The enthalpies of formation of $Al_{2}O_{3}$ and $Cr_{2}O_{3}$ are $-1596 \ kJ$ and $-1134 \ kJ$ respectively. $\Delta H$ for the reaction $2Al + Cr_{2}O_{3} \to 2Cr + Al_{2}O_{3}$ is.......$kJ$

If bond energy for $H_{2(g)}$,$Br_{2(g)}$ and $HBr_{(g)}$ is $433$,$192$ and $364 \ kJ \ mol^{-1}$ respectively,then $\Delta H^o$ for the reaction,$H_{2(g)} + Br_{2(g)} \to 2HBr_{(g)}$ is......$kJ$.

For the reaction,$2 H_{2(g)} + O_{2(g)} \longrightarrow 2 H_{2}O_{(g)}$,$\Delta H^{\circ} = -573.2 \ kJ$. The heat of decomposition of water per mole is

If $H^{+} + OH^{-} \to H_2O + 13.7 \ kcal$,then the heat of neutralization for complete neutralization of one mole of $H_2SO_4$ by base will be.......$kcal$

Calculate the enthalpy of formation of ethylene $(C_2H_4)$ from the following data:
$(I)$ $C_{\text{(graphite)}} + O_{2(g)} \longrightarrow CO_{2(g)}$; $\Delta H = -393.5 \ kJ$
$(II)$ $H_{2(g)} + \frac{1}{2} O_{2(g)} \longrightarrow H_2O_{(l)}$; $\Delta U = -256.2 \ kJ$
$(III)$ $C_2H_{4(g)} + 3 O_{2(g)} \longrightarrow 2 CO_{2(g)} + 2 H_2O_{(l)}$; $\Delta H = -1410.8 \ kJ$ (in $kJ$)

The heat of combustion of acetaldehyde to carbon dioxide and water is $-1172 \ kJ \ mol^{-1}$. Calculate the amount of heat liberated when $66 \ g$ of acetaldehyde is completely oxidised. (Atomic mass: $C=12, H=1, O=16$) (in $kJ$)