Vaporization studies on sodium oxide
| Autor: | Dietmar Kobertz |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Sodium oxide General Chemical Engineering Sodium Enthalpy 0211 other engineering and technologies Thermodynamics chemistry.chemical_element 02 engineering and technology General Chemistry Partial pressure Mass spectrometry 01 natural sciences Computer Science Applications Gibbs free energy symbols.namesake chemistry.chemical_compound chemistry 0103 physical sciences Vaporization symbols Equilibrium constant 021102 mining & metallurgy |
| Zdroj: | Calphad. 64:327-333 |
| ISSN: | 0364-5916 |
| DOI: | 10.1016/j.calphad.2019.01.006 |
| Popis: | The vaporization of pure Na2O(c) was investigated at temperatures of 900–1165 K with the method of Knudsen Effusion Mass Spectrometry (KEMS). Thermodynamic quantities of sublimation enthalpy, entropy and Gibbs energy were derived from the partial pressures of gaseous species Na and O2 over the pure sodium oxide reference samples. The sublimation enthalpies obtained for the reaction “Na2O = 2 Na(g) + ½ O2(g)” are for Na: ∆sub H 1000 0 = 243 ± 4, 2nd Law, and 241 ± 3, 3rd law. For O2: ∆sub H 1000 0 = 242 ± 2, 2nd Law, and 241 ± 2, 3rd law kJ mol−1. The Gibbs energy ∆sub G 1000 0 and entropy ∆sub S 1000 0 for sublimation were determined as 133 ± 5 kJ mol−1 and 110 ± 2 J mol−1 K−1 for sodium, and for O2: ∆sub G 1000 0 =143 ± 4 kJ mol−1 and entropy ∆sub S 1000 0 = 100 ± 2 J mol−1 K−1. From the equilibrium constant for the reaction Na2O(c) = 2Na(g) + ½ O2(g) the enthalpy ∆r H 1000 0 resulted in 605 ± 6, 2nd law, and 611 ± 9 kJ mol−1, 3rd law. The Gibbs energy ∆r G 1000 0 and entropy ∆r S 1000 0 were deduced as 342 ± 9 kJ mol−1 and 269 ± 5 J mol−1 K−1. |
| Databáze: | OpenAIRE |
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