A municipal solid waste $($MSW$)$ sample has the following molecular composition: C$970$H$2667\mathrm{.}5$O$1097\mathrm{.}6$N$15\mathrm{.}25$ a$)$ Estimate the energy content $($in kJ$/$kg$)$ of the MSW sample using the modified Dulong formula given as: Energy Content $($kJ$/$kg$)=337\mathrm{.}27.$C $+1418\mathrm{.}86.($H$,+93\mathrm{.}04.$S$+23\mathrm{.}26.$ N $8[$Atomic Weights: C $=12,$ H $=1$; O $=16,$ S $=32,$ N $=14]$ b$)$ Explain why the oxygen content is divided by $8$ and subtracted from the hydrogen content