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Showing papers on "Standard molar entropy published in 2022"


Journal ArticleDOI
TL;DR: In this paper , a formulation representation of the molar Gibbs free energy for sulfur dioxide (SO2) was proposed, which depends only on experimental values of six molecular constants of SO2, whereas the conventional explicit representations contain many adjustable coefficients determined from fitting a great number of experimental spectroscopic data or calorimetric data.

24 citations


Journal ArticleDOI
TL;DR: In this article , the characterization of the crystal structure of niobium oxide and a metal-organic framework is investigated, and the information function is used to compute entropies by building these structures with degree-based indices.
Abstract: Entropy is a thermodynamic function in chemistry that reflects the randomness and disorder of molecules in a particular system or process based on the number of alternative configurations accessible to them. Distance-based entropy is used to solve a variety of difficulties in biology, chemical graph theory, organic and inorganic chemistry, and other fields. In this article, the characterization of the crystal structure of niobium oxide and a metal–organic framework is investigated. We also use the information function to compute entropies by building these structures with degree-based indices including the K-Banhatti indices, the first redefined Zagreb index, the second redefined Zagreb index, the third redefined Zagreb index, and the atom-bond sum connectivity index.

11 citations


Journal ArticleDOI
TL;DR: In this article , Almond shells (AS) were used as an adsorbent to remove methyl orange (MO) from aqueous solutions, which reached equilibrium at 90 min following the pseudo-second-order (PSO) kinetic model.
Abstract: In recent years, the removal of dyes has emerged as a significant problem that attracted several researchers. The search for green and eco-friendly adsorbents has been a never-ending task in environmental protection to overcome this issue. Herein, almond shells (AS) were used as an adsorbent to remove methyl orange (MO) from aqueous solutions. The AS was characterized using several techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). Adsorption experiments were carried out under different pH, temperature, and AS particle size conditions. Kinetic and isothermal studies revealed that MO adsorption on the AS reached equilibrium at 90 min, following the pseudo-second-order (PSO) kinetic model. The Langmuir adsorption isotherm was found the suitable adsorption model for MO adsorption on AS, showing a maximum adsorption capacity of 15.63 mg/g. Thermodynamic parameters such as the change in standard enthalpy (ΔH°), the change in standard entropy (ΔS°), and the change in standard free energy (ΔG°) indicated that the MO dye adsorption process is non-spontaneous, endothermic, and physical, which was further confirmed from FTIR analysis of AS samples after adsorption. The contaminated sludge was converted into biochar by slow pyrolysis at a temperature of 400 °C for 2 h. Biochar has been exploited for the manufacture of combustible briquettes.

9 citations


Journal ArticleDOI
TL;DR: In this article , the effect of adenosine and temperature on the micellization of cationic gemini surfactant, hexanediyl-1,6-bis(dimethylcetylammonium bromide (16-6-16) solutions was measured by conductivity, surface tension measurements, fluorometric and dye solubilisation methods.

5 citations


Journal ArticleDOI
TL;DR: In this article , the development of a heterogeneous magnetic nanocatalyst composed of SrO/MgFe2O4 (Sr/MGF) for efficient methanolysis of waste cooking oil (WCO) is addressed.

5 citations


Journal ArticleDOI
TL;DR: In this article, the authors improved the solubility of flunarizine hydrochloride by co-solvent in two binary mixtures and showed that the enthalpy is the main contributor to the standard free energy of solution process.

4 citations


Journal ArticleDOI
TL;DR: In this paper , the authors show that strong synergistic interactions exist between trimethyl(tetradecyl)ammonium bromide (TB) and sodium deoxycholate surfactants (SD) particles, and that the molar excess entropy is zero.

4 citations


Journal ArticleDOI
TL;DR: In this paper , the solubility of CO 2 in three protic ionic liquids was measured and experimental data were correlated with Pitzer's model and Soave-Redlich-Kwong cubic equation of state.

