THE SURFACE ENERGIES OF CALCIUM OXIDE AND CALCIUM HYDROXIDE
Autor: | D. L. Kantro, C. H. Weise, Stephen Brunauer |
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Rok vydání: | 1956 |
Předmět: | |
Zdroj: | Canadian Journal of Chemistry. 34:729-742 |
ISSN: | 1480-3291 0008-4042 |
DOI: | 10.1139/v56-096 |
Popis: | The total surface energies (or surface enthalpies) of calcium oxide and calcium hydroxide were determined by measuring the heats of solution in 2 N nitric acid of calcium oxide and calcium hydroxide having high and low specific surface areas, and by determining the surface areas by the B.E.T. method, using nitrogen as adsorbate. The molecular area of nitrogen was taken to be 16.2 Å2 at 77.3 °K. Precision determinations of the lattice parameters indicated that the high and low surface substances had the same unit cell dimensions, and X-ray line broadening measurements indicated that the crystals were perfect or nearly perfect. The surface energy of calcium oxide at 23 °C. was found to be 1310 ± 200 erg/cm.2, which compares well with the theoretical value of 1100 erg/cm.2 The surface energy of calcium hydroxide at 23 °C. was found to be 1180 ± 100 erg/cm.2 The heat of the reaction CaO (c, 23°) + H2O (l, 23°) = Ca(OH)2 (c, 23°), for crystals having negligible specific surface areas, was found to be −15,620 cal. |
Databáze: | OpenAIRE |
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