Enthalpies of formation calculated

Table 3 contains the enthalpies, zero point energies, entropies and free enthalpies of the activation and reaction steps (3)—(5). The enthalpies are the pure differences of the enthalpies of formation calculated by MINDO/3 at T = 298 K in the gas phase. The free enthalpies were calculated with the help of enthalpies corrected by the zero point energies and of the entropies given in Table 3. 

Table 25. An additional correction of APV = RTAn = 0.6 kcal mol-1 is made for die reaction itself. Connectivity is to the leftmost atom in Y. Calculated from the enthalpies of formation tabulated in References 13 and 224. cFrom Reference 234. From Reference 21. eNot calculated. f From enthalpy of formation calculated in Reference 229. Enthalpy of formation of C2H3 from References 226 and 227. Calculated value from Reference 228. 1 Calculated value from Reference 92. Calculated enthalpy of formation from Reference 219. Calculated value from Reference 233. ...

The program comprises a large data base with over 1100 substances with enthalpies of formation Calculations are performed only for standard conditions (25°C,1 bar)... 

Equation 2.26 is also used to evaluate the uncertainty of a standard enthalpy of formation, calculated from a reaction enthalpy. Consider, for instance, a selected value for the standard enthalpy of combustion of ferrocene, A CH° [Fe(r 5-C5H5)2, cr] = —5891.5 4.2 kJ mol-1 [31],... 

In the absence of experimental results, predicted A/// values are indicated in parentheses. Two A results fisted in the column reporting experimental values are indicated in parentheses these are theoretical results offered for comparison, deduced from enthalpies of formation calculated by Dewar and de Llano [269]. 

All the experimental enthalpies of the Grignard reaction appear in Table 5 along with the enthalpies of formation calculated using the same method as illustrated above. Unfortunately there are no liquid enthalpy of formation data for the halogenated ketones, nor are... 

All group contributions and structural corrections are based on experimental data of Rossini et al. (1953), the free enthalpies of formation calculated agree with the literature values within 3 kj. For non-hydrocarbons the accuracy is less good and deviations up to 12 kj may occur. 

Based on the amount of mass flow of products and the enthalpy of formation calculated, the overall output enthalpy is obtained, which is —808.6 kJ kg . Under the conditions of 101-203 MPa, 200-300 C, the overall output enthalpy can be obtained as —2124.7 kJ kg according to Equation (28.9) ... 

Second law values of the enthalpy of formation calculated as discussed in Appendix A from the electrochemical measurements in [60FIN/WAG], [66SAD/SEM], and [73SHA/MIS] are tabulated in Table V-39 together with the results of direct synthesis calorimetry investigations made by Hajiev [70HAJ] and Boone and Kleppa [92BOO/KLE]. 

From the standard enthalpies of formation, calculate A/ n for the reaction... 

The inconsistency of the cited enthalpies of sublimation of naphthacene is a problem. Of five citations since 1951 including the newest, three are ca. 125 kJ moP. A 1952 determination is 8 kJ moP less and a 1980 determination is 18 kJ moP higher. There is only one solid enthalpy of formation. Ref. 4 recommends an average (291.4 9.4 kJ moP ) of the two gaseous enthalpies of formation calculated using the highest enthalpy of sublimation as well as the median value. 

Both second and third law values of the enthalpy of reaction were determined using two different detection techniques, electrometer analogue and ion counting for Reaction (V.57) whereas only the former was used for Reaction (V.58). For Reaction (V.57), the third law reaction data were significantly more consistent than the second law values and, as such, were selected by [78KLE/CUB]. The values selected for the enthalpy of reaction were (136.4 4.6) and (332.6 4.6) kJ-moP for Reactions (V.57) and (V.58), respectively. The enthalpy of formation calculated from the two reactions, utilising the enthalpy of formation of Zrl4(g) and the selected auxiliary enthalpy of... 

Scheme 3.1 Example of enthalpy of formation calculation with isodesmic reactions having bonds and groups conservation.

Table 1 lists the experimental values of the enthalpies of reactions (5), (2), and (3), which take account of the experimental errors and the reproducibility of the measurements. These values of AHg, AHj, and AH3 were used to calculate the enthalpies of formation of the rare-earth mono- and sesquisulfides in accordance with Eqs. (8) and (9). The results are given in Table 2. This table includes also the experimental values of the enthalpies of formation calculated per 1 g-atom of sulfur. The published values included in this table were taken from original papers or from textbooks [21], where these values were reviewed critically.

Many portable gas heaters and grills use propane, C3Hg(g), as a fuel. Using standard enthalpies of formation, calculate the quantity of heat produced when 10.0 g of propane is com-... 

Enthalpies of formation were derived from enthalpies of reaction measured for reactions of NF3 with various partners in bomb calorimeters and enthalpies of formation of the various reactants from the literature. The following table lists the studied reactions along with the enthalpies of reaction and enthalpies of formation calculated from each reaction. 

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