3 citations


Journal ArticleDOI
TL;DR: In this article , N -Butylethanolammonium trifluoroacetate [BEATFA] and N -butylethanolate ammonium nitrate [BEAN] ionic liquids (ILs) were synthesized and characterized by 1 H NMR.

3 citations


Journal ArticleDOI
TL;DR: In this article , structural and thermophysical properties of Nd3+ substituted Y3Al5O12 (YAG) were investigated for burning minor actinides (MA) for reducing the long-term radiotoxicity of nuclear wastes.

3 citations


Journal ArticleDOI
TL;DR: In this paper , the thermal properties of aqueous electric double layer capacitors with KOH electrolytes were measured using the in situ and operando 3ω hot-wire method.

Journal ArticleDOI
TL;DR: In this paper , two forms of zeolite-A: the hydrated phase and the dehydrated phase (DH.ZA) were synthesized by conventional hydrothermal and alkali fusion methods.
Abstract: Egyptian kaolinite was applied in the synthesis of zeolite-A by conventional hydrothermal and alkali fusion methods, resulting in two forms of zeolite-A: the hydrated phase (H.ZA) and the dehydrated phase (DH.ZA). The DH.ZA phase exhibits an enhanced surface area (488 m2/g), total basicity (7.73 mmol OH/g), high sodium content (20.2%), and a narrow particle size distribution (5 to 25 µm) as compared to the H.ZA phase (423 m2/g surface area, 5.88 mmol OH/g total basicity, 13.3% sodium content, and 10 to 45 µm particle size distribution). DH.ZA exhibits enhanced catalytic activity, achieving a biodiesel yield of 96.8% after 60 min at 60 °C, while the application of H.ZA resulted in a 95.8% yield after 120 min at 80 °C. The controlled transesterification mechanism in the presence of H.ZA and DH.ZA involved robust base-catalyzed reactions. The reactions follow the pseudo-first-order kinetics, and the rate constants (Kc) were determined at three different temperature values (40, 50 and 60 °C). The activation energies using H.ZA (35.9 kJ.mol−1) and DH.ZA (32.714 kJ.mol−1) demonstrates their efficiencies in mild conditions. The thermodynamic parameters of enthalpy (33.23 kJ.mol−1 (H.ZA) and 30.03 kJ.mol−1 (DH.ZA)), Gibb’s free energy (65.164 kJ.mol−1 (H.ZA) and 65.268 kJ.mol−1 (DH.ZA)), and entropy (−195.59 J.K−1.mol−1 (H.ZA) and −195.91 J.K−1.mol−1 (DH.ZA)) demonstrate the spontaneous and endothermic behaviours of these reactions. The obtained biodiesel matches the physical properties of the international standards, and the recyclability properties of the two zeolite phases demonstrate their suitability for commercial-scale applications.


Journal ArticleDOI
TL;DR: In this paper , the authors investigated the thermodynamic data of sodium ion half/full cells based on Na 3 V 2 (PO 4 ) 3 and hard carbon material, and showed that the trend of Δ S for Na ∣∣ Na 3V 2(PO 4 ), 3 exhibits great change at 0%−10% and 90%−100% SOCs (states of charge), and remains constant (≈−14.54 J·mol −1 ·k −1 ) in 10%−90% SOC.
Abstract: Understanding the entropy change (Δ S ) characteristics of Hard carbon ∣∣ Na 3 V 2 (PO 4 ) 3 full cell is crucial for its long cycle life and high safety. This work investigated the thermodynamic data of sodium ion half/full cells based on Na 3 V 2 (PO 4 ) 3 and hard carbon material. The results show that the trend of Δ S for Na ∣∣ Na 3 V 2 (PO 4 ) 3 exhibits great change at 0%–10% and 90%–100% SOCs (states of charge), and remains constant (≈−14.54 J·mol −1 ·k −1 ) in 10%–90% SOCs, which is consistent with the characteristics of two-phase reaction. Whereas the Δ S of Na ∣∣ hard carbon (HC) remains essentially constant (≈8.30 J·mol −1 ·k −1 ) in the most Na + concentration, fluctuating in the range of 3.17–11.71 J·mol −1 ·k −1 . Notably, Δ S shows a negative value (−6.09 J·mol −1 ·k −1 ) at x = 0.3 ( x in Na x C) and is close to 0 J·mol −1 ·k −1 at x = 1.0. The HC ∣∣ Na 3 V 2 (PO 4 ) 3 full cell entropy change is basically constant (≈−19.56 J·mol −1 ·k −1 ) in 10%–90% SOCs, and reaches a peak at 60% SOC (−10.75 J·mol −1 ·k −1 ), indicating the Δ S of full cell is mainly influenced by Na 3 V 2 (PO 4 ) 3 electrode. Based on thermodynamic entropy change characteristics, this work aims to provide a reliable reference to the storage, transportation, thermal management, and safety boundary for batteries.

