| Popis: |
The standard molar reaction enthalpies of two reactions, CeCl3 · 7H2O(s) + 3CCl3COOH(s) = Ce(TCA)3· 3H2O(s) +3HCl(g) + 4H2O(1) (1) and Ce(TCA)3· 3H2O (s) + 2C9H7NO (S) = Ce(TCA) (C9H6NO)2 (s) + 2CCl3COOH(s) + 3H2O(1) (2), were investigated by classical solution calorimetry and an isoperibol calorimeter at 298.15 K. The standard molar enthalpies ΔsH·m of solution of CeCl3 · 7H2O(s), 3CCl3COOH(s), Ce(TCA)3 · 3H2O(s), Ce(TCA)3 · 3H2O(s), 2C9H7NO(s), Ce-(TCA) (C9H6NO)2(s) and 2CCl3COOH(s) were determined to be (50.615 ± 0.028), (23.431 ± 0.027), (94.206 ± 0.010), (54.151 ± 0.020), (27.485 ± 0.045), (106.392 ± 0.060) and-(14.893 ± 0.026) kJ/mol, respectively. The reaction enthalpies ΔrH⊖m of reactions (1) and (2) were obtained to be (204.279 ± 0.023) and-(9.863 ± 0.041) kJ/mol, respectively. According to the above results and the data given in literature, through Hess' law, the standard molar enthalpies ΔtH⊖m of formation of Ce(TCA)3 ± 3H2O(s) and Ce(TCA)(C9H6NO)2 (s) were estimated to be-(3060.0 ± 0.087) and-(1369.0 ± 0.292) kJ/mol, respectively. |
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