THE ENTROPIES OF IONS IN AQUEOUS SOLUTION: I. DEPENDENCE ON CHARGE AND RADIUS

1956 ◽  
Vol 34 (8) ◽  
pp. 1107-1113 ◽  
Author(s):  
K. J. Laidler
Keyword(s):  
Aqueous Solution ◽  
Free Volume ◽  
Linear Dependence ◽  
Empirical Equations ◽  
Entropy Changes ◽  
Absolute Scale ◽  
A Value ◽  
Born Equation ◽  
Charge And Radius ◽  
Electrostatic Theory

Empirical equations recently proposed for the entropies of ions in aqueous solution involve a linear dependence on the first power of the valency z and, in some cases, an inverse dependence on the square of a modified radius. Such relationships have no fundamental validity since the entropies are related arbitrarily to a zero value for the proton. It is shown that the entropy changes for reactions of various ionic types indicate that the entropy must depend on z2, as proposed by Born on the basis of simple electrostatic theory. When the entropies of monatomic ions are related to the absolute scale, in which the proton has a value of −5.5 e.u., they are found to vary linearly with z2/ru, where ru is the univalent radius defined by Pauling. The slope is found to be close to that predicted by the Born equation, and the non-electrostatic part of the entropy is shown to correspond to the movement of the ion in a free volume of 0.73 eu. Å.

THE PARTIAL MOLAL VOLUMES OF IONS IN AQUEOUS SOLUTION: I. DEPENDENCE ON CHARGE AND RADIUS

1956 ◽  
Vol 34 (9) ◽  
pp. 1209-1216 ◽  
Author(s):  
A. M. Couture ◽  
K. J. Laidler
Keyword(s):  
Ionic Crystal ◽  
Infinite Dilution ◽  
Hydrogen Ion ◽  
Empirical Equations ◽  
Density Data ◽  
A Value ◽  
Partial Molal Volumes ◽  
Solutions Of Electrolytes ◽  
Molal Volumes ◽  
Charge And Radius

The density data for aqueous solutions of electrolytes have been analyzed, and partial molal volumes at infinite dilution have been calculated. The values are shown to be additive, and a set of volumes for individual ions has been prepared, based arbitrarily on a value of zero for the hydrogen ion. It is shown that for a given value of the charge the volumes vary linearly with the cube of the ionic crystal radii, and for a given radius vary with the first power of the charge. In the case of cations the equation obeyed is[Formula: see text]while for anions[Formula: see text]If the volume of the hydrogen ion is taken as −6 ml. instead of zero the same equation is obeyed for both cations and anions, namely[Formula: see text]The empirical equations are discussed in terms of a simple model for ions in solution.

Ferricyanide Oxidation of Butanol Homogeneously Catalysed by Chlororuthenium Complexes

1979 ◽  
Vol 32 (9) ◽  
pp. 1905 ◽  
Author(s):  
AF Godfrey ◽  
JK Beattie
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Linear Dependence ◽  
Rate Constants ◽  
Homogeneous Catalyst ◽  
Basic Solution ◽  
Rate Law ◽  
Kinetics Of ◽  
Solution Estimates ◽  
Butanol Concentration

The oxidation of butan-1-ol by ferricyanide ion in alkaline aqueous solution is catalysed by solutions of ruthenium trichloride hydrate. The kinetics of the reaction has been reinvestigated and the data are consistent with the rate law -d[FeIII]/dt = [Ru](2k1k2 [BuOH] [FeIII])/(2k1 [BuOH]+k2 [FeIII]) This rate law is interpreted by a mechanism involving oxidation of butanol by the catalyst (k1) followed by reoxidation of the catalyst by ferricyanide (k2). The non-linear dependence of the rate on the butanol concentration is ascribed to the rate-determining, butanol-independent reoxidation of the catalyst, rather than to the saturation of complex formation between butanol and the catalyst as previously claimed. Absolute values of the rate constants could not be determined, because some of the ruthenium precipitates from basic solution. With K3RuCl6 as the source of a homogeneous catalyst solution, estimates were obtained at 30�0�C of k1 = 191. mol-1 s-1 and k2 = 1�4 × 103 l. mol-1 s-1.

scholarly journals Detection of Nitrate(NO-2) Ions Produced in Disproportionation of Nitrogen(II) Oxide in Aqueous Solution

2012 ◽  
Vol 19 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Aleksander Kufelnicki ◽  
Jolanta Jaciubek-Rosińska
Keyword(s):  
Aqueous Solution ◽  
Linear Dependence ◽  
Fluorescence Spectra ◽  
Detection Method ◽  
Measurement Range ◽  
Disproportionation Reaction ◽  
Nitrate Ions

Detection of Nitrate(NO-2) Ions Produced in Disproportionation of Nitrogen(II) Oxide in Aqueous Solution The nitrate ions (NO-2), products of disproportionation of NO in aqueous solution, were detected by an Orion Nitrite Electrode 97-46. Calibrations by means of standard NaNO2 solutions within the range 0.001÷100 ppm indicated linear dependence of EMF on ppm within 1÷100 ppm. Measurements justified the usefulness of this detection method of NO in solutions of OH- concentration lower than 10-2 mol dm-3 since at higher concentrations the EMF values exceeded the measurement range of the electrode. Occurrence of nitrate ions produced in the disproportionation reaction was additionally confirmed in dependence of OH- concentration by near UV and fluorescence spectra. The calibrated ion-selective nitrate electrode has also been shown, on the basis of Co(II)-dipeptide-OH- systems, as a useful tool in studying reversible NO uptake by Co(II) chelates in aqueous solution. Such a reaction may be regarded as simulating the harmful binding of NO by hemoglobin, where it substitutes the isoelectronic dioxygen.

