The bond dissociation energy of molecules is.......

The enthalpy of formation of ammonia is $-46.0 \ kJ \ mol^{-1}$. The enthalpy change for the reaction $2NH_{3(g)} \rightarrow N_{2(g)} + 3H_{2(g)}$ is ............... $kJ \ mol^{-1}$.

Which of the following equations correctly represents the standard heat of formation $(\Delta H_f^o)$ of methane?

Carbon and carbon monoxide burn in oxygen to form carbon dioxide according to the following reactions:
$C(s) + O_2(g) \to CO_2(g)$; $\Delta H = -394 \ kJ \ mol^{-1}$
$2CO(g) + O_2(g) \to 2CO_2(g)$; $\Delta H = -569 \ kJ \ mol^{-1}$
The heat of formation of $1 \ mol$ of carbon monoxide is thus ..... $kJ \ mol^{-1}$.

The heat of combustion of $C_xH_y$,carbon,and hydrogen are $a, b$,and $c \ cal/mole$ respectively. The heat of formation of $C_xH_y$ will be:

Based on Hess's law calculations,what is the average bond energy of $S-O$ in $SO_3$ if $\Delta H_f^o$ of $SO_3$ is $-270 \ kJ \ mol^{-1}$. The bond energy of $O=O$ is $495 \ kJ \ mol^{-1}$ and the heat of sublimation for $S_{(s)}$ is $277 \ kJ \ mol^{-1}$? (Given: Bond energy of $S=O$ is not provided,assume the reaction $S_{(s)} + \frac{3}{2} O_2(g) \rightarrow SO_3(g)$). Note: The provided values in the prompt were inconsistent with standard chemical data; using standard values: $\Delta H_{sub}(S) = 277 \ kJ \ mol^{-1}$,$BE(O=O) = 495 \ kJ \ mol^{-1}$,$BE(S-O) = 330 \ kJ \ mol^{-1}$ is not the goal,we calculate based on the provided logic.