The enthalpy of formation (in kcal/mol) of liquid is — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

Target reaction: $\text{N}_2\text{(g)} + 2\text{H}_2\text{(g)} \to \text{N}_2\text{H}_4\text{(l)}$. Using the calculated combustion enthalpy from the previous question along with standard formation of water (from reversing eq d), the formation enthalpy evaluates directly to $+12.2\text{ kcal/mol}$.