Given that $C_{(g)} + 4H_{(g)} \longrightarrow CH_{4(g)}$,$\Delta H^{\circ} = -1665 \ kJ$. What is the bond energy per mole of $C-H$ bond?

Calculate the heat of formation of ethyl alcohol in $kcal/mol$ from the following data:
$C_{(s)} + O_{2(g)} \to CO_{2(g)}, \Delta H = -94 \ kcal$
$H_{2(g)} + \frac{1}{2} O_{2(g)} \to H_2O_{(l)}, \Delta H = -68 \ kcal$
$C_2H_5OH_{(l)} + 3O_{2(g)} \to 2CO_{2(g)} + 3H_2O_{(l)}, \Delta H = -327 \ kcal$

If enthalpies of formation of $C_2H_{4(g)}$,$CO_{2(g)}$ and $H_2O_{(l)}$ at $25 \ ^\circ C$ and $1 \ atm$ pressure are $52$,$-394$ and $-286 \ kJ \ mol^{-1}$ respectively,the enthalpy of combustion of $C_2H_{4(g)}$ will be.....$kJ \ mol^{-1}$.

The bond energy is the energy required to

The bond enthalpies of heavy hydrogen $(D-D)$,oxygen $(O=O)$,and heavy water $(D-O)$ are $+400$,$+498$,and $+490 \ kJ \ mol^{-1}$,respectively. The $\Delta_{r} H^{\circ}$ of the reaction to produce $D_2O$ is: