Topic
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: The computational results diagnose the most stable conformer of 2A5BrBA as the C1 form, while the observed and the calculated geometric parameters, vibrational wavenumbers and electronic transitions were compared with observed data and found to be in good agreement.
85 citations
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TL;DR: In this article, an equilibrium and thermodynamic study of the removal of cadmium by adsorption on an indigenous adsorbent, china clay, have been investigated.
84 citations
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TL;DR: In this article, an explicit representation of molar entropy for gaseous substances is presented, and the molar entropies can be successfully predicted by applying experimental values of only four molecular constants for the carbon monoxide, hydrogen chloride, hydrogen fluoride, deuterium fluoride and nitrogen monoxide.
83 citations
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TL;DR: A complete and consistent set of 95 Benson group additive values (GAVs) for standard entropies S(o) and heat capacities C(p)(o) of hydrocarbons and hydrocarbon radicals is presented, including 46 groups, among which 25 radical groups, which have not been reported before.
Abstract: In this work a complete and consistent set of 95 Benson group additive values (GAVs) for standard entropies S(o) and heat capacities C(p)(o) of hydrocarbons and hydrocarbon radicals is presented These GAVs include 46 groups, among which 25 radical groups, which, to the best of our knowledge, have not been reported before The GAVs have been determined from a set of B3LYP/6-311G(d,p) ideal gas statistical thermodynamics values for 265 species, consistently with previously reported GAVs for standard enthalpies of formation One-dimensional hindered rotor corrections for all internal rotations are included The computational methodology has been compared to experimental entropies (298 K) for 39 species, with a mean absolute deviation (MAD) between experiment and calculation of 12 J mol(-1) K(-1), and to 46 experimental heat capacities (298 K) with a resulting MAD = 18 J mol(-1) K(-1) The constructed database allowed evaluation of corrections on S(o) and C(p)(o) for non-nearest-neighbor effects, which have not been determined previously The group additive model predicts the S(o) and C(p)(o) within approximately 5 J mol(-1) K(-1) of the ab initio values for 11 of the 14 molecules of the test set, corresponding to an acceptable maximal deviation of a factor of 16 on the equilibrium coefficient The obtained GAVs can be applied for the prediction of S(o) and C(p)(o) for a wide range of hydrocarbons and hydrocarbon radicals The constructed database also allowed determination of a large set of hydrogen bond increments, which can be useful for the prediction of radical thermochemistry
82 citations
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TL;DR: In this article, a simple method for providing natural hydroxyapatite/chitosan composite is introduced and adsorption suitability of this composite for treating the solutions containing Cu(II) ions has been studied.
Abstract: In this study, a simple method for providing natural hydroxyapatite/chitosan (N-HAP/chitosan) composite is introduced and adsorption suitability of this composite for treating the solutions containing Cu(II) ions has been studied. Kinetic and isotherm studies were carried out by studying the effects of parameters such as adsorbent particle size, temperature and pH. The equilibrium data at different temperatures were analyzed by Langmuir and Freundlich isotherms. Equilibrium data agreed well with Langmuir isotherm, based on this model the maximum adsorption capacity of N-HAP/chitosan composite for Cu(II) was found to be 1.776 mmol/g at pH 7.50 and 25 °C for 47.6 nm adsorbent particle size. A pseudo-second order kinetic model has been proposed to correlate the experimental data. The thermodynamic parameters such as standard Gibb's free energy (ΔG°), standard enthalpy (ΔH°), standard entropy (ΔS°) and activation energy (Ea) were evaluated by applying the Van’t Hoff and Arrhenius equations. The results reveal Cu(II) adsorption onto N-HAP/chitosan is spontaneous, has endothermic nature and is followed by physisorption.
82 citations