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.42 From the values obtained for the standard enthalpies of the reaction ( 5 ) and by using appropriate thermochemical cycles [ 27 ], the following thermochemical parameters for the adducts were determined: the standard enthalpies of formation (Δ f H θ

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increases ( Fig. 7 ). The uncertainties on these values can not been determined because the literature values are given without any error. Table 9 Standard enthalpies of formation at 298 K calculated according

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Abstract  

The copper(II) complex of 6-benzylaminopurine (6-BAP) has been prepared with dihydrated cupric chloride and 6-benzylaminopurine. Infrared spectrum and thermal stabilities of the solid complex have been discussed. The constant-volume combustion energy, Δc U, has been determined as −12566.92±6.44 kJ mol−1 by a precise rotating-bomb calorimeter at 298.15 K. From the results and other auxiliary quantities, the standard molar enthalpy of combustion, Δc H m θ, and the standard molar of formation of the complex, Δf H m θ, were calculated as −12558.24±6.44 and −842.50±6.47 kJ mol−1, respectively.

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Abstract  

The combustion energy of thioproline was determined by the precision rotating-bomb calorimeter at 298.15 K to be Δc U= –2469.301.44 kJ mol–1. From the results and other auxiliary quantities, the standard molar enthalpy of combustion and the standard molar enthalpy of formation of thioproline were calculated to be Δc H m θC4H7NO2S, (s), 298.15 K= –2469.921.44 kJ mol–1 and Δf H m θC4H7NO2S, (s), 298.15K= –401.331.54 kJ mol–1.

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Abstract  

The standard molar enthalpy of formation Δf H m 0=–760±12 kJ for amorphous silicon nitride a-Si3N4 has been determined from fluorine combustion calorimetry measurements of the massic energy of the reaction: a-Si3N4(s)+6F2(g)=3SiF4(g)+2N2(g). This value combined with Δf H m 0= –828.9±3.4 kJ for a-Si3N4 indicates that determined for the first time molar enthalpy change for the transition from amorphous to α-crystalline form Δtrs H m 0=69±13 kJ is very evident, in spite of its large uncertainty range resulting from impurity corrections.

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Abstract  

By using a DSK of the French firm Seteram, the standard enthalpies of formation of 5 tellurites and 5 tetratellurites of the rare earths Gd, Tb, Dy, Tm and Yb were determined for the first time. Three parallel determinations for each sample were compared. The results are very similar, which is an indication of the great reliability of the method used and the correctness of the data obtained.

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Abstract  

The enthalpies of solution in water of RE(His)(NO3)3 H2O (RE=La—Nd, Sm—Lu, Y) were measured calorimetrically at 298.15 K, and the standard enthalpies of formation of RE(His)aq 3+ (RE=La—Nd, Sm—Lu, Y) were calculated. The plot of the enthalpies of solution vs. the atomic numbers of the elements in the lanthanide series exhibits the tetrad effect.

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Abstract  

The enthalpies of solution in water of L--methionine and its zinc complexes Zn(Met)Cl2, Zn(Met)2Cl2·2H2O, Zn(Met)(NO3)2·1/2H2O, Zn(Met)3(NO3)2·H2O and Zn(Met)SO4·H2O have been measured at 298.15 K. The standard enthalpy of formation of met(aq) has been calculated. The experimental results have been discussed.

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Thermochemical and thermodynamical properties of HTSC phases are reviewed for the Y-Ba-Cu-O system and also presented for the newly calculated Bi-Sr-Cu-O system stressing out stoichiometric and phenomenological viewpoints. Simulated data are listed for (H 298 o-H o o, phase transformation temperatures, standard entropies, standard enthalpies of formation, heat capacities in crystalline phase, etc. Pseudobinary phase diagrams are treated showing the effect of oxygen partial pressure particularly illustrated on the (Sr, Bi, Ba)-Cu-O system.

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