From the given reaction,$N_{2(g)} + 3H_{2(g)} \longrightarrow 2NH_{3(g)} \quad \Delta H = -92.6 \ kJ$,the enthalpy of formation of $NH_3$ is (in $kJ$):

The combustion of carbon produces two oxides,$CO$ and $CO_2$,respectively. Their enthalpies of formation are $26 \ kcal$ and $94.3 \ kcal$ respectively. What is the enthalpy of combustion of carbon in $kcal$?

Average bond enthalpy of water is $464.5 \text{ kJ mol}^{-1}$. If the energy required to break the first $O-H$ bond is $502 \text{ kJ mol}^{-1}$,how much energy per mol is required to break the second $O-H$ bond?

What is the enthalpy change for the reaction $NaOH_{(aq)} + HCl_{(aq)} \rightarrow NaCl_{(aq)} + H_2O_{(l)}$ called?

When $2 \ mol$ of $C_2H_{6(g)}$ is completely combusted,it releases $3129 \ kJ$ of heat. What is the enthalpy of formation of $C_2H_{6(g)}$? The $\Delta H_f$ values for $CO_{2(g)}$ and $H_2O_{(l)}$ are $-395 \ kJ \ mol^{-1}$ and $-286 \ kJ \ mol^{-1}$ respectively.

If the enthalpies of combustion of benzene $(l)$,carbon $(s)$,and hydrogen $(g)$ are $Q_1$,$Q_2$,and $Q_3$ respectively,what will be the enthalpy of formation of benzene?