Part of the stability of the C=O bonds in CO2
arises from resonance stabilization involving bond structures
of the type
Had there been no resonance or delocalization in CO2,
the C=O bonds would have strengths of 174 kcal mole-1,
as they do in other non-delocalized molecules, rather than the
192 kcal mole-1
that is observed in CO2.
Without delocalization, the calculation in Part E would have
been
We now
can summarize the three components in the molar heat of combustion
of methane:
