Partial Saturated Vapor Pressure of Sodium Nitrite Over the System NaNO2-KNO3

The partial pressure of sodium nitrite in the system NaNO₂-KNO₃ was measured at 798, 823, and 848 K. The dependence of the logarithm of the NaNO₂ pressure on inverse temperature is presented. Coefficients A and B of the Clausius-Clapeyron equation and the partial molar heats of vaporization are calculated. The activity and activity coefficient of sodium nitrite are determined. The dependences of ac- tivity and activity coefficient of sodium nitrite and potassium nitrate are presented as functions of composition of the NaNO₂-KNO₃ system. The consistency of the activity coefficients is verified using the Redlich-Kister integral.     

Theory of the implementation of the fundamental parameter method for the X-ray fluorescence determination of low-atomic-number elements

The theory of X-ray fluorescence generation in elements with a low atomic number Z is extended to the case of host matrices with high Z. The total contribution of the selective excitation effects is estimated with regard to the cascade K-L transitions. The influence of the elemental composition of the matrix and the excitation conditions on the X-ray fluorescence intensity of the elements in study is assessed. The accuracy of the model of X-ray fluorescence generation in the low-atomic-number elements is confirmed by the agreement of the experimental and calculated intensities of carbon in various carbon-containing compounds.     

Gibbs Energy and Entropy of Mixing in the NaNO2-KNO3 System

The activity and activity coefficients of the components of the NaNO₂-KNO₃ system, determined from the experimental data on the saturated vapor pressure at 798, 823, and 848 K, are used to calculate the relative and excess partial molar Gibbs energies (G _i and G _i ^{e x c}), entropies (S _i and S _i ^{e x c}), and integral relative and excess thermodynamic functions (G, G ^{e x c}, S, and S ^{e x c}) of the system.     

The Formation of Analytical and Background Signals in Radioisotope X-ray Fluorescence Analysis Using a 241Am Radioactive Source and a Si(Li) Detector

Reasons for the appearance of a background signal in the relatively soft x-ray range (2–15 keV) upon fluorescence excitation with the ²⁴¹Am radioisotope are discussed. Mathematical models are proposed for the interaction of the radiation of the radioactive source with the sample and the Si(Li) detector, capable of describing the appearance of the analytical and background signals. It was shown that processes occurring in the Si(Li) detector should be taken into account to explain and calculate the background signal in this range. The results of calculations agree well with the experimental data obtained using an ²⁴¹Am radiation source for fluorescence excitation.     

Saturated Vapor Pressure over the Melts of the NaNO2-NaNO3 System

The partial pressures of sodium nitrite and sodium nitrate over the system NaNO₂-NaNO₃ were determined at 798, 823, and 848°C. For sodium nitrate, A and B coefficients of the Clausius-Clapeyron equation, partial molar heats of vaporization, activities, and activity coefficients were calculated as functions of composition.     

Solid polymeric electrolyte based on poly(ethylene carbonate)-lithium perchlorate system

Interaction in the poly(ethylene carbonate)-lithium perchlorate system was studied by means of IR spectroscopy and differential-thermal and X-ray structural analyses. The electrical conductivity of the composites obtained was measured.     

Lithium-Conducting Polymer Electrolytes for Chemical Power Sources

Polymer electrolytes for lithium and lithium-ion chemical power sources are described.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 1, 2005, pp. 3–20.Original Russian Text Copyright © 2005 by Kolosnitsyn, Dukhanin, Dumler, Novakov.     

Mass-spectrometric examination of vaporization of sodium nitrite and sodium and potassium nitrates

Vaporization of sodium nitrite and sodium and potassium nitrates was examined by high-temperature mass spectrometry. The inverse temperature dependences of the vapor pressure logarithm for these compounds were presented. Enthalpies of vaporization and standard enthalpies of formation of gaseous NaNO₂, NaNO₃, and KNO₃ were determined.     

Saturated Vapor Pressure Over Melts of the Binary System NaNO2-KNO3

The partial pressures of sodium nitrite and potassium nitrate over melts of the binary system NaNO₂-KNO₃ were measured at 798, 823, and 848 K. Negative deviations of the vapor pressure from Raoult's law, which decrease with increasing temperature, are established. Coefficients A and B of the Clausius-Clapeyron equation, partial molar heats of vaporization, activity and activity coefficient are calculated as functions of composition for potassium nitrate.     

Thermodynamic characteristics of the system NaNO<Subscript>2</Subscript>-NaNO<Subscript>3</Subscript>

The activities and activity coefficients of the components of the system NaNO₂-NaNO₃, obtained from experimental saturated vapor pressures measured at 798, 823, and 848 K, were used to calculate the total and excess partial molar Gibbs energies , , entropies , , and total relative and excess thermodynamic properties G, G ^ex, S, S ^ex of the system.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1747–1749.Original Russian Text Copyright © 2004 by Glazov, Dukhanin, Dkhaibe, Losev.