Journal ArticleDOI
29 Dec 2022
TL;DR: In this paper , a consistent set of 46 group additive values (GAVs) and non-nearest neighbor interactions (NNIs) is determined for the standard enthalpy of formation, standard molar entropy, and heat capacity.
Abstract: Carbenium ions are important intermediates in both zeolite and plasma chemistry. The construction of kinetic models for zeolite and plasma chemistry requires the incorporation of thermodynamic properties of these carbenium ions. In this way, thermodynamic equilibrium is incorporated resulting in more accurate and general kinetic models, which facilitate rational zeolite design and plasma process development. In this work, a consistent set of 46 group additive values (GAVs) and non-nearest neighbor interactions (NNIs) is determined for the standard enthalpy of formation, standard molar entropy, and heat capacity. The GAVs are regressed based on 165 quantum chemistry calculations with the CBS-QB3 composite method for carbenium ions as CBS-QB3 was proven a valid method for carbenium property prediction. The presented group additive approach gives the first GAVs and NNIs for entropy and heat capacity and 33 novel values for enthalpy prediction. The determined non-nearest neighbor interactions account for the effect of longer range hyperconjugation, resonance stabilization, and inductive stabilization, which are shown to be crucial for the carbenium stability. The presented group additivity scheme ensures an accurate prediction of all properties with a mean absolute error of 4.82 kJ/mol, 4.92 J/(mol·K), and 1.95 J/(mol·K) for the standard enthalpy of formation, standard molar entropy, and heat capacity, respectively. The reported GAVs and NNIs ensure the thermodynamic property prediction of paraffinic, olefinic, alkynic, aromatic, and five- and six-ring naphthenic cations.



Journal ArticleDOI
18 Jan 2022-Entropy
TL;DR: In this paper , the molar heat capacity of solid formamidinium lead iodide (CH5N2PbI3) was measured over the temperature range from 5 to 357 K using a precise automated adiabatic calorimeter.
Abstract: In the present study, the molar heat capacity of solid formamidinium lead iodide (CH5N2PbI3) was measured over the temperature range from 5 to 357 K using a precise automated adiabatic calorimeter. In the above temperature interval, three distinct phase transitions were found in ranges from 49 to 56 K, from 110 to 178 K, and from 264 to 277 K. The standard thermodynamic functions of the studied perovskite, namely the heat capacity C°p(T), enthalpy [H0(T) − H0(0)], entropy S0(T), and [G°(T) − H°(0)]/T, were calculated for the temperature range from 0 to 345 K based on the experimental data. Herein, the results are discussed and compared with those available in the literature as measured by nonclassical methods.


Journal ArticleDOI
TL;DR: In this article , the micellization behavior of surfactant is investigated at three different temperatures (298.15, 308.15 and 318.15)K in presence of various concentrations (0.10, 0.25, and 0.50) mmolkg-1 of drug Betaine hydrochloride via conductivity measurements.
Abstract: Taking in consideration the application of surfactants in drug delivery, the interactions of cationic surfactant cetyltrimethylammonium bromide (CTAB) with drug Betaine Hydrochloride have been scrutinized. The micellization behaviour of surfactant is investigated at three different temperatures (298.15, 308.15, and 318.15)K in presence of various concentrations (0.10, 0.25, and 0.50) mmolkg-1 of drug Betaine hydrochloride via conductivity measurements The critical micelle concentration (CMC) attained though conductometric measurements has been utilized to obtain different thermodynamic parameters of micellization i.e. standard free energy of micellization (ΔG0 m), standard enthalpy of micellization (ΔH0 m), and standard entropy of micellization (ΔS0 m).


