Thermodynamics of the dissociation of trans-cinnamic acid

1976 ◽  
Vol 54 (12) ◽  
pp. 1916-1917 ◽  
Author(s):  
Rebati Charan Das ◽  
Upendra Nath Dash ◽  
Kshama Nidhi Panda
Keyword(s):  
Free Energy ◽  
Dissociation Constant ◽  
Temperature Coefficient ◽  
Cinnamic Acid ◽  
Standard Enthalpy ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Dissociation Process ◽  
A Cell ◽  
Junction Potential

The dissociation constant of trans-cinnamic acid in water has been determined at 15, 20, 25, 30, 35, 40, and 45 °C using a cell without liquid junction potential. From the temperature coefficient of the dissociation constant, the standard enthalpy, entropy, and free energy changes of the dissociation process have been calculated.

Comparison of the free energy of transfer of electrolytes, measured with cells without transference, with the sum of the free energies of the corresponding cations and anions with the Owen-cell on standard conditions

1983 ◽  
Vol 36 (10) ◽  
pp. 1997 ◽  
Author(s):  
K Schwabe ◽  
W Hoffmann ◽  
C Queck
Keyword(s):  
Free Energy ◽  
Free Energies ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Ph Values ◽  
Liquid Junction Potentials ◽  
Free Energy Of Transfer ◽  
Energy Of Transfer ◽  
Very High ◽  
Junction Potential

The comparison of S2ΔS1G°tr(E1) with the sum of the values for the corresponding cation and anion S2ΔS1G°tr(Ct+)~S2ΔS1G°tr(X-) (measured) with Owen cells, gained by double extrapolation and by the assumption that the liquid junction potential at 1→0 may be neglected) gives values which differ by not more than ±5%. Most of the investigated acids allow the conclusion that the pH values, measured in cells with transference, and having the same electrodes, give good information on the acidity of the organic solvent and its water mixtures, referred to the standard state in water. That means that the pH, changed to the same H+ concentration in the solvent compared with that in water, is essentially an effect of the free energy of transfer of the hydrogen ion and not of very high liquid junction potentials.

Evaluation of Ionic and Solvent Components of the Liquid-Junction Potential Between Aqueous and Several Aquo-Organic Solutions

1994 ◽  
Vol 47 (5) ◽  
pp. 921 ◽  
Author(s):  
C Kahanda ◽  
O Popovych
Keyword(s):  
Mixed Solvent ◽  
Approximate Equation ◽  
Transport Numbers ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Solvated Ions ◽  
A Cell ◽  
Solvent Component ◽  
Organic Solutions ◽  
Junction Potential

Values of Ej,ion, the ionic component of the liquid-junction potential Ej, were calculated for the HCl,H2O |HCl,S2 and KCl,H2O | KCl,S2 junctions, where S2 was EtOH-H2O, HCONMe2- H2O and Me2SO-H2O solvents, and for the AgNO3,H2O | AgNO3,MeCN-H2O junction, over the entire mixed-solvent ranges. Both the old approximate equation for Ej,ion and our improved equation, which accounts for the variation of the ionic transport numbers t and chemical potentials Go in the interphase region, were used. Significant differences between the two equations were observed for systems where the t and ΔtG° functions dnisplayed extrema against the mixed-solvent composition. The highest Ej,ion value was 395 mV, for the HCl,H2O | HCl,Me2SO junction. Values of Ej,s,the solvent component of Ej, were calculated by subtracting the corresponding Ej,ion values from the total Ej, which was evaluated in each case from the e.m.f , of a cell with the liquid junction of interest and the transfer activity coefficient of the electroactive ion, estimated by the tetraphenylborate assumption. The magnitude of Ej,s was significant for the junctions between H2O and most of the solvents, and was particularly large for those involving dipolar aprotic solvents and highly solvated ions. The maximum Ej,s value was -201 mV, observed for the junction HCl,H2O|HCl,100% Me2SO.

scholarly journals Electrodiffusion Phenomena in Neuroscience and the Nernst–Planck–Poisson Equations

Electrochem ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 197-215
Author(s):  
Jerzy J. Jasielec
Keyword(s):  
Electrical Potential ◽  
Signal Propagation ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Patch Clamp Technique ◽  
Poisson Equations ◽  
Cellular Environment ◽  
Electrochemical Transport ◽  
Insight Into ◽  
Junction Potential

