scholarly journals Appendix 4 Standard Gibbs Energies and Enthalpies of Formation at 298 K, 1 atm, pH 7, and 0.25 M Ionic Strength

2015 ◽  
pp. 465-466
Keyword(s):  
Ionic Strength ◽  
Enthalpies Of Formation ◽  
Gibbs Energies

scholarly journals Thermochemical study of sodium and sodium-calcium amphibols

2019 ◽  
Vol 64 (5) ◽  
pp. 520-528
Author(s):  
L. P. Ogorodova ◽  
I. A. Kiseleva ◽  
M. F. Vigasina ◽  
Yu. D. Gritsenko ◽  
I. A. Bryzgalov ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Solution Calorimetry ◽  
Enthalpies Of Formation ◽  
Thermochemical Study ◽  
Massif Central ◽  
Calvet Microcalorimeter ◽  
Gibbs Energies ◽  
Sodium Calcium ◽  
Isomorphic Series ◽  
End Members

A thermochemical study of six natural sodium and sodium-calcium amphiboles was carried out using the high-temperature melt solution calorimetry on a Tian-Calvet microcalorimeter. The enthalpies of formation from the elements have been obtained for arfvedsonites: K0.5(Na1.5Ca0.5)(Mg4.0Fe0.93+Al0.1)[Si8.0O22](OH)2 (Inaglinsky Massif, Central Aldan, Russia) (-11626.6 ± 8.9 kJ/mol), (Na0.5K0.1)(Na1.6Ca0.4)(Mg3.6Fe0.42+Fe0.83+Al0.2)[Si8.0O22](OH)2 (Khibiny Massif, Kola Peninsula, Russia) (-11520.8 ± 14.6 kJ/mol) and (Na0.7K0.3)Na2.0(Fe4.02+Fe0.63+Mn0.1Ti0.1Al0.2)[Si8.0O22](OH)2 (Katuginskoe deposit, Transbaikalia, Russia) (-11384.7 ± 17.1 kJ/mol); for riebeckites: Na2.0(Mg2.5Fe0.52+Fe1.53+Al0.5)Si8O22(OH)2 (Kumula deposit, Central Kazakhstan) (-10791.0 ± 10.1 kJ/mol) and Na2.0(Mg0.9Fe2.12+Fe1.93+Al0.1)[Si8O22](OH)2 (Krivoy Rog, Ukraine) (-10260.8 ± 10.9 kJ/mol) and richterite (Na0.7K0.3)(Ca1.2Na0.8)(Mg4.6Fe0.42+)[Si7.8Al0.2O22](OH)2 (Kovdorsky Massif, Kola Peninsula, Russia) (-12154.2 ± 9.7 kJ/mol). The values of the standard entropies, enthalpies, and Gibbs energies of formation are estimated for the end members of isomorphic series: arfvedsonite – magnesioarfvedsonite, riebeckite – magnesioriebeckite and richterite – ferrochichthite.

scholarly journals Thermodynamic properties of fluorapophyllite-(k) and hydroxylapophyllite-(k)

2019 ◽  
Vol 64 (7) ◽  
pp. 726-732
Author(s):  
L. P. Ogorodova ◽  
L. V. Melchakova ◽  
M. F. Vigasina ◽  
Yu. D. Grytsenko ◽  
D. A. Ksenofontov ◽  
...  
Keyword(s):  
Heat Flux ◽  
High Temperature ◽  
Thermodynamic Properties ◽  
Solution Calorimetry ◽  
Enthalpies Of Formation ◽  
Thermochemical Study ◽  
Gibbs Energies ◽  
Natural Minerals ◽  
Temperature Heat

Thermochemical study of natural minerals of the apophyllite group: fluorapophyllite-(K) KCa4[Si8O20]F . 8H2O (Maharashtra, India) (I) and hydroxylapophyllite-(K) KCa4[Si8O20]OH . 8H2O (Norilsk, Russia) (II) were performed on a high-temperature heat-flux microcalorimeter Tian–Calvet “Setaram” (France) using the melt solution calorimetry method. The first data on the enthalpies of formation from the elements for the minerals studied are obtained: -13 205±13 kJ/mol (I) and -13 054±20 kJ/mol (II). The values of their standard entropies and Gibbs energies of formation are estimated.

scholarly journals Thermodynamic properties of human tissues

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 4115-4133 ◽  
Author(s):  
Marko Popovic ◽  
Mirjana Minceva
Keyword(s):  
Heat Capacity ◽  
Gibbs Energy ◽  
Soft Tissues ◽  
Constant Pressure ◽  
Enthalpies Of Formation ◽  
Human Tissues ◽  
Empirical Formulas ◽  
Average Value ◽  
Gibbs Energies ◽  
Constituent Elements

