From the given diagram, the enthalpy change $\Delta_r H$ for the reaction $C \rightarrow A$ is:

Average $C-H$ bond energy is $416 \ kJ \ mol^{-1}$. Which of the following is correct?

The value of the enthalpy of neutralization of an acid and a base is significant only when $......$

Which of the following reactions can be used to define the standard enthalpy of formation of $CO_{2_{(g)}}$?

The standard enthalpy of formation of liquid water at $25^{\circ} C$ is approximately:
$H_{2(g)} + \frac{1}{2} O_{2(g)} \longrightarrow H_2O_{(l)}$

Enthalpies of formation of $CO_{(g)}$,$CO_{2(g)}$,$N_2O_{(g)}$ and $N_2O_{4(g)}$ are $-110$,$-393$,$81$ and $9.7 \, kJ \, mol^{-1}$ respectively. Find the value of $\Delta_r H$ for the reaction:
$N_2O_{4(g)} + 3 CO_{(g)} \rightarrow N_2O_{(g)} + 3 CO_{2(g)}$