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Standard molar entropy
About: Standard molar entropy is a research topic. Over the lifetime, 1586 publications have been published within this topic receiving 29886 citations.
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TL;DR: In this article, new protic ionic liquids (PILs) based on 1-methylimidazolium/1-propanenitrileimidazilium cations with hydrogen sulfate, methanesulfonate, trifluoromethane sulfonates, para-toluenesulfonates and triflooracetate anions were synthesized.
Abstract: In this work, new protic ionic liquids (PILs) based on 1-methylimidazolium/1-propanenitrileimidazolium cations with hydrogen sulfate, methanesulfonate, trifluoromethanesulfonate, para-toluenesulfonate, trifluoroacetate, and acetate anions were synthesized. The structures and purity of the products were confirmed by using 1H and 13C NMR and CHNS elemental analysis. The effect of structural variations on the thermophysical properties, namely, refractive index, density, and viscosity, was evaluated in a wide temperature range. The viscosity and density values were measured within the temperature range of 293.15–373.15 K. The density values were used further to calculate more properties like thermal expansion coefficient, molecular volume, standard entropy, and the lattice energy. Moreover, the experimental values of viscosity were used for the calculation of activation energy. Refractive indices were measured within the temperature range of 293.15–323.15 K, and these values were also used in the calculation ...
19 citations
TL;DR: In this article, the standard molar entropy of the formation of ulexite was calculated from the thermodynamic relation with the standard Molar Gibbs free energy of formation of Ulexite computed from its solubility in water.
19 citations
TL;DR: The present work reports an energetic and structural study of 2-fluoro-, 3-fluoros-, and 4-fluorobenzonitrile, where the geometries were reoptimized at MP2/cc-pVTZ level, and the QTAIM and NICS were computed.
Abstract: The present work reports an energetic and structural study of 2-fluoro-, 3-fluoro-, and 4-fluorobenzonitrile. The standard molar enthalpies of formation, in the condensed phase, of the three isomers were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K. The standard molar enthalpies of vaporization or sublimation (for 4-fluorobenzonitrile), at T = 298.15 K, were measured using high-temperature Calvet microcalorimetry. The combination of these two parameters yields the standard molar enthalpies of formation in the gaseous phase. The vapor-pressure study of the referred compounds was performed by a static method, and the enthalpies of phase transition derived from the application of the Clarke and Glew equation. Theoretically estimated gas-phase enthalpies of formation, basicities, proton and electron affinities, and adiabatic ionization enthalpies were calculated from the G3MP2B3 level of theory. In order to evaluate the electronic properties, the geometries were reoptimiz...
19 citations
TL;DR: In this article, the standard free energies of formation of zinc chalcogenides (ZnTe, ZnSe and α-ZnS) have been determined by an electrochemical technique using LiCl-KCl + 5 wt.% ZnCl 2 electrolyte.
18 citations
TL;DR: In this paper, the heat capacities of 1,4-dichlorobenzene, 1, 4-dibromobenzenes, and 1, 3, 5-trichlorobenenzene were measured by adiabatic calorimetry.
Abstract: The heat capacities of 1,4-dichlorobenzene, 1,4-dibromobenzene, and 1,3,5-trichlorobenzene from 5 K to 380 K and 1,3,5-tribromobenzene from 5 K to 410 K were measured by adiabatic calorimetry. The experimental data were used to calculate the molar entropy and enthalpy values relative to 0 K. Apart from 1,4-dichlorobenzene, the substances do not show any solid−solid transitions. Molar enthalpies of fusion and melting-point temperatures were determined. The results, given in order, are (17 907 ± 15) J·mol-1 and (326.24 ± 0.03) K, (20 387 ± 15) J·mol-1 and (360.48 ± 0.03) K, (17 557 ± 35) J·mol-1 and (335.92 ± 0.03) K, and (21 721 ± 20) J·mol-1 and (394.96 ± 0.07) K.
18 citations