If the bond energies of $H-H$,$Br-Br$ and $H-Br$ are $433$,$192$ and $364 \ kJ \ mol^{-1}$ respectively,then $\Delta H^{\circ}$ for the reaction: $H_{2(g)} + Br_{2(g)} \rightarrow 2HBr_{(g)}$ is:

The $\Delta H_f^o$ values for $ICl_{(g)}$,$Cl_{(g)}$,and $I_{(g)}$ are $17.57$,$121.34$,and $106.96 \, J \, mol^{-1}$ respectively. What is the bond dissociation energy of the $I-Cl$ bond in $J \, mol^{-1}$?

Calculate the change in enthalpy when $39 \ g$ of acetylene is completely burnt with oxygen,given that the enthalpy of combustion of acetylene is $1300 \ kJ \ mol^{-1}$. (in $kJ$)

The compounds with negative heat of formation are known as:

Given: $S + O_2 \rightarrow SO_2 : \Delta H_1 = -298.2 \ kJ$,$SO_2 + 1/2 \ O_2 \rightarrow SO_3 : \Delta H_2 = -98.7 \ kJ$,$SO_3 + H_2O \rightarrow H_2SO_4 : \Delta H_3 = -130.2 \ kJ$,and $H_2 + 1/2 \ O_2 \rightarrow H_2O : \Delta H_4 = -287.3 \ kJ$. Calculate the heat of formation of $H_2SO_4$ in $kJ$.

Given that the bond energy of hydrogen-hydrogen bond is $436 \ kJ/mol$,that of hydrogen-oxygen bond is $464 \ kJ/mol$,and those in oxygen molecules $496 \ kJ/mol$,what is the approximate heat of reaction for $2H_2 + O_2 \longrightarrow 2H_2O$ ? .....$kJ/mol$