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.

Relation between standard entropies of elements and electronic configurations

Abstract: A close relationship has been found between the standard entropies of elements and their electronic configurations. Based on the positions of elements in the periodic table and the variation in the standard entropies of elements, the standard entropies of elements can be expressed as the sum of two functions:S0=f(N) +f(E), whereS0 is the standard entropy of an element,N the principal quantum number, andE the number of outermost electrons. And the specific formula isS0 = 99.05N1/3 + [0.32(sp −4)4 -119.76] + [-56.56N1/3+ 0.70(sd ∼-7)2 −42.12] + [−11.95 × 10−4(df-8)−4 -105.70], wheresp, sd, df are the numbers of the outermost electrons in thesp, sd, df regions of the periodic table, respectively. This formula helps reveal the essence of the standard entropies of elements and deepens our understanding of the thermodynamic characteristics of compounds.

Estimation model for standard entropy of intermetallics

Abstract: A two-parameter model for estimating the standard entropy of binary intermetallics was developed based on the analysis of existing thermodynamic dataThe model can estimate the standard entropy of binary intermetallics formed by simple metals,involving the multi-systems of Fe,Si,Nb,Ti,Cu,Co,Mg,etcThe standard entropies of 132 intermetallics,such as AlCa,AlCo,CrNi,FeTi,FeSi,FeNb and MoSi,were estimatedIt is found that the average error of standard entropy is about 486 J·mol-1·K-1 and the standard deviation is 624 J·mol-1·K-1The accuracy of standard entropy estimated by the two-parameter model is higher than that estimated by the ion binding model

Electrochemical Approach in Plasma Display Panel Glass Melts doped with Sulfate and Sulfide II. Square Wave Voltammetry

Abstract: Redox behavior was observed in alkali alkaline earth silicate PDP (Plasma Display Panel) glass melts doped with sulfate and sulfide by square wave voltammetry (SWV). According to voltammograms produced at a temperature range of 1100 to 1400℃ and frequency range of 5 to 1000 ㎐, both melts showed the same behavior in which there is one reduction peak at low frequency but another peak at an increase of frequency. Based on the frequency dependence of the peak current, self diffusivity of S 4+ was determined. Based on the temperature dependence of the peak potential, standard enthalpy (ΔH?) and standard entropy (ΔS0) for the reduction of S 4+ to S? were calculated.

Phase equilibria in the PbSe-Bi2Se3-Se system and thermodynamic properties of intermediate phases

Abstract: The Pb-Bi-Se system in the PbSe-Bi2Se3-Se-Se composition region was studied by measurement of concentration circuits of the type (−) PbSe(solid) liquid electrolyte, Pb2+(Pb-Bi-Se)(solid) (+) in the temperature range 300–430 K and by X-ray powder diffraction. A solid-phase equilibrium diagram was constructed, and the formation was confirmed for the ternary compounds Pb5Bi6Se14, Pb5Bi12Se23, and Pb5Bi18Se32, which belong to the homologous series [(PbSe)5]m · [(Bi2Se3)3]n. From the emf versus temperature equations, the partial thermodynamic functions \(\overline {\Delta G}\), \(\overline {\Delta H}\), \(\overline {\Delta S}\) of PbSe in alloys were calculated. Based on the solid-phase equilibrium diagram from these partial molar quantities using the corresponding data for PbSe and Bi2Se3, the standard thermodynamic functions of formation and standard entropies of the above ternary compounds were calculated.