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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, the removal of nickel (Ni(II)) by adsorption from synthetically prepared solutions using natural bentonites (Lieskovec (L), Hlinik nad Hronom (S), Jelsový Potok (JP), and Stara Kremnicka (SK)) was investigated.
Abstract: In this study, the removal of nickel (Ni(II)) by adsorption from synthetically prepared solutions using natural bentonites (Lieskovec (L), Hlinik nad Hronom (S), Jelsový Potok (JP), and Stara Kremnicka (SK)) was investigated. All experiments were carried out under batch processing conditions, with the concentration of Ni(II), temperature, and time as the variables. The adsorption process was fast, approaching equilibrium within 30 min. The Langmuir maximum adsorption capacities of the four bentonite samples used were found to be 8.41, 12.24, 21.79, and 21.93 mg g-1, respectively. The results best fitted the pseudo-second-order kinetic model, with constant rates in a range of 0.0948-0.3153 g mg-1 min. The effect of temperature was investigated at temperatures of 20, 30, and 40 °C. Thermodynamic parameters, including standard enthalpy (ΔH0), Gibbs energy (ΔG0), and standard entropy (ΔS0), were calculated. The adsorption of Ni(II) by bentonite samples was an endothermic and spontaneous process. These results indicated that, of the bentonite samples used, the natural bentonites from JP and SK were most suitable for the removal of nickel from synthetically prepared solutions.
8 citations
TL;DR: In this article, the ternary compound Tl5Te2Cl characterized by a wide homogeneity region and incongruent melting by a syntectic reaction at 708 K was shown to crystallize in a tetragonal lattice.
Abstract: The Tl-Te-Cl system was studied in the Tl-TlCl-Te composition region by differential thermal analysis, X-ray powder diffraction, and emf and microhardness measurements. A series of polythermal sections, an isothermal section at 400 K, and a projection of the liquidus surface of the phase diagram were constructed. The ternary compound Tl5Te2Cl characterized by a wide homogeneity region and incongruent melting by a syntectic reaction at 708 K was shown to exist. This compound was found to crystallize in tetragonal lattice (space group I4/mcm) with the parameters a = 8.921 A, c = 12.692 A, Z = 4. Wide phase separation regions were also found in the system, including a three-phase separation region in the Tl-TlCl-Tl2Te subsystem. Regions of primary crystallization of phases, and the types and coordinates of in- and monovariant equilibria in the T-x-y diagram were determined. From emf measurement data, the standard thermodynamic functions of formation and the standard entropy were calculated for the compound Tl5Te2Cl, as follows: −ΔG2980 = 355.9 ± 1.1 kJ/mol, −ΔH2980 = 377.1 ± 5.0 kJ/mol, and S2980 = 474.1 ± 6.8 J/(mol K).
8 citations
TL;DR: In this article, the temperature dependence of the heat capacity of crystalline barium zirconium phosphate was measured over the temperature range 6-612-K. The experimental data obtained were used to calculate the standard thermodynamic functions CSpaceEngineers p�� o¯¯¯¯ (T), H°(T)−H°(0), S°(t), G°T) −H°T, S°T, G°G°T), T −H −H−T −T −G°H −T−T−G°F(T), G
Abstract: The temperature dependence of the heat capacity of crystalline barium zirconium phosphate C
p
o
= f(T) was measured over the temperature range 6–612 K. The experimental data obtained were used to calculate the standard thermodynamic functions C
p
o
(T), H°(T) − H°(0), S°(T), G°(T) − H°(0) over the temperature range from T → 0 to 610 K and standard entropy of formation at 298.15 K. The data on the low-temperature (6 ≤ T/K ≤ 50) heat capacity were used to determine the fractal dimension of Ba0.5Zr2(PO4)3. Conclusions concerning the topology of the structure of phosphate were drawn. Thermodynamic properties of M0.5Zr2(PO4)3 (M = Ca, Sr, Ba) were compared.
8 citations
TL;DR: In this article, the standard molar entropy of formation of Rb2B4O7·5.6H2O was calculated from the thermodynamic relation of the standard enthalpy of formation with the standard Molar Gibbs free energy of formation.
8 citations
TL;DR: In this paper, the surface pressure of mixed monolayers of butyl eicosanedioate and tetradecanoic acid was measured as a function of mean area at various compositions and temperatures.
Abstract: In order to clarify the behavior of mixed monolayers of butyl eicosanedioate and tetradecanoic acid, the surface pressure was measured as a function of mean area at various compositions and temperatures. Four types of phase transition were observed. By use of the thermodynamic treatment previously developed, the apparent molar entropy and energy changes associated with the phase transition were evaluated. It was concluded on thermodynamic considerations that the butyl eicosanedioate and tetradecanoic acid monolayers are immiscible in condensed states and their phase diagram has a two-dimensional eutectic point.
8 citations