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Abstract  

From measurements of the enthalpy of solution of metal salts of 3-nitro-1,2,4-triazol-5-one (NTO) in water, the standard enthalpies of formation of KNTO·H2O, Ba(NTO)2·3H2O, LiNTO·2H2O, Ca(NTO)2·4H2O and Gd(NTO)3·7H2O were determined as −(676.9±2.6), −(1627.0±2.5), −(966.6.3±2.2), −(1905.5±4.4) and −(3020.1±6.4) kJ·mol−1, respectively. From measurements of the enthalpy of precipitation of KNTO·H2O crystal with Pb(NO3)2(aq), CuSO4(aq) and Zn(NO3)2(aq), the standard enthalpies of formation of Pb(NTO)2·H2O, Cu(NTO)2·2H2O and Zn(NTO)2·H2O were determined as −(247.4±5.9), −(712.1±5.4) and −(628.8±5.7) kJ·mol−1, respectively.

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Abstract  

[Cd(NTO)4Cd(H2O)6]4H2O was prepared by mixing the aqueous solution of 3-nitro-1,2,4-triazol-5-one and cadmium carbonate in excess. The single crystal structure was determined by a four-circle X-ray diffractometer. The crystal is monoclinic, space group C2/c with crystal parameters of a=2.1229(3) nm, b=0.6261(8) nm, c=2.1165(3) nm, β=90.602(7), V=2.977(6) nm3, Z=4, Dc=2.055 gcm−3, μ=15.45 cm−1, F(000)=1824, λ(MoKα)=0.071073 nm. The final R is 0.0282. Based on the results of thermal analysis, the thermal decomposition mechanism of [Cd(NTO)4Cd(H2O)6]4H2O was derived. From measurements of the enthalpy of solution of [Cd(NTO)4Cd(H2O)6]4H2O in water at 298.15 K, the standard enthalpy of formation, lattice energy, lattice enthalpy and standard enthalpy of dehydration have been determined as -(1747.84.8), -2394, -2414 and 313.6 kJ mol−1 respectively.

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Instrumentation and calibration of the Calvet calorimeter

Enthalpy of solution of PrBr3 at standard conditions

Journal of Thermal Analysis and Calorimetry
Authors: Beata Salamon, Jan Kapała, and Marcelle Gaune-Escard

values is insignificant. However, for the calculation of the enthalpy of solution the values of calorimeter constant were used separately. The quality of heating the reference material was controlled by analysis of the temperature dependence of

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Introduction Thermal properties of tetraalkylammonium (TAA) salt solutions in non-aqueous binary solvents containing formamide were studied in set of the works [ 1 – 4 ]. In the article [ 1 ], the enthalpies of solution of

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spectrometer operating at 400 Hz. Microcalorimetric study Isoperibol solution calorimetry (ISC) model 4300 (Calorimetry Science Corporation, UTAH, USA) was used to determine the enthalpy of solution. It is a semi

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the energetic effects of interactions between selected zwitterions of amino acids and dissociated KCl, the enthalpies of solutions of the amino acids under discussion in aqueous solutions of potassium chloride were measured by the calorimetric method

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series, namely: glycine, l -alanine, and l -proline. However, the solubility of proline in water is much higher than even glycine and its enthalpy of solution in water is exothermic unlike other amino acids. It was shown that in terms of heat capacity

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Abstract  

The tetra-alkyl-ammonium halides are electrolytes that have special characteristics due to the presence of hydrocarbon chains. They have been used asmodel compounds to study hydrophobic interactions due to their fairly large solubility in water and because of the possibility of change in the length and geometry of the alkyl chains. In this work the solution enthalpies of tetra-n-butyl-ammonium bromide, tetra-sec-butyl ammonium bromide, tetra-iso-butyl-ammonium bromide and di-n-butyl-di-sec-butyl ammonium bromide were determined at 298.15 K at concentrations between 0.001 and 0.01 mol kg−1. The experimental method used was isoperibol calorimetry. The results were extrapolated fitting the experimental data by least squares to obtain the solution enthalpies at infinite dilution. The hydrocarbon chains studied were so chosen because the tetra-n-butyl-ammonium ion is considered to be a structure maker for water. The results show that the geometry of the ion and of the hydrocarbon chains play an important role in the behavior properties of the solutions.

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—the number of carbon atoms of TAA ion. In this article, we report the integral enthalpies of solution of tetra- n -hexylammonium bromide in anhydrous MeOH, FA, and EG at 298.15 and 313.15 K. The experimental Δ sol H m values have been

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Journal of Thermal Analysis and Calorimetry
Authors: V. I. Pet’kov, E. A. Asabina, A. V. Markin, N. N. Smirnova, and D. B. Kitaev

Summary The thermodynamic data for NZP compounds MZr2(PO4)3 (M=Na, K, Rb, Cs, Zr0.25) and Na5D(PO4)3 (D=Ti, Zr) are reported. The heat capacities of the phosphates were measured between T=7 and T=640 K. The standard enthalpies entropies, and Gibbs functions of formation at T=298.15 K were derived. The obtained thermodynamic characteristics of phosphates of the NZP type structure and literature data are summarized. Thermodynamic functions of reactions of solid-state synthesis were calculated and the usability of ceramic technology for obtaining NZP compounds was proved.

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