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.

Heat Capacity of K3LnCl6 Compounds with Ln = La, Ce, Pr, Nd

1999 ◽  
Vol 54 (3-4) ◽  
pp. 229-235 ◽  
Author(s):  
M. Gaune-Escard ◽  
L. Rycerz
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Phase Transitions ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Heat Capacities ◽  
Scanning Calorimetry ◽  
The Enthalpy Of Formation

The heat capacities of the solid and liquid K3LnCl6 compounds (Ln = La, Ce, Pr, Nd) have been determined by differential scanning calorimetry (DSC) in the temperature range 300 -1100 K. Their temperature dependence is discussed in terms of the phase transitions of these compounds as reported in literature. The heat capacity increases and decreases strongly in the vicinity of a phase transition but else varies smoothly. The Cp data were fitted by an equation which provides a satisfactory representation up to the temperatures of Cp discontinuity. The measured heat capacities were checked for consistency by calculating the enthalpy of formation of the liquid phase, which had been previously measured. The results obtained compare satisfactorily with these experimental data.

Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

1988 ◽  
Vol 53 (12) ◽  
pp. 3072-3079
Author(s):  
Mojmír Skokánek ◽  
Ivo Sláma
Keyword(s):  
Heat Capacity ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Dimethyl Sulfoxide ◽  
Liquidus Temperature ◽  
Molar Heat Capacity ◽  
Solid Phase ◽  
Zinc Nitrate ◽  
Heat Capacities ◽  
Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

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

Electronic heat capacity of some vanadium compounds at low temperatures

2021 ◽  
pp. 8-12
Author(s):  
Vad.I. Surikov ◽  
◽  
Val.I. Surikov ◽  
Y.V. Kuznetsova ◽  
N.A. Semenyuk ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Density Of States ◽  
Low Temperatures ◽  
Molar Heat Capacity ◽  
Constant Pressure ◽  
State Density ◽  
Electronic Heat Capacity ◽  
Vanadium Compounds ◽  
Electronic Heat

The paper presents the results of a study of the temperature dependence of molar heat capacity at constant pressure in the range (from 5 to 300 K) for vanadium-based materials. For all the studied materials, the values of the density of States near the Fermi level are calculated. It was found that for V3Si and V3Ge materials, the values of the state density μ( E ) correlate with the transition temperatures to the superconducting state. For materials V2O3 and V1.973Me0.027O3 (Me - Al, Fe, Cr), it was found that the temperatures of metal-dielectric phase transitions decrease with increasing values of the density of States.

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.

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.

Heat capacities of 4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone, 1-hexanol, 1-heptanol, and 1-octanol in the temperature range 298-318 K

1989 ◽  
Vol 54 (3) ◽  
pp. 602-607 ◽  
Author(s):  
František Veselý ◽  
Petr Barcal ◽  
Milan Zábranský ◽  
Václav Svoboda
Keyword(s):  
Heat Capacity ◽  
Liquid State ◽  
Constant Pressure ◽  
Heat Capacities ◽  
Temperature Range ◽  
Selection Of

Molar heat capacities of 4-methyl-2-pentanone and 2,6-dimethyl-4-heptanone in the liquid state have been measured at a constant pressure over the temperature range 298.15 to 318.15 K. In order that the appropriateness of selection of literature data for correlation of the heat capacity as a function of temperature may be verified, results for three 1-alkanols (1-hexanol, 1-heptanol, and 1-octanol) have been measured over the same temperature range.

Quadratic temperature dependence of electronic heat capacities in the κ-type organic superconductors

2016 ◽  
Vol 30 (13) ◽  
pp. 1642014 ◽  
Author(s):  
Shusaku Imajo ◽  
Satoshi Yamashita ◽  
Hiroki Akutsu ◽  
Yasuhiro Nakazawa
Keyword(s):  
Heat Capacity ◽  
Temperature Dependence ◽  
Heat Capacities ◽  
Organic Superconductors ◽  
Pairing Symmetry ◽  
Electronic Heat Capacity ◽  
Text Type ◽  
Electronic Heat ◽  
Normal States ◽  
Quadratic Temperature

We carried out a systematic measurement and data analysis of low-temperature heat capacities of three BEDT-TTF-based superconductive compounds with [Formula: see text]-type structure, where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene so as to compare the character of the quasi-particle excitations reflected in the electronic heat capacity. We used an original relaxation calorimetry cell with much reduced addenda heat capacity as compared with previous works. The three compounds, [Formula: see text]-(BEDT-TTF)2Cu(NCS)2, [Formula: see text]-(BEDT-TTF)2Ag(CN)2H2O, [Formula: see text]-(BEDT-TTF)4Hg[Formula: see text]Br8 show distinct quadratic temperature dependence in their electronic heat capacity obtained by subtracting normal states data obtained by applying magnetic fields from the 0 T data. The line-nodal gap due to [Formula: see text]-wave pairing symmetry is suggested as common phenomena of the superconductivity of the [Formula: see text]-type compounds.

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