In the reaction, C + O₂ → CO₂; ΔH = -94 kcal. What is the heat content (enthalpy) of O₂?

Solution (By Examveda Team)

The enthalpy of formation of an element in its pure state is zero .since it doesn’t require any energy to obtain this state ($$form$$) it is naturally occurring state of the element.
\[\begin{array}{l} {O_2}\left( g \right) \to {O_2}\left( g \right)\\ \Rightarrow \Delta H = 0 \end{array}\]