Which of the following reactions defines the standard enthalpy of combustion,$\Delta H_c^ \circ$?

Find the bond enthalpy of $N-H$ bond in ammonia by using the change in enthalpy for the reaction given below: $N_{2(g)} + 3H_{2(g)} \to 2NH_{3(g)}$; $\Delta H = -23 \ kcal$. Given bond energies: $N \equiv N = 226 \ kcal/mol$,$H-H = 103 \ kcal/mol$.

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.
$3C_2H_{2(g)} \to C_6H_{6(g)}$
......$kJ \ mol^{-1}$

From Kirchhoff's equation,which factor affects the heat of reaction?

When $6.0 \ g$ of graphite reacts with dihydrogen to give methane gas,$37.4 \ kJ$ of heat is liberated. What is the standard enthalpy of formation of $CH_{4(g)}$?

The reaction of methanol $(\Delta H_f^o = -238.7 \ kJ \ mol^{-1})$ with $2$-methylpropene produces methyl tert-butyl ether $(\Delta H_f^o = -313.6 \ kJ \ mol^{-1})$. Given the reaction: $(CH_3)_2C = CH_2 + CH_3OH \rightarrow (CH_3)_3C - OCH_3; \Delta H^o = -57.8 \ kJ \ mol^{-1}$,calculate the $\Delta H_f^o$ for $2$-methylpropene.