Heat Capacity and Thermodynamic Properties of Cesium Pentaborate Tetrahydrate

This paper reports the molar heat capacities of β-CsB5O8·4H2O, which were measured by an accurate adiabatic calorimeter from 298 to 373 K with a heating rate of 0.1 K/min under nitrogen atmosphere. Neither phase transition nor thermal anomalies were observed. The molar heat capacity against temperature was fitted to a polynomial equation of Cp,m (J·mol−1·K−1) = 618.07702 + 39.52669[T − (Tmax + Tmin)/2]/(Tmax − Tmin)/2] − 3.46888[(T − (Tmax + Tmin)/2)/(Tmax − Tmin)/2]2 + 7.9441[(T − (Tmax+ Tmin)/2)/(Tmax − Tmin)/2]3. The relevant thermodynamic functions of enthalpy (HT − H298.15), entropy (ST − S298.15), and Gibbs free energy (GT − G298.15) of cesium pentaborate tetrahydrate from 298 to 375 K of 5 K intervals are also obtained on the basis of relational expression equations between thermodynamic functions and the molar heat capacity.

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Heat Capacity and Thermodynamic Property of Lithium Pentaborate Pentahydrate

Journal of Chemistry ◽

10.1155/2018/7962739 ◽

2018 ◽

Vol 2018 ◽

pp. 1-4 ◽

Cited By ~ 3

Author(s):

Wanjing Cui ◽

Long Li ◽

Yafei Guo ◽

Sisi Zhang ◽

Tianlong Deng

Keyword(s):

Phase Transition ◽

Heat Capacity ◽

Thermodynamic Property ◽

Thermodynamic Functions ◽

Molar Heat Capacity ◽

Adiabatic Calorimeter ◽

Thermal Anomalies

The heat capacity of lithium pentaborate pentahydrate has been measured using an adiabatic calorimeter at the temperature from 297 to 375 K. No phase transition and thermal anomalies were observed. The molar heat capacity of LiB5O8·5H2O can be expressed as Cp,m (J·mol−1·K−1) = 396.79376 + 35.87528 [T-(Tmax+Tmin)/2]/[(Tmax-Tmin)/2] + 0.16494[T-(Tmax+Tmin)/2]/[(Tmax-Tmin)/2]2 + 8.3083[T-(Tmax+Tmin)/2]/[(Tmax-Tmin)/2]3, where T is the temperature in Kelvin, Tmax=375 K, and Tmin=297 K. The thermodynamic functions of (HT-H298.15), (ST-S298.15), and (GT-G298.15) of LiB5O8·5H2O are obtained via the molar heat capacity at the temperature of 5 K intervals.

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Heat Capacity and Thermodynamic Property of Cesium Tetraborate Pentahydrate

Journal of Chemistry ◽

10.1155/2019/9371328 ◽

2019 ◽

Vol 2019 ◽

pp. 1-5 ◽

Cited By ~ 3

Author(s):

Kangrui Sun ◽

Kaiyu Zhao ◽

Long Li ◽

Yafei Guo ◽

Tianlong Deng

Keyword(s):

Phase Transition ◽

Heat Capacity ◽

Free Energy ◽

Water Resources ◽

Thermodynamic Property ◽

Thermodynamic Functions ◽

Molar Heat Capacity ◽

Salt Lake ◽

High Concentration ◽

Thermal Anomalies

In order to recover cesium tetraborate pentahydrate (Cs2O·2B2O3·5H2O) from the high concentration cesium-containing salt lake brines and geothermal water resources, the molar heat capacity of Cs2O·2B2O3·5H2O has been measured with a precision calorimeter at the temperature from 303 to 349 K. It was found that there is no phase transition and thermal anomalies. The molar heat capacity of cesium tetraborate pentahydrate is fitted as Cp,m (J·mol−1·K−1) = 593.85705 + 48.0694[T − (Tmax + Tmin)/2]/(Tmax − Tmin)/2] + 24.86395[(T − (Tmax + Tmin)/2)/(Tmax − Tmin)/2]2 + 0.53077[(T − (Tmax + Tmin)/2)/(Tmax − Tmin)/2]3, and the relevant thermodynamic functions of enthalpy, entropy, and Gibbs free energy of cesium tetraborate pentahydrate are also obtained at intervals of 2 K from 303 to 349 K.

