temperature dependence of the molar heat capacities of the tellurites CoTeO3,
MnTeO3 and MnTe6O13
are determined. By statistical manipulation of the values obtained, the parameters
in the equations for the corresponding compounds showing this dependence are
determined using the least-squares method. These equations and the standard
molar entropies are used to determine the thermodynamic functions for T'=298.15 K.
Authors:B. Liu, X. Lv, Z. Tan, Z. Zhang, Q. Shi, L. Yang, J. Xing, L. Sun, and T. Zhang
The molar heat capacity, Cp,m, of a complex of holmium chloride coordinated with L-aspartic acid, Ho(Asp)Cl2·6H2O, was measured from 80 to 397 K with an automated adiabatic calorimeter. The thermodynamic functions HT-H298.15 and ST-S298.15 were derived from 80 to 395 K with temperature interval of 5 K. The thermal stability of the complex was investigated by
differential scanning calorimeter (DSC) and thermogravimetric (TG) technique, and the mechanism of thermal decomposing of
the complex was determined based on the structure and the thermal analysis experiment.
Authors:M. Fujisawa, T. Matsushita, M. A. Khan, and T. Kimura
Excess molar heat capacities of (L-glutamine aqueous solution+D-glutamine aqueous solution) were determined by using a differential scanning calorimeter at temperatures between 293.15 and 303.15 K. Excess molar heat capacities are all negative. Excess molar heat capacities decrease with increasing temperature.
The molar heat capacity Cp,m of 1,2-cyclohexane dicarboxylic anhydride was measured in the temperature range from T=80 to 390 K with a small sample automated adiabatic calorimeter. The melting point Tm, the molar enthalpy ΔfusHm and the entropy ΔfusSm of fusion for the compound were determined to be 303.80 K, 14.71 kJ mol−1 and 48.43 J K−1 mol−1, respectively. The thermodynamic functions [HT-H273.15] and [ST-S273.15] were derived in the temperature range from T=80 to 385 K with temperature interval of 5 K. The thermal stability of the compound was investigated by differential scanning
calorimeter (DSC) and thermogravimetry (TG), when the process of the mass-loss was due to the evaporation, instead of its
properties [ 7 , 8 ] such as molarheatcapacities C p,m of compound at different temperatures, from which many other thermodynamic properties can be calculated for both theoretical and practical purposes.
In the present study, a complex of Erbium
Experimental data of excess molar enthalpy (HmE) and excess molar heat capacity (CpmE) of binary mixtures containing (1-heptanol or 1-octanol)+(diethylamine or s-butylamine) have been determined as a function of composition at 298.15 K and at 0.1 MPa using a modified 1455 Parr solution
calorimeter. The excess molar enthalpy data are negative and show parabolic format over the whole composition range; however,
the excess molar heat capacity values, whose curves show a S-shape, are positive in the 0.0 to 0.7 molar fraction range and
negative between the molar fraction values 0.7 to 1.0. The applicability of the ERAS-model to correlate the excess molar enthalpy
data was tested. The calculated data values are in good agreement with the experimental ones. The experimental behavior of
HmE is interpreted in terms of specific interactions between 1-alkanol and amine molecules.
Authors:J. Zhang, Z. Tan, Q. Meng, Q. Shi, B. Tong, and S. Wang
The heat capacities (Cp,m) of 2-amino-5-methylpyridine (AMP) were measured by a precision automated adiabatic calorimeter over the temperature range
from 80 to 398 K. A solid-liquid phase transition was found in the range from 336 to 351 K with the peak heat capacity at
350.426 K. The melting temperature (Tm), the molar enthalpy (ΔfusHm0), and the molar entropy (ΔfusSm0) of fusion were determined to be 350.431±0.018 K, 18.108 kJ mol−1 and 51.676 J K−1 mol−1, respectively. The mole fraction purity of the sample used was determined to be 0.99734 through the Van’t Hoff equation.
The thermodynamic functions (HT-H298.15 and ST-S298.15) were calculated. The molar energy of combustion and the standard molar enthalpy of combustion were determined, ΔUc(C6H8N2,cr)= −3500.15±1.51 kJ mol−1 and ΔcHm0 (C6H8N2,cr)= −3502.64±1.51 kJ mol−1, by means of a precision oxygen-bomb combustion calorimeter at T=298.15 K. The standard molar enthalpy of formation of the crystalline compound was derived, ΔrHm0 (C6H8N2,cr)= −1.74±0.57 kJ mol−1.
The temperature dependencies of the molar heat capacities of ZnTeO3, Zn2Te3O8, CdTeO3 and CdTe2O5 are determined. The experimental data are statistically processed using the least squares method to determine the parameters in the equations for the corresponding compounds: Cp,m=a+b(T/K)-c(T/K)-2. These equations and the standard molar entropies are used to determine ΔT0S0m, ΔTTH0m and (Φ0m+ΔT,0H0m/T) for T'=298.15 K.
The temperature dependence of the molar heat capacities of the tellurites Fe2(TeO3)3, Fe2TeO5 and Fe2Te4O11 were determined. By statistical manipulation of the values obtained, the parameters in the equations for the corresponding
compounds showing this dependence were determined using the least-squares method. These equations together with the standard
molar entropies were used to determine the thermodynamic functions Δ0TSm0, ΔTT,Hm0 and (Φm0 + Δ0T’Hm0 / T) for T’=298.15 K.