Estudo experimental e modelagem do volume em excesso para sistemas do tipo agua/acetonitrila/eletrolito a pressão ambiente na faixa 283,15-308,15K

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

In this work the behavior of the excess volume of systems of the type water-acetonitrile-electrolyte as a function of the composition (fraction molar of the solvent between O and 1, fraction molar of the salt from 0,001 to 0,003) and of the temperature (283,15K - 308,15K) at room pressure, using the a vibrating-tube densimeter was studied. The system water-acetonitrile was chosen by because the components are highly polar, miscible at room temperature and of different chemical nature. The salts lithium chloride, sodium cWoride and potassium chloride were chosen because they interact preferably with one of the solvents and for the cation influence and anion of the same periodic group. For all the studied saline systems the excess volume becomes more negative when compared to the system water-acetonitrile, and the largest effects happen for larger concentrations of salto The effect of the temperature in the excess volume, is such that a temperature increase turns the excess volume in less negative. The experimental data were correlated by the ERAS model, for the system without salt and by the ERAS model modified (with a term due to Hepler), for the systems with salt. It was verified that the used model was not capable to correlate the experimental data for the studied systems. A linear correlation between the excess volume was established at the minimum point in function of the radius of the cation

ASSUNTO(S)

termodinamica solução (quimica) agua acetonitrila

ACESSO AO ARTIGO

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