Journal ArticleDOI
01 Dec 2022
TL;DR: Differential scanning calorimetry (DSC) was used to measure the enthalpies of reaction for the dehydration of the potassium Tutton salts, K2M(SO4)2 . 6 H2O with M = Mg, Co, Ni, Cu and Zn as discussed by the authors .
Abstract: Differential scanning calorimetry (DSC) was used to measure the enthalpies of reaction for the dehydration of the potassium Tutton salts, K2M(SO4)2 . 6 H2O with M = Mg, Co, Ni, Cu and Zn. The values determined ranged from 335 kJ mol−1 for K2Mg(SO4)2 6 H2O to 355 kJ mol−1 for K2Ni(SO4)2. 6 H2O with a measured standard deviation of ± 5 kJ mol−1. Although the information needed to obtain precise values for the enthalpies of formation is not available in the literature for all of these salts, values calculated by modeling the amorphous dehydrated compound as an ideal solid solution produced values within 10 kJ mol−1 of the values determined for K2M(SO4)2. 6 H2O (M= Mg, Cu, and Zn) where the information needed for this calculate was available. DSC was also used to determine the entropies of reaction for the dehydration of these salts. Since there is little information about the entropies of these compounds in the literature, the entropies of reaction were used with the ideal solution model for the amorphous compound to estimate the standard molar entropies for these salts. The values determined ranged from 490 J K−1 mol−1 for K2Cu(SO4)2 . 6 H2O to 540 J K−1 mol−1 for K2Co(SO4)2 . 6 H2O. Since these values are based upon estimated values, they have an estimated error of ± 5 percent.


Journal ArticleDOI
TL;DR: In this article , the thermodynamic constants of disulfide (S22−) formation were measured by different techniques (potentiometry, spectrophotometry, chromatography) and the results showed that robust determination of K2 may be achieved at the molar ratio of S0 to S(II) ≤ 0.064.

Journal ArticleDOI
TL;DR: In this paper , the thermodynamic functions of germanium in alloys were determined by combining obtained data with the thermodynamics functions of GeTe, and the standard Gibbs free energy and enthalpy of formation, as well as the standard entropy of the GeBi2Te4, GeBi4Te7 and GeBi6Te10 compounds were calculated using these data.
Abstract: The GeBi2Te4-Bi2Te3-Te system was investigated by XRD and EMF measurements of the reversible concentration cell of the type (-) GeTe (solid) │glycerol +KCl │ Ge-Bi-Тe (solid) (+) in the 300-450K temperature range. It was shown that, in the indicated temperature range, elementary tellurium forms tie lines with all telluride phases of the system. Equations for the temperature dependencies of EMF in all phase regions have been obtained from the data of EMF measurements, from which the partial thermodynamic functions of GeTe in alloys have been calculated. The partial molar functions of germanium in alloys were determined by combining obtained data with the thermodynamic functions of GeTe. Standard Gibbs free energy and enthalpy of formation, as well as the standard entropy of the GeBi2Te4, GeBi4Te7, GeBi6Te10 compounds and solid solutions based on Bi2Te3 have been calculated using these data, solid-phase equilibrium diagram of the GeBi2Te4-Bi2Te3-Te system, and corresponding thermodynamic functions of Bi2Te3.

Journal ArticleDOI
TL;DR: In this article , the high-temperature heat capacity of BiSbO4 phase has been measured and is given in the form of Maier-Kelley equation.

