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.

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.

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.

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

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%.

Estimation of heats of vaporization for non associating organic liquids from the boiling points at various pressures

1986 ◽  
Vol 64 (4) ◽  
pp. 635-640 ◽  
Author(s):  
J. Peter Guthrie
Keyword(s):  
Heat Capacity ◽  
Vapor Pressure ◽  
Boiling Point ◽  
Room Temperature ◽  
Quadratic Function ◽  
Organic Liquids ◽  
Heat Of Vaporization ◽  
Boiling Points ◽  
Temperature And Pressure ◽  
Heats Of Vaporization

At any pressure the heat of vaporization can be expressed as a quadratic function of the boiling point at that pressure. A seven parameter equation expressing the simultaneous dependence on boiling point and pressure can be fitted to the data; six pressures from 1 to 760 Torr (1 Torr = 133.3 Pa) were used. ΔHvap = b11 + b12 In (p) + b13p + (b21 + b22 In (p))tbp + (b31 + b32 In (p))tbp2. This relationship served as a guide for developing a relationship between vapour pressure at 25 °C and the calorimetric heat of vaporization, and also a relationship between vapor pressure at 25 °C and the boiling point at some other pressure. Parameters for both these relationships could be derived from the parameters obtained for ΔHvap as a function of temperature and pressure. A third method was developed starting from an equation for vapor pressure and fitting to the heat of vaporization, the heat capacity of vaporization, and at least one t,p point. These methods allow the estimation of the vapor pressure at room temperature from very meager data. The problems of errors in estimated values are discussed.

Sign in / Sign up

Export Citation Format

Share Document