Thermodynamics of sodium molybdate evaporation

High-temperature mass-spectrometry is used to study the evaporation of Na 2 MoO 4(l) at 1050–1300 K. Na 2 MoO 4(g) molecules are found to be present in the vapor. The partial pressure of Na 2 MoO 4(g) is determined to be log p = 13794/ T + 6.19. The enthalpy of sublimation Δ s H 0 ∘ (Na 2 MoO 4 (s) ) = 352 ± 20 kJ/mol is determined using the third law of thermodynamics. The atomization energy of the Na 2 MoO 4(g) molecules is calculated to be Δ at H 0 ∘ (Na 2 MoO 4(g) ) = 2960 ± 40 kJ/mol.