How Thermodynamic Data and Equilibrium Constants Changed When the Standard-State Pressure Became 1 Bar

1999 ◽  
Vol 76 (2) ◽  
pp. 212 ◽  
Author(s):  
Richard S. Treptow
Keyword(s):  
Thermodynamic Data ◽  
Equilibrium Constants ◽  
Standard State ◽  
State Pressure

Infrared Study of Acetic Acid Solutions in CCl4

1995 ◽  
Vol 60 (7) ◽  
pp. 1094-1100 ◽  
Author(s):  
Ivona Malijevská ◽  
Martin Polášek
Keyword(s):  
Acetic Acid ◽  
Regression Analysis ◽  
Carbon Tetrachloride ◽  
Room Temperature ◽  
Equilibrium Constants ◽  
Acid Solutions ◽  
Standard State ◽  
Infrared Study ◽  
Mean Values ◽  
Linear Dimer

Spectra of acetic acid solutions in carbon tetrachloride were taken at room temperature over the concentration range 0.025-0.00125 mol dm-3. Solutions of acetic acid were modelled as an ideal mixture of monomers, and cyclic and linear dimers. Regression analysis effected separation of the experimental envelope into its component bands. Band shapes were approximated by a Lorenzian function with the resolved band peak frequencies 1 712 cm-1 for the cyclic dimer, 1 724 cm-1 for the linear dimer and 1 765 cm-1 for the acetic acid monomer. Mean values of equilibrium constants for the standard state of unit concentration are 2 700 for the cyclic and 393 for the linear dimer, respectively.

The sorption of krypton and xenon in zeolites at high pressures and temperatures I. Chabazite

1972 ◽  
Vol 326 (1566) ◽  
pp. 315-330 ◽  
Keyword(s):  
Gas Phase ◽  
Thermodynamic Equilibrium ◽  
High Pressures ◽  
Equilibrium Constants ◽  
Standard State ◽  
Temperature Range ◽  
Thermodynamic Relationship ◽  
High Pressures And Temperatures

Isotherms of Kr and Xe in chabazite have been obtained for absolute sorption and for Gibbs excess sorption, in the temperature range 150 to 450 °C and at pressures up to 100 atm. Thermodynamic equilibrium constants for distribution of gas between the crystals and the gas phase, standard state concentrations and heats of sorption have been determined. At the highest pressures differences between absolute sorption and Gibbs excess sorption were large. The change of equilibrium fugacity with temperature for given absolute and Gibbs excess sorptions yielded two differential heats of sorption and two differential entropies of the sorbate. These heats, and the corresponding entropies, differed numerically and in their dependence upon amount sorbed. The thermodynamic relationship between the two heats has been derived and discussed.

THE DISSOCIATION OF α- AND β-LIPOVITELLIN IN AQUEOUS SOLUTION: PART I. EFFECT OF pH, TEMPERATURE, AND OTHER FACTORS

1962 ◽  
Vol 40 (3) ◽  
pp. 363-372 ◽  
Author(s):  
R. W. Burley ◽  
W. H. Cook
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Thermodynamic Data ◽  
Equilibrium Constants ◽  
Effect Of Ph ◽  
Reversible Dissociation ◽  
Lipoprotein Concentration ◽  
Irreversible Aggregation ◽  
Increasing Temperature

The effect of pH, temperature, ionic strength, and lipoprotein concentration on the reversible dissociation of α- and β-lipovitellin in aqueous solutions above pH 6 has been examined by ultracentrifugal measurements. Under otherwise similar conditions α- and β-lipovitellin are 50% dissociated at pH 10.5 and 7.8, respectively. Both lipovitellins undergo an irreversible aggregation above about pH 11; β-lipovitellin is sometimes converted to a non-dissociable form upon aging. Dissociation of both lipovitellins decreases with increasing ionic strength and increasing temperature. Although the ultracentrifugal method has limitations, provisional equilibrium constants and thermodynamic data were obtained from it that are comparable with those obtained for certain protein systems.

