Given that bond energies of $H-H$ and $Cl-Cl$ are $430 \ kJ \ mol^{-1}$ and $240 \ kJ \ mol^{-1}$ respectively and $\Delta H_f$ for $HCl$ is $-90 \ kJ \ mol^{-1},$ the bond enthalpy of $HCl$ is ............... $kJ \ mol^{-1}$.

The combustion enthalpies of carbon,hydrogen,and methane are $-393.5 \ kJ/mole$,$-284.8 \ kJ/mole$,and $-890.4 \ kJ/mole$ respectively at $25 \ ^oC$. The value of the standard formation enthalpy of methane at that temperature is ..... $kJ/mole$.

$PbO$ exists in two crystalline forms: yellow and red. The standard enthalpies of formation for these two forms are $-217.3 \ kJ/mol$ and $-219.0 \ kJ/mol$,respectively. Calculate the enthalpy of transition for the process: $PbO \text{ (yellow)} \rightarrow PbO \text{ (red)}$ in $kJ/mol$.

Enthalpy of formation of methane is $-75 \ kJ / mol$. What is the enthalpy change for formation of $24 \ g$ of methane (in $kJ$)?

The enthalpy change $(\Delta H)$ for the neutralisation of $1 \ M \ HCl$ by caustic potash in dilute solution at $298 \ K$ is ..... $kJ$.

From the following data,the heat of transition for the conversion of rhombic sulfur $(S_R)$ to monoclinic sulfur $(S_M)$ in $kJ$ is:
$S_R + O_{2(g)} \to SO_{2(g)}; \Delta H = -296.90 \ kJ$
$S_M + O_{2(g)} \to SO_{2(g)}; \Delta H = -299.40 \ kJ$