What is the enthalpy of formation of $NH_3$ if the bond enthalpies are $(N \equiv N) = 941 \ kJ/mol$,$(H-H) = 436 \ kJ/mol$,and $(N-H) = 389 \ kJ/mol$?

The heats of solution of anhydrous $CuSO_4$ and $CuSO_4 \cdot 5H_2O$ are $-15.89 \, kcal \, mol^{-1}$ and $2.80 \, kcal \, mol^{-1}$ respectively. What is the heat of hydration of anhydrous $CuSO_4$ in $kcal \, mol^{-1}$?

The $H_2O_{(g)}$ molecule dissociates as:
$(i)$ $H_2O_{(g)} \to H_{(g)} + OH_{(g)}; \Delta H = 490 \ kJ$
$(ii)$ $OH_{(g)} \to H_{(g)} + O_{(g)}; \Delta H = 424 \ kJ$
The average bond energy (in $kJ$) for water is

With the help of the following data,find out the change in heat content for the reaction:
$C_2H_{4(g)} + H_{2(g)} \to C_2H_{6(g)}$

Bond	Bond energy $(kJ \ mol^{-1})$
$C-H$	$413$
$C-C$	$348$
$C=C$	$610$
$H-H$	$436$

The enthalpies of combustion of cyclohexane $(C_6H_{12})$,cyclohexene $(C_6H_{10})$,and $H_2$ are $-3920, -3800$,and $-241 \, kJ \, mol^{-1}$ respectively. The heat of hydrogenation of cyclohexene is ...... $kJ \, mol^{-1}$.

The heat of combustion of carbon to $CO_2$ is $-393.5 \ kJ/mol$. The heat released upon formation of $35.2 \ g$ of $CO_2$ from carbon and oxygen gas is $..... \ kJ$.