For the reaction $OF_{2(g)} \to O_{(g)} + 2F_{(g)}$,$\Delta_{rxn}H$ is $368 \ kJ$. What is the average $O-F$ bond energy in $kJ/mol$?

Given:
$2C + 2O_2 \to 2CO_2 : \Delta H = -787 \text{ kJ}$
$H_2 + \frac{1}{2}O_2 \to H_2O : \Delta H = -286 \text{ kJ}$
$C_2H_2 + \frac{5}{2}O_2 \to 2CO_2 + H_2O : \Delta H = -1310 \text{ kJ}$
Calculate the heat of formation of acetylene $(C_2H_2)$ in $\text{kJ}$.

Calculate the enthalpy change for the reaction $H_{2(g)} + Br_{2(g)} \rightarrow 2HBr_{(g)}$ in $kJ$. The bond energies of $H-H$,$Br-Br$,and $H-Br$ are $435$,$192$,and $364 \, kJ \, mol^{-1}$ respectively.

Enthalpy of formation of two compounds $X$ and $Y$ are $-84 \ kJ$ and $-156 \ kJ$ respectively. Which of the following statements is correct?

Given:
$(I) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(l)}; \Delta H^o_{298\ K} = -285.9 \ kJ \ mol^{-1}$
$(II) \ H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(g)}; \Delta H^o_{298\ K} = -241.8 \ kJ \ mol^{-1}$
The molar enthalpy of vaporisation of water will be $kJ \ mol^{-1}$.

Which of the following is an exothermic reaction?