For the reaction $C_{2}H_{6} \rightarrow C_{2}H_{4} + H_{2}$,the reaction enthalpy $\Delta_{r}H = \dots \dots \dots \dots \dots \dots \dots \dots \dots \dots \dots \dots \, kJ \, mol^{-1}$. (Round off to the Nearest Integer). [Given: Bond enthalpies in $kJ \, mol^{-1} : C-C : 347, C=C : 611, C-H : 414, H-H : 436$]

Calculate the heat of formation of ethyl alcohol in $kcal/mol$ from the following data:
$C_{(s)} + O_{2(g)} \to CO_{2(g)}, \Delta H = -94 \ kcal$
$H_{2(g)} + \frac{1}{2} O_{2(g)} \to H_2O_{(l)}, \Delta H = -68 \ kcal$
$C_2H_5OH_{(l)} + 3O_{2(g)} \to 2CO_{2(g)} + 3H_2O_{(l)}, \Delta H = -327 \ kcal$

Which of these species has a standard enthalpy of formation equal to zero?

The bond energies of $H-H$ and $Cl-Cl$ are $430 \, kJ/mol$ and $240 \, kJ/mol$ respectively. If $\Delta_f H$ for $HCl$ is $-90 \, kJ/mol$,then the bond enthalpy of $HCl$ will be ...... $kJ/mol$.

Calculate the enthalpy change for the process $CCl_{4(g)} \to C_{(g)} + 4Cl_{(g)}$ and calculate the bond enthalpy of the $C-Cl$ bond in $CCl_{4(g)}$.
$\Delta_{vap} H^{\theta}(CCl_{4}) = 30.5 \, kJ \, mol^{-1}$
$\Delta_{f} H^{\theta}(CCl_{4}) = -135.5 \, kJ \, mol^{-1}$
$\Delta_{a} H^{\theta}(C) = 715.0 \, kJ \, mol^{-1}$ (where $\Delta_{a} H^{\theta}$ is enthalpy of atomisation)
$\Delta_{a} H^{\theta}(Cl_{2}) = 242 \, kJ \, mol^{-1}$

The enthalpy of neutralisation of $NH_4OH$ and $HCl$ is numerically: