scholarly journals XI. Heats of dilution of concentrated solutions

1915 ◽  
Vol 215 (523-537) ◽  
pp. 319-351 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Specific Heat ◽  
Final Concentration ◽  
Dilute Solution ◽  
Dilute Solutions ◽  
Concentrated Solutions ◽  
Specific Heats ◽  
Thermal Change ◽  
Heats Of Dilution ◽  
Concentrated Solution

Heats of dilution have been exhaustively studied by Prof. Julius Thomsen for a very large number of aqueous solutions.* His method chiefly consisted in taking some concentrated solution and diluting it considerably. The total amount of heat generated or absorbed in this process was thus found and quoted against the final concentration expressed in molecules of water to one molecule of solute. It is to be noted that during the process of dilution most of the thermal change occurs in the early stages, and that after the first ten molecules of water are added the total heat generated or absorbed increases but slightly. The probable reason for this procedure is, that the experimenter finishes the operation with a dilute solution, so that starting with various initial concentrations, he may need only a few specific heats of certain dilute solutions. It must be remembered that only the final .specific heat of the solution need be known in order to measure the heat generated.

scholarly journals IX.—On the Relationship between Concentration and Electrolytic Conductivity in Concentrated Aqueous Solutions

1906 ◽  
Vol 45 (1) ◽  
pp. 241-259 ◽  
Author(s):  
John Gibson
Keyword(s):  
Aqueous Solutions ◽  
General Relationship ◽  
Electrolytic Conductivity ◽  
Dilute Solutions ◽  
Concentrated Solutions ◽  
Concentrated Aqueous Solutions ◽  
Solutions Of Electrolytes ◽  
Weak Electrolytes ◽  
The Relationship

Although great advances have been made during the last thirty years in our knowledge of dilute solutions, there has been no corresponding advance in respect of concentrated solutions. This is primarily due to the fact that hitherto no simple and general relationship has been discovered between the conductivity and the concentration of concentrated solutions of electrolytes. Ostwald's law of dilution holds only for dilute solutions of weak electrolytes, and the formulæ of Rudolphi and Van T'Hoff are applicable only to dilute solutions of good electrolytes. It seems therefore important to inquire whether the difficulty may not be to some extent overcome by an alteration in the mode of representing the facts.

Chaleur de dilution de solutions aqueuses d'acide polyacrylique, de son sel de sodium et de l'acide propionique

1971 ◽  
Vol 49 (24) ◽  
pp. 3935-3939 ◽  
Author(s):  
Jean-Pierre Cartier ◽  
Hubert Daoust
Keyword(s):  
Aqueous Solutions ◽  
Propionic Acid ◽  
Polyacrylic Acid ◽  
Sodium Polyacrylate ◽  
Heat Of Dilution ◽  
Concentrated Solutions ◽  
Sodium Salts ◽  
Structure Of Water ◽  
Calvet Microcalorimeter ◽  
Heats Of Dilution

With a Tian–Calvet microcalorimeter, heats of dilution at 25 °C have been measured for aqueous and acid (0.2 N HCl) solutions of polyacrylic acid and of propionic acid, and for aqueous solutions of the sodium salts of polyacrylic acid. The results are interpreted in terms of the change in structure of water resulting from the lengthening of the solute molecule. The heat of dilution of moderately concentrated solutions of sodium polyacrylate can be explained by the theory of Eigen and Wicke.

The reactions of hydrazines with trans-Dichlorobis(ethylenediamine)cobalt(III)chloride, and the isolation and kinetic studies of a Chlorobis(ethylenediamine)methylhydrazinecobalt(III) isomer

1973 ◽  
Vol 26 (9) ◽  
pp. 1923 ◽  
Author(s):  
SC Chan ◽  
CK Lee
Keyword(s):  
Electron Transfer ◽  
Kinetic Studies ◽  
Intramolecular Electron Transfer ◽  
Dilute Solution ◽  
Dilute Solutions ◽  
Spectroscopic Observations ◽  
Acid And Base ◽  
Concentrated Solution ◽  
Kinetics Of ◽  
Hydrolysis Of

The reactions of hydrazine, methylhydrazine, and 1,1-dimethylhydrazine with trans-dichlorobis(ethylenediamine)cobalt(III) chloride in concentrated and dilute solutions are studied. In concentrated solution, there is a reduction by hydrazine to form the insoluble polymeric [CoII(N2H4)2Cl2]n, a substitution by methylhydrazine to form chlorobis(ethylenediamine)methylhydrazinecobalt(III) chloride, and a disproportionation with 1,1-dimethylhydrazine to form tris(ethylenediamine)cobalt(III) chloride. In dilute solution, the reaction observed is a hydroxide substitution by hydrolysis of 1,1- dimethylhydrazine, a reduction to soluble cobalt(II)-ethylenediamine species with hydrazine, and a mixture of both processes for methylhydrazine. The chlorobis(ethylenediamine)methylhydrazinecobalt-(III) chloride obtained is a new complex, and is assigned a cis configuration on the basis of spectroscopic observations. The kinetics of its intramolecular electron-transfer, as well as its acid and base hydrolyses are also studied.

