Search Results
A low-temperature heat capacity study of natural lithium micas
Heat capacity of zinnwaldite
functions of zinnwaldite in the same temperature range and its calorimetric entropy at 298.15 K. Furthermore, heat capacity and thermodynamic functions at 298.15 K for zinnwaldite of ideal composition KLiFeAl 2 Si 3 O 10 F 2 have been estimated
of thermodynamic property for this substance is necessary. In this study, the low-temperature heat capacities of this compound over the temperature range from 78 to 350 K were measured by an automated adiabatic calorimeter. The thermodynamic functions
the study in detail. In this article, we report the phase diagram study, thermal study of the pure compounds and the eutectics such as heat of fusion, Jackson’s roughness parameter, excess thermodynamic functions, and microstructural study. However
, calculation of standard ( p ° = 0.1 MPa) thermodynamic functions: , H °( T ) − H °(0), S °( T ), and G °( T ) − H °(0) of crystalline Ph 4 SbONCPhMe from T → 0 K to 350 K using the experimental data, determination of combustion energy of the compound
are important basic thermodynamic function of substances. Based on the polynomials of molar heat capacity and the thermodynamic relationships, the [ H T − H 298.15 ] and [ S T − S 298.15 ] of DPFEB are calculated over the experimental temperature
–380 K. The thermodynamic properties including molar enthalpy and entropy of phase transition were determined based on the heat capacity measurement. Further more, the thermodynamic functions such as [ ] and [ ] were calculated from the heat capacity
– 22 ] as examples). The aim of this study was to study the heat capacity of this crystal in a wide temperature range by adiabatic calorimetry, to calculate the thermodynamic functions and to compare the results with those previously obtained
]. In this study results of experimental studying of temperature dependence of a heat capacity of crystal compound Ba 0.5 Zr 2 (PO 4 ) 3 over the temperature range 6–612 K are presented, the standard thermodynamic functions C p o ( T ), H °( T ) − H
Abstract
The heat capacity of solid NdBr3 was measured by Differential Scanning Calorimetry in the temperature range from 300 K up to the melting temperature. The heat capacity of liquid NdBr3 was also determined. These results were least-squares fitted to a temperature polynome. The melting enthalpy of NdBr3 was measured separately. DSC was used also to study phase equilibrium in the NdBr3-LiBr system. The results obtained provided a basis for constructing the phase diagram of the system under investigation. It represents a typical example of simple eutectic system. The eutectic composition, x(NdBr3)=0.278, was obtained from the Tamman construction. This eutectic mixture melts at 678 K. The electrical conductivity of NdBr3-LiBr liquid mixtures and of pure components was measured down to temperatures below solidification. Reflectance spectra of the pure components and their solid mixtures (after homogenisation in the liquid state) with different composition were recorded in order to confirm the reliability of the constructed phase diagram.
Summary As part of a larger study of the physical properties of potential ceramic hosts for nuclear wastes, we report the molar heat capacity of brannerite (UTi2O6) and its cerium analog (CeTi2O6) from 10 to 400 K using an adiabatic calorimeter. At 298.15 K the standard molar heat capacities are (179.46±0.18) J K-1 mol-1 for UTi2O6 and (172.78±0.17) J K-1 mol-1 for CeTi2O6. Entropies were calculated from smooth fits of the experimental data and were found to be (175.56±0.35) J K-1 mol-1 and (171.63±0.34) J K-1 mol-1 for UTi2O6 and CeTi2O6, respectively. Using these entropies and enthalpy of formation data reported in the literature, Gibb’s free energies of formation from the elements and constituent oxides were calculated. Standard free energies of formation from the elements are (-2814.7±5.6) kJ mol-1 for UTi2O6 and (-2786.3±5.6) kJ mol-1 for CeTi2O6. The free energy of formation from the oxides at T=298.15 K are (-5.31±0.01) kJ mol-1 and (15.88±0.03) kJ mol-1 for UTi2O6 and CeTi2O6, respectively.
