Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6660842 | The Journal of Chemical Thermodynamics | 2014 | 5 Pages |
Abstract
Two mixed alkali-alkaline earth metal borates of NaSrBO3 and KSr4B3O9 have been synthesized by high-temperature solid state reaction, which were further characterized by XRD, FT-IR, DTA-TG techniques and chemical analysis. The molar enthalpies of solution of NaSrBO3(s) and KSr4B3O9(s) in 2.00 cm3 of 1 mol · dmâ3 HCl(aq), at T = 298.15 K were measured to be â(206.84 ± 0.43) kJ · molâ1 and â(494.59 ± 0.53) kJ · molâ1, respectively. The molar enthalpy of solution of NaCl(s) in 2.00 cm3 of {1 mol · dmâ3 HCl + H3BO3 + Sr(OH)2 · 8H2O}(aq) mixed solvent at T = 298.15 K was measured to be (5.17 ± 0.02) kJ · molâ1. From these data and with the incorporation of the previously determined enthalpies of solution of H3BO3(s) in HCl(aq) of Sr(OH)2 · 8H2O(s) in (HCl + H3BO3)(aq), and of KCl(s) in {HCl + H3BO3 + Sr(OH)2 · 8H2O}(aq), together with the use of the molar enthalpies of formation for NaCl(s)/KCl(s), Sr(OH)2 · 8H2O(s), H3BO3(s), HCl(aq) and H2O(l), the standard molar enthalpies of formation of NaSrBO3(s) and KSr4B3O9 were calculated to be â(1653.1 ± 1.4) kJ · molâ1 and â(5071.1 ± 3.4) kJ · molâ1 on the basis of the designed thermochemical cycles, respectively.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Jun-Feng Wang, Xiao-Lan Wang,