概念不清.第一个ΔH°f[O(g)]和O=O的bound energy是什么关系,要除以2么

概念不清.第一个ΔH°f[O(g)]和O=O的bound energy是什么关系,要除以2么
Which of the following statements are FALSE,given the following bond dissociation energies?Assume that bond energies accurately determine heats of reaction.Several choices possible.
BE[H-H] = 436.4 kJ/mol
BE[H-N] = 393 kJ/mol
BE[H-O] = 460 kJ/mol
BE[O=O] = 498.7 kJ/mol
ΔH°f[O(g)] = 498.7 kJ/mol
An H-H bond is stronger than an H-N bond.
ΔH°f[H2O(g)] = -234 kJ/mol
ΔH°[NH3(g) ---> N(g) + 3 H(g)] = 1179 kJ/mol
NH3(g) + HO(g) ---> NH2(g) + H2O(g) is an endothermic reaction.