Harold M. Feder

Thermodynamic properties and ordering in liquid NaK alloys

Abstract The thermodynamic activities of sodium and potassium were determined by vapour-phase absorption spectrophotometry of atomic resonance lines. Both components exhibit significant positive deviations from ideality. Excess Gibbs energies computed from the activity data were combined with available heat-of-mixing data to yield values for excess entropies. The entropy of mixing which was found to be ideal in the sodium-rich liquid alloys provides no support for the earlier speculations about the existence of Na2K molecules therein. The partial molar excess entropy of sodium in dilute solution in potassium was found to be surprisingly large and negative for a system of this type. A plausible model, involving sodium-sodium pairing, is proposed to account for the loss of configurational entropy.

SOLUBILITY OF HELIUM AND ARGON IN LIQUID SODIUM.

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Fluorine bomb calorimetry

Techniques which were developed for fluorine bomb calorimetry are described. Construction materials, safety measures, manipulation of samples, and calorimeter calibration are discussed. Tests carried out on 25 metals and metalloids and on 15 inorganic compounds indicated that reactions of 75% of these substances with fluorine could be studied calorimetrically. It is concluded that fluorine calorimetry can be carried out without undue hazard and is