.035 Å, Z = 4, V0 = 2701.36±0.11 Å3, V0el.cell. = 675.34±0.03 Å3, ρX-ray = 4.20, ρpycn. = 4.19±0.01 g/cm3; NdCa2ZnMnO6 – а=13.910±0.030 Å, Z = 4, V0 = 2691.45±0.10 Å3, V0el.cell. = 672.86±0.03 Å3, ρX-ray = 4.04, ρpycn. = 4.01±0.08 g/сm3. The temperature dependence of the heat capacity of NdMg2ZnMnO6 and NdCa2ZnMnO6 was studied by dynamic calorimetry in the range of 298.15-673 K on the IT-S-400 calorimeter. Five parallel experiments were performed at each temperature point with 25 K step. The results were averaged and analyzed using mathematical statistics. As a result of calorimetric studies of the heat capacity, within the temperature range of 298.15-673 K, we discovered on the curves of the temperature dependence of heat capacity the phase transitions of the II kind at the following temperatures: 373, 548 К- NdMg2ZnMnO6, 448, 573 К – NdCa2ZnMnO6. These phase transitions were probably due to Schottky effects -the transition from semiconductivity to metallic conductivity, and variations in capacity, dielectric permittivity, the occurrence of Curie or Neel points. The equations of the temperature dependence of the heat capacity were derived on the basis of the experimental values with account the temperatures of the phase transitions. By the ion increment method, we calculated the standard entropies of the compounds investigated. We calculated the temperature dependences of С°р(Т) and thermodynamic functions Н°(Т)-Н°(298.15), S°(T) and Фхх(Т).Forcitation:Kasenov B.K., Kasenova Sh.B., Sagintaeva Zh.I., Kuanyshbekov Е.Е., Turtubaeva М.О. Synthesis and study of thermodynamic properties of new zincate-manganites NdM2IIZnMnO6 (MII − Mg, Ca). Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 3. P. 16-20

scholarly journals THERMOPHYSICAL PROPERTIES OF ALLOY COMPOSITIONS (2Bi2O3∙B2O3)100-x(2Bi2O3∙3GeO2)x (x=0, 10, 50)

2021 ◽  
pp. 44-48
Author(s):  
S.I. Bananyarli ◽  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Phase Transitions ◽  
Thermal Resistance ◽  
Temperature Dependence ◽  
Thermophysical Properties ◽  
Chemical Bonds ◽  
Temperature Range ◽  
The Difference

The termophisical properties, namely, the temperature dependence of thermal conductivity, thermal resistance and heat capacity of the allays compositions (2Bi2O3∙B2O3)100-x (2Bi2O3∙3GeO2)x in the (300–600) K temperature range have ligated been invest. An increase in thermal conductivity χ(T) above 500 K is probably associated with the softening of alloys and the presence of blurred phase transitions, which are accompanied by partial breaking of chemical bonds. It was revealed that the heat capacity in alloys of the compositions (2Bi2O3∙B2O3)100-x (2Bi2O3∙3GeO2)x increases with an increase in the GeO2 concentration. In the studied samples, that showed their own disorder during solidification, the thermal conductivity is strongly reduced due to the enhancement of the anharmonicity of phonon – phonon interactions. İn turn a small "disorder" introduced by defects due to the difference in masses is not noticeable against the background of the huge "disorder" inherent in oxide substances

Relation of the temperature derivative of heat of vaporization to the difference of heat capacities along the saturated vapour pressure curve

1981 ◽  
Vol 46 (10) ◽  
pp. 2446-2454
Author(s):  
Václav Svoboda ◽  
Zdeněk Wagner ◽  
Petr Voňka ◽  
Jiří Pick
Keyword(s):  
Heat Capacity ◽  
Vapour Pressure ◽  
Pressure Curve ◽  
Temperature Derivative ◽  
Heat Of Vaporization ◽  
Saturated Vapour Pressure ◽  
Saturated Vapour ◽  
Vapour Pressure Curve ◽  
Pure Substances ◽  
The Difference

A method of calculating the heat capacity difference of liquid and its vapour along saturated vapour pressure curve is discussed. The qualitative course of this difference in dependence on temperature obtained from the data on the temperature dependence of heat of vaporization of pure substances is judged.