Apparent molar heat capacities and volumes of some aqueous solutions of aliphatic amino acids at 288.15, 298.15, 313.15, and 328.15 K

1994 ◽  
Vol 72 (2) ◽  
pp. 362-368 ◽  
Author(s):  
Andrew W. Hakin ◽  
Michelle M. Duke ◽  
Sheri A. Klassen ◽  
Robert M. McKay ◽  
Kathryn E. Preuss
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Equilibrium Constants ◽  
Heat Capacities ◽  
Apparent Molar Volumes ◽  
Protein Chemistry ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Molar Volumes

The thermodynamics of amino acid systems are key to the understanding of protein chemistry. We have found that many previous studies of the apparent molar volumes and heat capacities of aqueous solutions of amino acids were conducted at the standard temperature of 298.15 K. This does not allow for the fact that most biological processes occur at temperatures removed from this standard condition.In an attempt to address this imbalance we have measured densities and heat capacities for aqueous solutions of glycine, L-alanine, L-serine, and L-threonine at 288.15, 298.15, 313.15, and 328.15 K using a Picker flow microcalorimeter. Apparent molar volumes and heat capacities, and the associated standard state partial molar properties have been calculated. Constant pressure variations of revised Helgeson, Kirkham, and Flowers equations have been fitted to calculated standard state volumes and heat capacities over the temperature range 288.15 to 328.15 K. These equations may be used to estimate standard state volumes and heat capacities, and hence equilibrium constants, for aqueous amino acid systems at higher temperatures.

scholarly journals Beiträge zur Chemie des Phosphors, 139 [1] Triethyl-cyclotriphosphan, Trimethyl-cyclotriphosphan; Gleichgewichte zwischen Cyclophosphanen (PR)n bei erhöhten Temperaturen/Contributions to the Chemistry of Phosphorus, 139 [1] Triethylcyclotriphosphane, Trimethylcyclotriphosphane; Equilibria between Cyclophosphanes (PR)n at Elevated Temperatures

1984 ◽  
Vol 39 (4) ◽  
pp. 438-444 ◽  
Author(s):  
Marianne Baudler ◽  
Josef Hahn ◽  
Erwin Clef
Keyword(s):  
Thermodynamic Equilibrium ◽  
Thermodynamic Data ◽  
Elevated Temperatures ◽  
Equilibrium Constants ◽  
Fractional Distillation ◽  
Ring Strain ◽  
Product Mixture

Triethylcyclotriphosphane, (PEt)3 (1), has been generated by thermolysis of tetraethylcyclotetraphosphane, (PEt)4. 1 can be obtained as a 43% solution in 1,2,3-triethyl-1,2,3-triphosphole, (PEt)3C2H2 (3), by fractional distillation of the product mixture formed in the reaction of K2(PEt)4 with ClHC=CHCl. 3 has been isolated and fully characterized. Furthermore 1 as well as (PMe)3 (2) and (PPh)3 exist besides (PR)4 (R = Et, Me, Ph) in thermodynamic equilibrium with (PR)5 at elevated temperatures; for R = Ph(PPh)6 is also formed. The thermodynamic data of the reactions 3/5 (PMe)5 ⇌ (PMe)3 and 4/5 (PMe)5 ⇌ (PMe)4 have been calculated from the equilibrium constants between 60 and 160 °C. The ring strain of 2 is much smaller than that of cyclopropane but increases with increasing size and bulk of the substituents R at the phosphorus threemembered ring.

Standard-state pressure

1984 ◽  
Vol 5 (2) ◽  
pp. 132-132
Author(s):  
L. H. Bennett
Keyword(s):  
Standard State ◽  
State Pressure

The aqueous chemistry of tellurium: critically-selected equilibrium constants for the low-molecular-weight inorganic species

2019 ◽  
Vol 16 (4) ◽  
pp. 289 ◽  
Author(s):  
Montserrat Filella ◽  
Peter M. May
Keyword(s):  
Molecular Weight ◽  
Aqueous Solutions ◽  
Thermodynamic Data ◽  
Equilibrium Constants ◽  
Computer Programs ◽  
Experimental Investigations ◽  
Low Molecular Weight ◽  
Aqueous Chemistry ◽  
Scientific Disciplines ◽  
Inorganic Species

Environmental contextEquilibrium constants are required in many scientific disciplines such as biology, medicine, engineering, and in particular chemistry. Lack of reliable equilibrium constants for tellurium has restricted our understanding of its speciation and behaviour in the environment. This study presents a reliable set of equilibrium constants for tellurium, thereby providing a more coherent basis for future experimental investigations of the geochemistry, biochemistry and toxicology of this element. AbstractRelatively little information is available in the literature regarding the speciation and solubility of tellurium in aqueous solutions. The available thermodynamic data have been critically evaluated and entered into a thermodynamic database. The Joint Expert Speciation System suite of computer programs has been used to achieve thermodynamic consistency and provide a critically-selected set of equilibrium constants that can later be used for modelling purposes.

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