When $2 \, mol$ of $C_2H_6$ is completely combusted,$3129 \, kJ$ of heat is released. The heat of formation of $C_2H_6$ is ..... $kJ/mol$. Given that $\Delta H_f$ for $CO_2$ and $H_2O$ are $-395 \, kJ/mol$ and $-286 \, kJ/mol$ respectively.

Given that $C_{(g)} + 4H_{(g)} \to CH_{4(g)}; \Delta H = -166 \ kJ$,the bond energy of the $C-H$ bond will be....$kJ/mole$.

For the reaction $F_2 + 2HCl \rightarrow 2HF + Cl_2$,the $\Delta H^o$ is $-352.8 \ kJ$. If the $\Delta H_f^o$ for $HF$ is $-268.3 \ kJ \ mol^{-1}$,then the $\Delta H_f^o$ for $HCl$ will be . . . . . . $kJ \ mol^{-1}$.

Calculate the amount of methane formed by the liberation of $149.6 \ kJ$ of heat using the following equation:
$C_{(s)} + 2H_{2(g)} \longrightarrow CH_{4(g)} \quad \Delta H = -74.8 \ kJ/mol$ (in $g$)

If the heat of combustion of $C$ is $-x \, kJ$,the heat of formation of $H_2O$ is $-y \, kJ$,and the heat of combustion of $CH_4$ is $-z \, kJ$,what is the heat of formation of $CH_4$?

Consider the reaction $2H_2S(g) + 3O_2(g) \rightarrow 2H_2O(l) + 2SO_2(g)$. The magnitude of enthalpy change for the reaction in $\text{kJ mol}^{-1}$ is . . . . . . . (Nearest integer). Given: $\Delta_f H^\circ(H_2S) = -20.1 \text{ kJ mol}^{-1}$, $\Delta_f H^\circ(H_2O) = -286.0 \text{ kJ mol}^{-1}$, $\Delta_f H^\circ(SO_2) = -297.0 \text{ kJ mol}^{-1}$