Changes of Dynamic Viscoelastic Properties of Tamarind Gum Aqueous Solutions

2011 ◽  
Vol 239-242 ◽  
pp. 477-480 ◽  
Author(s):  
Wancheng Sittikijyothin
Keyword(s):  
Aqueous Solutions ◽  
Viscoelastic Properties ◽  
Sample Solution ◽  
Effect Of Temperature ◽  
Dilute Solution ◽  
Tamarindus Indica ◽  
Typical Shape ◽  
Concentrated Solution ◽  
Mechanical Spectra

Tamarind gum was obtained from the seeds of Tamarindus indica. It was rich in polysaccharide (79.96%) and protein (13.46%) contents. In this work, the dynamic viscoelastic properties of tamarind gum aqueous solutions were investigated with a Haake Rheometer RS75 as a function of gum concentration and temperature. Four types of sample solution systems: a dilute solution, a concentrated solution, a weak gelled system, and a gelled like system were observed. The effect of concentration showed that the typical shape of the mechanical spectra for the dilute solution occurred for 2.30 wt% and the gelled like behaviour arose for the higher concentration (≥7.05 wt%) as measured at 25°C. While the effect of temperature on the dynamic viscoelastic properties of tamarind gum solution (6.91wt%) showed that the gum solution behaved the weak gelled system (25°C) and subsequently gelled like system (≥30°C).

III.—The Absorption of Light by Inorganic Salts. No. VII.: Aqueous Solutions of Iron Salts

1914 ◽  
Vol 33 ◽  
pp. 35-43 ◽  
Author(s):  
John S. Anderson
Keyword(s):  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Ferric Chloride ◽  
Inorganic Salts ◽  
Dilute Solutions ◽  
Concentrated Solutions ◽  
Quantitative Measurements ◽  
Iron Salts ◽  
Absorption Of Light

The absorption spectra of aqueous solutions of ferric chloride have been examined qualitatively by Jones and Anderson, and quantitatively by Ewan, but Ewan's measurements were confined to very dilute solutions. It was thought, therefore, that quantitative measurements might profitably be carried out on more concentrated solutions of ferric chloride and on solutions of other salts of iron.

Molecular Transformations in DNA under the Influence of UV-radiation

2020 ◽  
Vol 04 ◽  
Author(s):  
Vigen G. Barkhudaryan ◽  
Gayane V. Ananyan ◽  
Nelli H. Karapetyan
Keyword(s):  
Uv Radiation ◽  
Uv Irradiation ◽  
Absorption Spectroscopy ◽  
Calf Thymus Dna ◽  
Dilute Solutions ◽  
Concentrated Solutions ◽  
Buffer Solution ◽  
Low Concentration ◽  
Calf Thymus ◽  
Dna Solutions

Background: The processes of destruction and crosslinking of macromolecules occur simultaneously under the influence of ultraviolet (UV) radiation in synthetic polymers, dry DNA and their concentrated solutions. Objective: The effect of UV radiation on calf thymus DNA in dilute solutions subjected to UV- irradiation was studied in this work. Method: The calf thymus DNA was studied in dilute solutions using viscometry, absorption spectroscopy and electrophoresis. Results: It was shown, that at a low concentration of DNA in the buffer solution ([DNA] = 85 μg / ml) under the influence of UV radiation, the processes of destruction of macromolecules and an increase in their flexibility predominate, which is accompanied by a gradual decrease in the viscosity of their solution. In addition, due to the low concentration of the solution, intramolecular crosslinking of macromolecules predominates, which also reduces their size and, consequently, the viscosity of the solution. Conclusion: It was concluded, that in dilute DNA solutions, due to the predominance of the processes of intramolecular crosslinking of macromolecules over intermolecular, only constant processes of decreasing the sizes of DNA macromolecules occur. As a result, its solubility remains virtually unchanged during UV irradiation. The described comments are also excellently confirmed by the results of absorption spectroscopy and electrophoresis

Viscosity, electrical conductivity and density of the system ammonium nitrate-dimethyl sulphoxide

1984 ◽  
Vol 49 (5) ◽  
pp. 1109-1115
Author(s):  
Jindřich Novák ◽  
Zdeněk Kodejš ◽  
Ivo Sláma
Keyword(s):  
Electrical Conductivity ◽  
Aqueous Solutions ◽  
Ammonium Nitrate ◽  
Transport Properties ◽  
Calcium Nitrate ◽  
Dimethyl Sulphoxide ◽  
Present System ◽  
Empirical Equations ◽  
Concentrated Solutions ◽  
Nitrate Solutions

The density, viscosity, and electrical conductivity of highly concentrated solutions of ammonium nitrate in dimethyl sulphoxide have been determined over the temperature range 10-60 °C and the concentration range 7-50 mol% of the salt. The variations in the quantities as a function of temperature and concentration have been correlated by empirical equations. A comparison is made between the transport properties for the present system, aqueous solutions of ammonium nitrate, and calcium nitrate solutions in dimethyl sulphoxide.

The specific heats of three paramagnetic salts at very low temperatures

1956 ◽  
Vol 237 (1210) ◽  
pp. 395-403 ◽  
Keyword(s):  
Specific Heat ◽  
Absolute Temperature ◽  
Magnesium Nitrate ◽  
Paramagnetic Resonance ◽  
Specific Heats ◽  
Ammonium Alum ◽  
Relaxation Measurements ◽  
Ferric Ammonium ◽  
The Absolute ◽  
Measured Specific Heat

The specific heats of three paramagnetic salts, neodymium magnesium nitrate, manganous ammonium sulphate and ferric ammonium alum, have been measured at temperatures below 1°K using the method of γ -ray heating. The temperature measurements were made in the first instance in terms of the magnetic susceptibilities of the salts, the relation of the susceptibility to the absolute temperature having been determined for each salt in earlier experiments. The γ -ray heatings gave the specific heat in arbitrary units. The absolute values of the specific heats were found by extrapolating the results of paramagnetic relaxation measurements at higher temperatures. The measured specific heat of neodymium magnesium nitrate is compared with the value calculated from paramagnetic resonance data, and good agreement is found.

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