THE ENTROPIES OF IONS IN AQUEOUS SOLUTION: II. AN EMPIRICAL EQUATION FOR OXY-ANIONS

1957 ◽  
Vol 35 (3) ◽  
pp. 202-206 ◽  
Author(s):  
A. M. Couture ◽  
K. J. Laidler
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Interatomic Distance ◽  
Empirical Equation ◽  
Central Atom ◽  
Van Der Waals ◽  
Empirical Relationship ◽  
Mean Deviation ◽  
A Value

The entropies of oxy-anions in aqueous solution are shown to obey the empirical relationship[Formula: see text]with a mean deviation of 3.6 e.u. In this equation [Formula: see text] is the entropy relative to a value of −5.5 e.u. for the proton, M is the molecular weight, z the number of charges on the ion, n the number of charge-bearing ligands, r is equal to r12 + 1.40, where r12 is the interatomic distance between the central atom and the surrounding oxygens, and 1.40 is the van der Waals radius of oxygen. The significance of the empirical equation is discussed.

scholarly journals The kinetics of mutarotation in solution

1940 ◽  
Vol 176 (966) ◽  
pp. 352-367 ◽  
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Reducing Sugars ◽  
Arrhenius Equation ◽  
Energy Of Activation ◽  
A Value ◽  
Temperature Ranges ◽  
Velocity Coefficient ◽  
Kinetics Of ◽  
True Energy

The kinetics of the mutarotation of representative reducing sugars from the pentose, hexose and disaccharide series have been investigated polarimetrically over wide temperature ranges in aqueous solution. The dependence of the velocity coefficient, k , upon temperature is fairly well reproduced by an equation of the form ln k = C + ( J/R ) ln T - E/RT . The true energy of activation, E , is found to be some 6000 calories greater than the apparent value afforded by the Arrhenius equation at room temperature. J/R has a value of — 10, which is identified as the number of oscillators contributing to the activation. The constants C, J and E of this equation are discussed, with reference to many reactions, in terms of a theory of unimolecular reactions in solution.

Calorimetric investigations of Al3+(aq), Al(OH)4−(aq), and aluminium–citrate complexes at 298.15 K

1997 ◽  
Vol 75 (8) ◽  
pp. 1110-1113 ◽  
Author(s):  
Ching-hsien Wu ◽  
Celina Dobrogowska ◽  
Xin Zhang ◽  
Loren G. Hepler
Keyword(s):  
Aqueous Solution ◽  
Aluminum Hydroxide ◽  
Equilibrium Constants ◽  
A Value ◽  
Calorimetric Measurements ◽  
Aluminum Complexes ◽  
Aluminium Citrate ◽  
Calorimetric Investigations ◽  
Citrate Ions

We have combined results of earlier measurements leading to equilibrium constants for formation and reaction of aluminum–citrate complexes in aqueous solution at 298.15 K with results of our calorimetric measurements at this same temperature to obtain ΔH values for reactions of Al3+(aq) with citrate ions. Results of some of these calorimetric measurements also lead to a value of ΔH for the reaction Al3+(aq) + 4 OH`(aq) = Al(OH)4−(aq). Keywords: aluminum hydroxide, Al(OH)4−(aq), thermodynamics; aluminium–citrate complexes, thermodynamics; citrate–aluminum complexes, thermodynamics; aluminum (3+, aq), thermodynamics.

scholarly journals Peculiarities of electro-erosion machining with discharge low-energy pulses

2017 ◽  
Vol 2 (9) ◽  
pp. 17-20 ◽  
Author(s):  
Юрий Моргунов ◽  
Yuryi Morgunov ◽  
Борис Саушкин ◽  
Boris Saushkin ◽  
Андрей Груздев ◽  
...  
Keyword(s):  
Linear Dependence ◽  
Pulse Energy ◽  
Geometric Parameters ◽  
Low Energy ◽  
A Value ◽  
Non Linear

The investigations of energetic characteristics of an erosion pulse and geometric parameters of single erosion dimples at the application of discharge low-energy pulses are carried out. A non-linear dependence of pulse energy upon its length under given conditions is shown. On the basis of the experiment results a value of the factor of electro-erosion workability for steel 12Ch18N10T is specified.

STUDIES ON DICYANOTRIAZOLE: I. THE CONDUCTANCE OF DILUTE AQUEOUS SOLUTIONS OF DICYANOTRIAZOLE AT 25 °C.

1942 ◽  
Vol 20b (8) ◽  
pp. 161-167 ◽  
Author(s):  
E. G. Taylor
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Dissociation Constant ◽  
Experimental Studies ◽  
Equivalent Conductance ◽  
A Value ◽  
Dilute Aqueous Solution ◽  
Dilute Aqueous Solutions

Previous experimental studies of dicyanotriazole have resulted in statements that the compound is an acid comparable in strength with the strong mineral acids.In the present work, measurements of the equivalent conductance of dicyanotriazole in dilute aqueous solution give the dissociation constant of the acid as 3.378 × 10−2 at 25 °C., thus showing it to be an acid possessing about the same strength as dichloracetic acid.The limiting equivalent conductance of dicyanotriazole at 25 °C. is 384.9. The earlier work gave a value of 397.44.

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