$C + \frac{1}{2} O_2 \to CO; \Delta H = -42 \ kJ$
$CO + \frac{1}{2} O_2 \to CO_2; \Delta H = -24 \ kJ$
The heat of formation of $CO_2$ is ..... $kJ$.

If the heat of formation of $CO_2$ is $-393 \ kJ/mol$,the amount of heat evolved in the formation of $0.156 \ kg$ of $CO_2$ is.....$kJ$.

If the enthalpy change during the combustion of benzene is $-3264.6 \ kJ/mol$,then the heat produced by the combustion of $39 \ g$ of benzene is ...... $kJ$.

Given the thermochemical reactions: $C(\text{graphite}) + \frac{1}{2}O_2 \rightarrow CO; \Delta H = -110.5 \, kJ$ and $CO + \frac{1}{2}O_2 \rightarrow CO_2; \Delta H = -283.2 \, kJ$. Calculate the heat of reaction for $C(\text{graphite}) + O_2 \rightarrow CO_2$ in $kJ$.

With the help of the following data,find out the change in heat content for the reaction in $kJ$:
$C_2H_{4(g)} + H_{2(g)} \to C_2H_{6(g)}$

Bond	Bond energy $(kJ \ mol^{-1})$
$C-H$	$413$
$C-C$	$348$
$C=C$	$610$
$H-H$	$436$

The heat of neutralisation of an acid by a base is highest when: