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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 paper, the performance of complex formation in acetonitrile (AN)-N,N-dimethylformamide (DMF) binary solutions at different temperatures using conductometric method was investigated.
Abstract: The complexation of Y3+, La3+, and nd Hg2+ cations with macrocyclic ligands, dicyclohexyl-18-crown-6 (DCH18C6) and 15-crown-5 (15C5) have been studied in acetonitrile (AN)-N,N-dimethylformamide (DMF) binary solutions at different temperatures using conductometric method. The conductance data revealed 1: 1 [ML] stoichiometry for most complexes in pure DMF and AN-DMF binary solutions, except for the (DCH18C6-Y3+) complex in pure AN (1: 2, [ML2]). The stability constants of DCH18C6-La3+ and 15C5-La3+ in pure AN were higher than in pure DMF at all temperatures. Nonlinear behavior was observed for the stability constants of complexes against the composition of AN-DMF binary solutions at all temperatures. The minimum log K
f value for the 15C5-La3+ complex in AN-DMF binary solutions was obtained at χAN = 0.5, which may be due to negative excess viscosities ηE of AN-DMF mixtures over the whole composition range with a minimum value of χAN = 0.5. Moreover, the selectivity order of DCH18C6 and 15C5 for Y3+, La3+, and Hg2+ cations 25°C depended on the AN-DMF ratio. The thermodynamic parameters (ΔH
C
0
) for complex formation were obtained from the temperature dependences of the stability constants of the complexes using the van’t Hoff plots, and the standard entropy (ΔS
C
0
) was calculated from the relationship: ΔG
C, 298.15
0
= ΔH
C
0
− 298.15ΔS
C
0
.
1 citations
TL;DR: In this paper, the enthalpies of solution of K2Sr[B4O5(OH)4]2·10H2O(cr) were measured by solution calorimetry.
1 citations
TL;DR: In this paper, the temperature dependence of the heat capacity of triphenylbismuth dibenzoate Ph3Bi(OC(O)Ph)2 was measured for the first time in the range of Т = (6 and 480) K using precision adiabatic vacuum and differential scanning calorimeters.
Abstract: The temperature dependence of the heat capacity of triphenylbismuth dibenzoate Ph3Bi(OC(O)Ph)2 is measured for the first time in the range of Т = (6 and 480) K using precision adiabatic vacuum and differential scanning calorimeters. It is found that the melts with decomposition in the considered range of temperatures, and its standard thermodynamic characteristics are analyzed. Standard thermodynamic functions of Ph3Bi(OC(O)Ph)2 in the crystalline state from Т → 0 to 417 K are calculated using the obtained experimental data. The chain-planar topological structure of the compound is established by subjecting the low-temperature heat capacity to multifractal treatment. The data are used to determine w the compound’s standard entropy of formation ∆fS° in the crystal state at T = 298.15 K. The thermodynamic properties of triphenylbismuth dibenzoate and triphenylantimony dibenzoate are compared, as are the compounds’ thermodynamic characteristics of fusion.
1 citations
TL;DR: The theoretical van der Waals interaction of parallel gold nanowires in matrix form with free extremities using molecular mechanics is studied and new information is found about the nanowire behavior due to the matrix form.
Abstract: We study the theoretical van der Waals interaction of parallel gold nanowires (GNs) in matrix form with free extremities using molecular mechanics. It was calculated force, velocity, efficiency, thermodynamics properties like molar heat capacity, molar entropy variation and the relation between kinetic energy and temperature in situ of the GNs. We found new information about the nanowire behavior due to the matrix form. Each nanowire has 20 atoms and distant 27.78 angstroms from each one.
1 citations
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TL;DR: The authors carried out a systematic comparison of the label-shape entropy and degree entropy measures for trees, and found that the label shape entropy measure is more accurate than the degree entropy measure for trees.
Abstract: Whereas for strings, higher-order empirical entropy is the standard entropy measure, several different notions of empirical entropy for trees have been proposed in the past, notably label entropy, degree entropy, conditional versions of the latter two, and empirical entropy of trees (here, called label-shape entropy). In this paper, we carry out a systematic comparison of these entropy measures. We underpin our theoretical investigations by experimental results with real XML data.
1 citations