If the standard heat of the reaction $Fe_2O_{3(s)} + 3CO_{(g)} = 2Fe_{(s)} + 3CO_{2(g)}$ is $-6.6 \, kcal$,then $\Delta H_f^o$ for $Fe_2O_{3(s)}$ is $...... \, kcal/mol$. [Given: $\Delta H_f^o$ of $CO_{(g)} = -26.4 \, kcal$ and $\Delta H_f^o$ of $CO_{2(g)} = -94 \, kcal$]

For the reaction $N_2 + 3 X_2 \longrightarrow 2 NX_3$,where $X = F, Cl$ (the average bond energies are $F-F = 155 \ kJ \ mol^{-1}$,$N-F = 272 \ kJ \ mol^{-1}$,$Cl-Cl = 242 \ kJ \ mol^{-1}$,$N-Cl = 200 \ kJ \ mol^{-1}$ and $N \equiv N = 941 \ kJ \ mol^{-1}$),the heats of formation of $NF_3$ and $NCl_3$ in $kJ \ mol^{-1}$,respectively,are closest to

Given that $C + O_{2} \longrightarrow CO_{2} ; \Delta H^{\circ} = -x \ kJ$ and $2 CO + O_{2} \longrightarrow 2 CO_{2} ; \Delta H^{\circ} = -y \ kJ$. The heat of formation of carbon monoxide will be

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 ............... $kJ \ mol^{-1}$.

Calculate the standard enthalpy change for the following reaction: $2C_2H_6(g) + 7O_2(g) \rightarrow 4CO_2(g) + 6H_2O(l)$. Given: $\Delta_f H^{\circ}(C_2H_6) = -85 \text{ kJ mol}^{-1}$, $\Delta_f H^{\circ}(CO_2) = -390 \text{ kJ mol}^{-1}$, $\Delta_f H^{\circ}(H_2O) = -285 \text{ kJ mol}^{-1}$. (in $\text{ kJ}$)

The heat evolved in the combustion of benzene is given by the equation $C_6H_{6(l)} + 7.5 O_{2(g)} \to 3H_2O_{(l)} + 6CO_{2(g)}$,$\Delta H = -781.0 \ kcal \ mol^{-1}$. Which of the following quantities of heat energy will be evolved when $39 \ g$ of benzene is burnt in an open container?