If $\Delta H_f^o$ for $H_2O_2$ and $H_2O$ are $-188 \ kJ/mole$ and $-286 \ kJ/mole$ respectively,what will be the enthalpy change of the reaction $2H_2O_{2(l)} \to 2H_2O_{(l)} + O_{2(g)}$ in $kJ/mole$?

If the ratio of the enthalpy of formation of $CO_2$ and $SO_2$ is $4:3$ and the enthalpy of formation of $CS_2$ is $26 \ kcal/mol$,then what will be the enthalpy of formation of $SO_2(g)$ based on the following reaction?
$CS_2(l) + 3O_2(g) \to CO_2(g) + 2SO_2(g)$

When ethyne is passed through a red hot tube,the formation of benzene takes place :-
$\Delta H_{f(C_2H_2)(g)}^o = 230 \ kJ \ mol^{-1}$
$\Delta H_{f(C_6H_6)(g)}^o = 85 \ kJ \ mol^{-1}$
Calculate the standard heat of trimerisation of ethyne to benzene.
$3C_2H_{2(g)} \to C_6H_{6(g)}$
......$kJ \ mol^{-1}$

In an exothermic reaction,$\Delta H$ is

The enthalpy of atomisation for the reaction $CH_{4(g)} \to C_{(g)} + 4H_{(g)}$ is $1665 \ kJ \ mol^{-1}$. What is the bond energy of $C-H$ bond?

The combustion enthalpies of carbon,hydrogen,and methane are $-393.5 \ kJ/mole$,$-284.8 \ kJ/mole$,and $-890.4 \ kJ/mole$ respectively at $25 \ ^oC$. The value of the standard formation enthalpy of methane at that temperature is ..... $kJ/mole$.