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Heat Capacities and Thermodynamic Properties of Hungchaoite and Mcallisterite

Molecules ◽

10.3390/molecules24244470 ◽

2019 ◽

Vol 24 (24) ◽

pp. 4470

Author(s):

Jiangtao Song ◽

Fei Yuan ◽

Long Li ◽

Yafei Guo ◽

Tianlong Deng

Keyword(s):

Phase Transition ◽

Thermodynamic Properties ◽

Thermodynamic Functions ◽

Process Design ◽

Chemical Engineering ◽

Heat Capacities ◽

Salt Lakes ◽

Engineering Process ◽

Thermal Anomalies ◽

First Time

The heat capacities on two minerals of hungchaoite (MgB4O7·9H2O, Hu) and mcallisterite (MgB6O10·7.5H2O, Mc) have been measured with a precision calorimeter at temperatures ranging from 306.15 to 355.15 K, experimentally. It was found that there are no phase transition and thermal anomalies, and the molar heat capacities against temperature for the minerals of hungchaoite and mcallisterite were fitted as C p , m , Hu = − 27019.23675 + 229.55286 T − 0.63912 T 2 + ( 5.95862 × 10 − 4 ) T 3 and C p , mMc = − 9981.88552 + 84.10964 T − 0.22685 T 2 + ( 2.0593 × 10 − 4 ) T 3 , respectively. The molar heat capacities and thermodynamic functions of (HT-H298.15), (ST-S298.15), and (GT-G298.15) at intervals of 1 K for the two minerals were obtained for the first time. These results are significant in order to understand the thermodynamic properties of those minerals existing in nature salt lakes, as well as applying them to the chemical engineering process design.

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Heat Capacities and Thermodynamic Properties of Pinnoite and Inderite

Journal of Chemistry ◽

10.1155/2020/6181356 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Hanyu Zheng ◽

Kangrui Sun ◽

Long Li ◽

Yafei Guo ◽

Tianlong Deng

Keyword(s):

Free Energy ◽

Phase Transitions ◽

Thermodynamic Properties ◽

Gibbs Free Energy ◽

Thermodynamic Functions ◽

High Purity ◽

Heat Capacities ◽

Thermal Anomalies ◽

Natural Minerals ◽

First Time

In this paper, in order to understand the thermodynamic properties of natural minerals of pinnoite (MgB2O4·3H2O, Pin) and inderite (Mg2B6O11·15H2O, Ind) deposited in salt lakes, heat capacities of two minerals were measured using a precision calorimeter at temperatures from 306.15 to 355.15 K after the high purity was synthesized. It was found that there are no phase transitions and thermal anomalies for the two minerals, and the molar heat capacities against temperature for Pin and Ind were fitted as Cp,m,pin = −2029.47058 + 16.94666T − 0.04396T2 + 3.89409×10−5T3 and Cp,m,Ind = −30814.43795 + 282.68108T − 0.85605T2 + 8.70708×10−4T 3, respectively. On the basis of molar heat capacities (Cp,m) of Pin and Ind, the thermodynamic functions of entropy, enthalpy, and Gibbs free energy at the temperature of 1 K interval for the two minerals were obtained for the first time.

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First and Second-Phase Transitions of Gases at Isobaric Process; Lennard–Jones (9,6) Gases with a Hard Core

Zeitschrift für Naturforschung A ◽

10.5560/zna.2014-0060 ◽

2014 ◽

Vol 69 (12) ◽

pp. 665-672

Author(s):

Akira Matsumoto

Keyword(s):

Phase Transition ◽

Heat Capacity ◽

Free Energy ◽

Critical Point ◽

Thermodynamic Functions ◽

Order Phase Transition ◽

Boiling Point ◽

Hard Core ◽

Lennard Jones ◽

Isobaric Process

AbstractThe thermodynamic functions for Lennard-Jones (9,6) gases with a hard core that are evaluated till the third virial coefficients, are investigated at an isobaric process. Some thermodynamic functions are analytically expressed as functions of intensive variables, temperature, and pressure. Some thermodynamic quantities for carbon dioxide are calculated numerically and drawn graphically. In critical states, the heat capacity diverges to infinity at the critical point while the Gibbs free energy, volume, enthalpy, and entropy are continuous at the critical point. In the coexistence of two phases, the boiling temperatures and the enthalpy changes of vaporization are obtained by numerical calculations for 20 substances. The Gibbs free energy indicates a polygonal line; entropy, volume, and enthalpy jump from the liquid to gaseous phase at the boiling point. The heat capacity does not diverge to infinity but shows a finite discrepancy at boiling point. This suggests that a first-order phase transition at the boiling point and a second-order phase transition may occur at the critical point.

