A. Hackert et V. Plies, DETERMINATION OF TEMPERATURE-DEPENDENT PA RTIAL PRESSURES IN CLOSED SYSTEMS - A NEW METHOD - THE HEAT OF FORMATION FOR PTI2(S), Zeitschrift fur anorganische und allgemeine Chemie, 624(1), 1998, pp. 74-80
Citations number
29
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Zeitschrift fur anorganische und allgemeine Chemie
A new method to determine temperature dependent partial pressures of g
aseous species in equilibria with condensed phases in closed systems (
silica ampoules) at temperatures up to 1000 degrees C and pressures p(
i) 0.01 <p(i) < 10 bar is presented. It is based on the determination
of the change of mass in the gasphase caused by solid-gas transition a
t higher temperatures of substances which are deposited at one end of
the ampoule. The results of the measurements give informations about r
eaction mechanisms, enthalpies and entropies. The reliability of the m
ethod is demonstrated at the example of the system Pt/I-2. The heat of
formation and the entropy of PtI2(s) (Delta(B)H degrees(PtI2(s),298)
=-51.4kJ mol-l, S degrees(PtI2(s), 298) = 119.3 J . K-1. mol(-1)) are
computed from experimental results. The heat of thermal decomposition
of PtI2(s) was reconsidered by Knudsen Mass Spectrometry.