This work is aimed to give an electrochemical insight into the ionic transport phenomena in the cellular environment of organized brain tissue. The Nernst–Planck–Poisson (NPP) model is presented, and its applications in the description of electrodiffusion phenomena relevant in nanoscale neurophysiology are reviewed. These phenomena include: the signal propagation in neurons, the liquid junction potential in extracellular space, electrochemical transport in ion channels, the electrical potential distortions invisible to patch-clamp technique, and calcium transport through mitochondrial membrane. The limitations, as well as the extensions of the NPP model that allow us to overcome these limitations, are also discussed.

scholarly journals Liquid Junction Potential in Potentiometric Titrations. 5. Deduction of the Potential Functions for E.M.F. Cells with Complex Formation and with Liquid Junctions of the Type AY|AY+ BYz(B) + HY + AyL.

1999 ◽  
Vol 53 ◽  
pp. 314-319 ◽  
Author(s):  
Erzsébet Néher-Neumann ◽  
G. Voyiatzis ◽  
T. Østvold ◽  
Tapani A. Pakkanen ◽  
Markku Ahlgrén ◽  
...  
Keyword(s):  
Complex Formation ◽  
Potential Functions ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Potentiometric Titrations ◽  
Junction Potential

An Improved Equation for the Liquid Junction Potential at the Interface of Different Solvents

1992 ◽  
Vol 45 (10) ◽  
pp. 1633 ◽  
Author(s):  
A Berne ◽  
C Kahanda ◽  
O Popovych
Keyword(s):  
Mixed Solvent ◽  
Electrolyte Solutions ◽  
Transport Numbers ◽  
Liquid Junction Potential ◽  
Aqueous Methanol ◽  
Liquid Junction ◽  
Chemical Potentials ◽  
Solvent Dependence ◽  
New Equation ◽  
Junction Potential

The component of the liquid-junction potential due to the diffusion of ions across an interface of electrolyte solutions in different solvents was formulated by taking into account the solvent dependence of the transport numbers, t, and of the chemical potentials of ions in the interphase region as determined from experimental data on their variation in the mixed-solvent compositions. The new equation was applied to NaCl/NaCl and HCl/HCl junctions between water and methanol-water solvents over the entire solvent range. Significant differences between the results obtained with the new equation and the old formulation, which treated the transport numbers as solvent-independent, were observed only for the HCl junctions involving 90-100 wt % aqueous methanol, where tH exhibits a sharp minimum as a function of the solvent composition.

Ion-selective electrodes for sodium and potassium: a new problem of what is measured and what should be reported.

1985 ◽  
Vol 31 (3) ◽  
pp. 482-485 ◽  
Author(s):  
A H Maas ◽  
O Siggaard-Andersen ◽  
H F Weisberg ◽  
W G Zijlstra
Keyword(s):  
Activity Coefficient ◽  
Theoretical Calculations ◽  
Pair Formation ◽  
Ion Selective Electrodes ◽  
Residual Liquid ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Normal Plasma ◽  
Sodium And Potassium ◽  
Junction Potential

Abstract For clinical purposes the activities of Na+ and K+ obtained with ion-selective electrodes in undiluted whole blood or serum should be multiplied by an appropriate factor to obtain the same values as the substance concentrations obtained by flame photometry. The factor is primarily dependent on the mass concentration of water in normal plasma divided by the molal activity coefficient of Na+ (or K+) of normal plasma. We discuss the value of the molal activity coefficient of Na+ obtained by theoretical calculations and by direct measurement. The discrepancies between theory and measurement (gamma Na+ of 0.747 and 0.73, respectively) may be due to some binding of Na+ (protein binding or ion pair formation), a small and variable residual liquid-junction potential, or certainty about the appropriate value for the ionic strength of normal plasma (0.16 mol/kg or somewhat higher).

Theoretical investigation on the liquid junction potential in a slit-like microchannel

2004 ◽  
Vol 566 (2) ◽  
pp. 331-340 ◽  
Author(s):  
Kwan Hyoung Kang ◽  
In Seok Kang
Keyword(s):  
Theoretical Investigation ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Junction Potential

Liquid junction potential between different solvents

1990 ◽  
Vol 283 (1-2) ◽  
pp. 435-440 ◽  
Author(s):  
Kosuke Izutsu ◽  
Toshio Nakamura ◽  
Mitsuo Muramatsu
Keyword(s):  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Junction Potential
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