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Thermodynamic Quantities of Square-Well Gases at Isobaric Process

Zeitschrift für Naturforschung A ◽

10.1515/zna-2010-6-712 ◽

2010 ◽

Vol 65 (6-7) ◽

pp. 561-567 ◽

Cited By ~ 1

Author(s):

Akira Matsumoto

Keyword(s):

Phase Transition ◽

Heat Capacity ◽

Free Energy ◽

Critical Point ◽

Thermodynamic Functions ◽

Order Phase Transition ◽

Boiling Point ◽

Thermodynamic Quantities ◽

Square Well ◽

Isobaric Process

The thermodynamic functions for square-well gases evaluated till the third virial coefficient are investigated at an isobaric process. Some thermodynamic functions are analytically expressed as functions of intensive variables, temperature, and pressure. Some thermodynamic quantities for H2O are calculated numerically and drawn graphically. In critical states, the heat capacity, thermal expansivity, and isothermal compressibility diverge to infinity at the critical point while the Gibbs free energy, volume, enthalpy, and entropy are continuous at the critical point. In the coexistence of two phases, the boiling temperatures and the enthalpy changes of vaporization are obtained by numerical calculations for 16 substances. The Gibbs free energy indicates a polygonal line; entropy, volume, and enthalpy jump from the liquid to the gaseous phase at the boiling point. The heat capacity does not diverge to infinity but shows a finite discrepancy at boiling point. This suggests that a first-order phase transition at the boiling point and a second-order phase transition at the critical point may occur.

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The thermodynamics of the divalent metal fluorides. I. Heat capacity of lead tetrafluorostannate, PbSnF4, from 10.3 to 352 K

Canadian Journal of Chemistry ◽

10.1139/v88-093 ◽

1988 ◽

Vol 66 (4) ◽

pp. 549-552 ◽

Cited By ~ 3

Author(s):

Jane E. Callanan ◽

Ron D. Weir ◽

Edgar F. Westrum Jr.

Keyword(s):

Phase Transition ◽

Heat Capacity ◽

Thermodynamic Functions ◽

Adiabatic Calorimetry ◽

Temperature Limit ◽

Divalent Metal ◽

Ion Conductor ◽

Metal Fluorides ◽

Fast Ion Conductor ◽

Fast Ion

We have measured the heat capacity of the fast ion conductor PbSnF4 at 10.3 < T < 352 K by adiabatic calorimetry. Our results show anomalous values in the Cp,m in the region 300 < T < 352 K. These are associated with the α–β crystallographic transition reported at 353 K. Because the upper temperature limit of our cryostat is around 354 K, it was impossible to follow the phase transition to completion. A more subtle anomaly in the Cp,m was detected between 130 and 160 K. Standard molar thermodynamic functions are presented at selected temperatures from 5 to 350 K.

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Electrochemical and thermodynamic properties of U4+ and U3+ on Mo electrode in LiCl-KCl eutectic

Radiochimica Acta ◽

10.1515/ract-2017-2898 ◽

2019 ◽

Vol 107 (2) ◽

pp. 95-104

Author(s):

Ru-Shan Lin ◽

You-Qun Wang ◽

Zhao-Kai Meng ◽

Hui Chen ◽

Yan-Hong Jia ◽

...

Keyword(s):

Free Energy ◽

Thermodynamic Properties ◽

Thermodynamic Functions ◽

Electrochemical Behavior ◽

Diffusion Coefficients ◽

Electrochemical Techniques ◽

Reduction Process ◽

Standard Potential ◽

Hcl Gas ◽

Thermodynamic Functions Of Formation

Abstract In this study, UCl4 was prepared by the reaction of HCl gas with UO2 in the LiCl-KCl eutectic. Then, the electrochemical behavior of U4+ and U3+ on a Mo cathode was investigated by various electrochemical techniques. The reduction process of U4+ was regarded as two steps: U4++e=U3+; U3++3e=U. Diffusion coefficients of U4+ and U3+, the apparent standard potential of U4+/U3+, U3+/U as well as U4+/U in the LiCl-KCl molten salt on the Mo electrode was determined by numerous electrochemical methods. The thermodynamic functions of formation of Gibbs free energy of UCl4 and UCl3 are calculated as well.

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