This paper reports empirical formulas, enthalpies of formation, molar entropies, Gibbs energies of formation, and molar heat capacities at 25?C and 37?C for human soft tissues. The results show that Gibbs energy, except for certain tissues (adipose), is relatively low compared with the constituent elements, the average value being ?17.57 kJ/C-mol. The average constant pressure heat capacity of hydrated human body soft tissues is 3.24 J/gK in agreement with other data in the literature.

scholarly journals The interaction between β-lactoglobulin and sodium N-dodecyl sulphate

1976 ◽  
Vol 153 (3) ◽  
pp. 713-718 ◽  
Author(s):  
M N Jones ◽  
A Wilkinson
Keyword(s):  
Ionic Strength ◽  
Equilibrium Dialysis ◽  
Protein Molecule ◽  
Enthalpies Of Formation ◽  
Enthalpy Of Interaction ◽  
Surfactant Anion ◽  
Ionic Nature ◽  
Ph Range ◽  
Low Ionic Strength ◽  
Β Lactoglobulin

1. The binding of sodium n-dodecyl sulphate to β-lactoglobulin was studied in the pH range 3.5-7.0 by equilibrium dialysis, ultracentrifugation and microcalorimetry. 2. At low binding concentrations (less than 30 bound surfactants anions per protein molecule) the complexes formed aggregates in solution. 3. At higher binding concentrations aggregation does not occur at low ionic strength (0.01 mol/litre), but continues at high ionic strength (0.1 mol/litre). 4. At 25 degrees C the enthalpy of interaction of sodium n-dodecyl sulphate with β-lactoglobulin can be interpreted as the sum of the enthalpies of formation of a complex with 2 bound surfactant anions, with an enthalpy change of -9.5 kJ-mol-1 of bound surfactant, and complexes containing at least 22 bound surfactant anions, with limiting enthalpies per bound surfactant anion of -12.4 kJ-mol-1 at pH 3.5 and -3.25 kJ-mol-1 at pH 5.5. 5. The binding of surfactant and the enthalpy of interaction at pH 3.5 ARE NOT SIGNIFICANTLY AFFECTED BY THE ADDITION Of 8 M-urea. 6. The data indicate that at low binding concentrations the interaction is of an ionic nature, and is accompanied by a conformational change in the protein.

scholarly journals STANDARD FORMATION ENTHALPIES OF HYDROXYETHYLIDENEDIPHOSPHONIC ACID AND PRODUCTS OF ITS DISSOCIATION IN AQUEOUS SOLUTION

2018 ◽  
Vol 61 (4-5) ◽  
pp. 37
Author(s):  
Alexander I. Lytkin ◽  
Viktor V. Chernikov ◽  
Olga N. Krutova ◽  
Ivan A. Skvortsov
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Enthalpies Of Formation ◽  
Formation Enthalpies ◽  
Different Temperatures ◽  
Heat Value ◽  
Standard Enthalpies Of Formation ◽  
Changes Over Time ◽  
Stepwise Dissociation

This study aimed the measuring the standard enthalpies of formation of hydroxyethylidenediphosphonic acid and the products of its dissociation in aqueous solutions at 298.15 K. In the literature there is a large amount of data on the constants of stepwise dissociation of the acid. The works were done at different temperatures and the values of the ionic strength of the solution on the background of the different nature of the supporting electrolytes. In order to compare the values of the constants of stepwise dissociation of the acid, obtained by different authors, we recalculated the values of рK1, рK2, рK3, рК4, рК5 at zero ionic strength by the Davies equation. The most probable values of thermodynamic constants of dissociation of hydroxyethylidenediphosphonic acid were the following: рК10 = 1.7±0.03; рК20 = 2.47±0.05; рК30 = 7.78±0.05; рК40 = 10.29±0.05 and pK50 = 11.13±0.05. Calorimetric measurements were performed on an ampoule calorimeter equipped with an isothermal shell and a KMT-14 thermistor temperature sensor, and the automatic recording the temperature changes over time. The operation of installation was verified with the integral enthalpies of dissolution in water of crystalline potassium chloride and was considered suitable for measurements, if certain it ∆solН298.15 (KCl ∞ H2O)=17.234± 0.018 kJ/mol, corresponding to the standard SRM 1655NBS. The heat value of the calorimeter water was 87±12 Дж/mol virtually coincided with the thermal value of the calorimeter for potassium hydroxide. The volume of the calorimetric liquid was 43.12 ml. The hydroxyethylidenediphosphonic acid samples were weighed on a VLR-200 balance with 2∙10-4 g accuracy. The confidence range of the average ΔН value was determined at 0.95 probability. The equilibrium compositions of solutions were calculated using RRSU software. The standard enthalpies of formation of hydroxyethylidenediphosphonic acid and the products of its dissociation in aqueous solutions were calculated.Forcitation:Lytkin A.I., Chernikov V.V., Krutova O.N., Skvortsov I.A. Standard formation enthalpies of hydroxyethylidenediphosphonic acid and products of its dissociation in aqueous solution. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 4-5. P. 37-42

Sign in / Sign up

Export Citation Format

Share Document