The heat of combustion of a substance is:

The standard enthalpy of formation $(\Delta_f H^o_{298})$ for methane,$CH_4$ is $-74.9 \ kJ \ mol^{-1}$. In order to calculate the average energy given out in the formation of a $C-H$ bond from this,it is necessary to know which one of the following?

If $C_{(s)} + O_{2(g)} \longrightarrow CO_{2(g)}; \Delta H = r$ and $CO_{(g)} + \frac{1}{2} O_{2(g)} \longrightarrow CO_{2(g)}; \Delta H = s$,then the heat of formation of $CO$ is

The value of heat generated when $36.5 \, g$ of $HCl$ and $40 \, g$ of $NaOH$ react during neutralization is.....$kcal$.

For the reaction,$2 H_{2(g)} + O_{2(g)} \longrightarrow 2 H_2 O_{(g)}$,$\Delta H^{\circ} = -573.2 \ kJ$. What is the heat of decomposition of water per mol (in $kJ$)?

The bond energies of $H-H$ and $Cl-Cl$ are $430 \ kJ \ mol^{-1}$ and $240 \ kJ \ mol^{-1}$ respectively. If the $\Delta H_f$ (enthalpy of formation) of $HCl$ is $-90 \ kJ \ mol^{-1}$,what is the $H-Cl$ bond energy in $kJ \ mol^{-1}$?