Journal ArticleDOI
TL;DR: In this paper , the intermolecular interactions between ethanol (E-OH), cinnamaldehyde (CAD) with anionic surfactant sodium dodecyl sulfate (SDS) in nonaqueous media has been examined by utilizing conductometric and spectroscopic techniques.
Abstract: The study of intermolecular interactions between ethanol (E-OH), cinnamaldehyde (CAD) with anionic surfactant sodium dodecyl sulfate (SDS) in non-aqueous media has been examined by utilizing conductometric and spectroscopic techniques. The critical micelle concentration (CMC) values have been determined. The experimental conductance data were analyzed against temperature and concentration using standard relations. The pseudo phase separation model has been adopted to calculate various thermodynamic parameters like standard free energy, ∆G°mic, enthalpy, ∆H°mic, and entropy, ∆S°mic, of micelle formation. Fourier transforms infrared analysis (FTIR), and Fluorescence spectra were taken out to assess the possible interactions prevailing in the micellar systems. The findings demonstrated that the presence of SDS, and the composition of CAD + ethanol might affect the thermodynamic parameters. The discrepancy in these parameters with the surfactant concentration or with the temperature change indicates the manifestation of different interactions prevailing in the studied systems.

Journal ArticleDOI
TL;DR: In this paper , the stochastic properties of 3,3'-(2,2'-(4-methyl-phenylenesulfonamido)bis(ethane-2,1-diyl))bis(1-benzyl-3H-benzo[d]imidazol-1-ium)dibromide with Ni2+, Zn2+, Pd2+, Ag+, and Hg2+ cations in the binary mixture of methanol (MeOH) and water (H2O) at different temperatures (15, 25, 35 and 45ºC) were studied using a conductometric method.
Abstract: In this research, the determination and complexation process between 3,3'-(2,2'-(4-methyl-phenylenesulfonamido)bis(ethane-2,1-diyl))bis(1-benzyl-3H-benzo[d]imidazol-1-ium)dibromide with Ni2+, Zn2+, Pd2+, Ag+, and Hg2+ cations in the binary mixture of methanol (MeOH) and water (H2O) at different temperatures (15, 25, 35 and 45ºC) were studied using a conductometric method. The results show that the stoichiometry of the complexes in all binary mixed solvents for Ni2+, Zn2+, and Pd2+ were 1:1 (M:L), while in other cases 1:2 (M:L) and 2:1(M:L). The stability constants (log ) of complex formation have been determined by fitting molar conductivity curves using a computer program (GENPLOT). The obtained data shows that in the pure methanol solvent system, the stability order is Ni2+< Pd2+

Posted ContentDOI
19 Nov 2022
TL;DR: In this paper , a core-shell Fe 3 O 4 @Humic acid/montmorillonite nanocomposites were used for removing methyl orange dye from an aqueous solution.
Abstract: Abstract The current inquiry aimed at using core-shell Fe 3 O 4 @Humic acid/montmorillonite nanocomposites for removing methyl orange dye from an aqueous solution. The samples were characterized by FT-IR, TEM, SEM, XRD, BJH, and BET analytical methods. The efficiency removal has been utilized for 300 min reaction time using the response surface methodology by a design of five-factor-three-level central composite. The adsorption kinetics followed the pseudo-second-order rate kinetic model, showing an acceptable correlation (R 2 > 0.99). Langmuir, Freundlich, Temkin, Dubinin–RadushKevich, and Harkins–Jura isotherms were utilized for the analysis of the equilibrium data. Also, we have estimated standard Gibbs free energy (∆G°), standard enthalpy (∆H°), standard entropy (∆S°), and the activation energy (E a ). The findings of this investigation suggest that the absorption of methyl orange on the adsorbent pursues the Frondelich isothermal formulation. The ∆G° values obtained showed physical absorption in this adsorption process. ∆H° showed that the dye adsorption mechanism was endothermic, and ∆S° indicated an increase in irregularity and the probability of contact between methyl orange molecules and the adsorbent surface in the dye adsorption process. Positive Ea values pointed out the nature of the endothermic absorption process. S* value was minimal and close to zero, which established the process of physical absorption.