A specific endothermic reaction structurally defined as operates with a forward activation energy me — Chemical Kinetics Chemistry Question
Question
A specific endothermic reaction structurally defined as $A \rightarrow B$ operates with a forward activation energy measured rigorously at $E_{a(f)} = 50 \text{ kJ mol}^{-1}$. If the total overall enthalpy change for this chemical reaction evaluates to $\Delta H = +20 \text{ kJ mol}^{-1}$, calculate the exact activation energy of the reverse reaction $E_{a(b)}$ in $\text{kJ mol}^{-1}$.
💡 Solution & Explanation
The fundamental thermodynamic and kinetic potential energy link dictates that the Enthalpy of reaction $\Delta H = E_{a(f)} - E_{a(b)}$. We are supplied with an endothermic $\Delta H$ of $+20 \text{ kJ mol}^{-1}$ and a forward activation barrier of $50 \text{ kJ mol}^{-1}$. Substituting these parameters directly yields: $20 = 50 - E_{a(b)}$. Rearranging immediately provides $E_{a(b)} = 50 - 20 = 30 \text{ kJ mol}^{-1}$.