Temperature dependence of heats of vaporization of saturated hydrocarbons C5-C8; Experimental data and an estimation method

1979 ◽  
Vol 44 (3) ◽  
pp. 637-651 ◽  
Author(s):  
Vladimír Majer ◽  
Václav Svoboda ◽  
Slavoj Hála ◽  
Jiří Pick
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Estimation Method ◽  
Saturated Hydrocarbons ◽  
Heat Of Vaporization ◽  
Temperature Range ◽  
Entropy Of Vaporization ◽  
Heats Of Vaporization

Heats of vaporization of a group of 10 alkanes C6-C8 and 2 cycloalkanes were measured in a temperature range of 25-80 °C. By combining the obtained results with selected literature data, a set of very accurate values of heats of vaporization as functions of temperature was made up for 22 saturated C5-C8 hydrocarbons. This set was employed for the verification of the proposed estimation method for the determination of heat of vaporization which is based on the principle of combination of a contribution method with constant entropy-of-vaporization rules. In this way it is then possible to estimate heats of vaporization of C4-C9 alkanes with an error lower than 0.5%.

scholarly journals TEMPERATURE DEPENDENCE OF HEAT CAPACITY SCANDIUM, YTTRIUM, CERIUM, PRASEODYMIUM, NEODYMIUM AND EUROPIUM

InterConf ◽  
2021 ◽  
pp. 549-553
Author(s):  
Z. Nizomov ◽  
R. Saidzoda (Saidov) ◽  
J. Sharipov ◽  
B. Gulov
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Temperature Dependence ◽  
Molar Heat Capacity ◽  
Statistical Criterion

Using the Sigma Plot program, using the available experimental data on the heat capacity of scandium, yttrium, praseodymium, cerium, neodymium, lanthanum, and europium, the equations of the temperature dependence of the specific and molar heat capacity were established. The optimal degrees for the temperature in these equations were determined using the Fisher statistical criterion. It is revealed that the general form of the temperature dependence of the heat capacity for these metals is a four-term polynomial in the form C (T) = a + b T + c T2 + d T3.

Molar heat capacities and enthalpies of fusion for the system zinc chloride-dimethyl sulphoxide

1987 ◽  
Vol 52 (9) ◽  
pp. 2188-2193
Author(s):  
Mojmír Skokánek ◽  
Ivo Sláma
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Zinc Chloride ◽  
Liquid State ◽  
Molar Heat Capacity ◽  
Heat Capacities ◽  
Dimethyl Sulphoxide ◽  
Molten State

Molar heat capacities and molar enthalpies of phase transitions in the system ZnCl2-DMSO have been investigated over the temperature range 240 to 405 K and the concentration range 11.1 to 40 mole % ZnCl2. The temperatures of fusion and of phase transitions were determined and compared with literature data. Equations were proposed for the description of the temperature dependence of the molar heat capacity in the liquid state. The concentration dependence of the molar heat capacity in the molten state was found to exhibit positive deviations from additivity.

scholarly journals Approximating the Temperature–Entropy Saturation Curve of ORC Working Fluids From the Ideal Gas Isobaric Heat Capacity

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3266 ◽  
Author(s):  
Juan A. White ◽  
Santiago Velasco
Keyword(s):  
Heat Capacity ◽  
Molar Heat Capacity ◽  
Approximation Scheme ◽  
Approximate Expression ◽  
Ideal Gas ◽  
Saturation Curve ◽  
Working Fluids ◽  
Organic Rankine Cycles ◽  
Previous Approximation ◽  
The Ideal

Recently, we proposed an approximate expression for the liquid–vapor saturation curves of pure fluids in a temperature–entropy diagram that requires the use of parameters related to the molar heat capacity along the vapor branch of the saturation curve. In the present work, we establish a connection between these parameters and the ideal-gas isobaric molar heat capacity. The resulting new approximation yields good results for most working fluids in Organic Rankine Cycles, improving the previous approximation for very dry fluids. The ideal-gas isobaric molar heat capacity can be obtained from most Thermophysical Properties databases for a very large number of substances for which the present approximation scheme can be applied.

Sign in / Sign up

Export Citation Format

Share Document