Given the following thermodynamic data for the formation of : , , , , . What is the heat of formatio — Chemical Bonding Chemistry Question

Question

Given the following thermodynamic data for the formation of $AX_3(s)$: $\Delta H_{sub} (A) = 100 \text{ kcal/mol}$, $\sum IE_{1,2,3} (A) = 490 \text{ kcal/mol}$, $\Delta H_{diss} (X_2) = 80 \text{ kcal/mol}$, $\Delta H_{eg} (X) = -110 \text{ kcal/mol}$, $\Delta H_{lattice} (AX_3) = -470 \text{ kcal/mol}$. What is the heat of formation ($\Delta H_f$) of $AX_3(s)$?