Single bond, energies energy values

Calculated values are derived from data at 298 K. The experimental values are DJ figures. F indicates use of the fully weakened covalent single bond energy, F " the unweakened bond energy. 

Values for single-bond energies, defined in this way, for many bonds can be found by this process—for the S—S bond from the Sg molecule (an eight-membered ring containing eight S—S bonds), for N—H, P—H, S—H, and so forth from NH, PHS, H S, and so forth. These values are given m Table 3-4. 

Figl 3-6.—The values of single-bond energies of elements. 

The standard enthalpy of formation for N2H4(g) Is 95.4 kJ/mol. Use this and the data In Exercise 76 to estimate the N—N single bond energy. Compare this with the value In Table 8.4. 

In the table of bond energies separate values are conveniently listed for singly, doubly, or triply bound atoms, for O in C==0, for 0 in C—0—C, and so on. 

The cleavage of the P-C bond in some aminophosphonates is an unusual reaction, because the strength of a single P-C bond is comparable with the strength of a single C-C bond (the energy value for the P-C bond is about 63 kcal/mol). 

The standard enthalpy of formation of H202(g) is -136 kj mol . Use this value, with other appropriate data from the text, to estimate the oxygen-to-oxygen single-bond energy. Compare your result with the value listed in Table 10.3. 

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