1,721,015 research outputs found
Proprietà chimico-fisiche di soluzioni estremamente diluite
No full textLo studio chimico-fisico riguardante le soluzioni estremamente diluite è stato svolto con l'intento di evidenziare un'ipotetica variazione strutturale che il solvente acqua subisce in seguito alla procedura di preparazione che prevede l'iterazione di due processi: la diluizioni e la dinamizzazion
Proprietà termodinamiche di soluzioni ad alta diluizione
No full textIl lavoro dimostra,utilizzando tecniche consolidate, che le proprietà chimico fisiche di soluzioni estremamente diluite risultano permanentemente variate a seguito della procedura di preparazione
Fenomeni e processi idroisteretici indotti da trattamenti meccanici nelle soluzioni estremamente diluite
No full textE' stato studiato il comportamento delle estreme diluizioni con tecniche chimico-fisiche quali misure conduttometriche, misure calorimetriche, misure potenziometriche (pH, forza elettromotrice).Tali studi hanno dimostrato la mutata struttura sovramolecolare del solvente acqua a seguito del protocollo di preparazione consistente in successive diluizioni e dinamizzazioni
NEW PHYSICO-CHEMICAL PROPERTIES OF EXTREMELY DILUTED AQUEOUS SOLUTIONS
No full textThe “extremely diluted solutions” are anomalous solutions obtained through the iteration of two processes: a dilution 1:100 in mass and a succussion. The iteration is repeated until extreme dilutions are reached (less than 1.10-5 mol kg-1) to the point that we may call the resulting solution an “extremely diluted solution”, namely the composition of the solution is identical to that of the solvent used (e.g. twice distilled water). We conducted thermodynamic and transport measurements of the solutions and of the interaction of those solutions with acids or bases. The purpose of this study is to obtain information about the influence of successive dilutions and succussions on the water structure of the solutions under study. We measured the heats of mixing of acid or basic solutions with such “extremely diluted solutions”, their electrical conductivity and pH, comparing with the analogous heats of mixing, electrical conductivity and pH of the solvent. We found some relevant exothermic excess heats of mixing, higher electrical conductivity and pH than those of the untreated solvent. The measurements show a good correlation between independent physico-chemical parameters. Care was taken to take into account the effect of chemical impurities deriving from the glass containers. Here we thus show that successive dilutions and succussions can permanently alter the physico-chemical properties of the water solvent. The nature of the phenomena here described still remains unexplained, nevertheless some significant experimental results were obtained
Hydrophilic interactions determine cooperativity of hydrophobic interactions and molecular recognition in aqueous solutions of non electrolytes. The preferential configuration model
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A molecular model of interaction between extremely diluted solutions and NaOH solutions used as titrant. Conductometric and pHmetric titrations.
No full textThe "memory of water" :an almost deciphered enigma. Dissipative structures in the extremaly diluted aqueous solutions of the homeopathic medicine
No full textIn the last decade, we have investigated from the physicochemical point of view, whether water prepared by the procedures of homeopathic medicine (leading inexorably to systems without any molecule different from the solvent) results in water different from the initial water? The answer, unexpectedly, but strongly supported by many experimental results is positive. We used well-established physicochemical techniques: flux calorimetry, conductometry, pHmetry and galvanic cell electrodes potential. Unexpectedly the physicochemical parameters evolve in time. The water solvent exhibits large changes in measurable physicochemical properties as a function of its history, the solute previously dissolved, and time. In particular we found evidence of two new phenomena, both totally unpredicted, in homeopathic dilutions: the presence of a maximum in the measured physicochemical parameters vs sample age, and their dependence on the volume in which the dilution is stored. These new experimental results strongly suggest the presence of an extended and 'ordered' dynamics involving liquid water molecules
Role of functional-group position in determining the interaction between structure-making and structure-breaking solutes. A microcalorimetric study of the interactions in aqueous solutions between positional isomers of alkan-m-ols and urea or biuret
No full textEnthalpies of dilution of ternary aqueous solutions containing biuret or urea and positional isomers of alkan-m-ols have been determined by flow microcalorimetry at 298.15 K. Pairwise cross-interaction coefficients of the virial expansion of the excess enthalpies were evaluated. The values of the coefficients are positive, depending in a very complex manner on the length of the alkyl chain and on the position occupied by the hydroxy group along the alkyl chain. The behaviour of these systems seems to be determined by a balance between favourable hydrophilic-hydrophilic and repulsive hydrophilic-hydrophobic interactions. When the hydroxy group occupies more central positions, unfavourable interactions prevail and the cross coefficient for the alkanol bearing the longest alkyl chain is almost zero
Hydrophilic interactions determine cooperativity of hydrophobic interactions and molecular recognition in aqueous solutions of non electrolytes. The preferential configuration model
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