Determining the Lattice Energy of MX2

Question

1. The enthalpy of formation of MX2 is -745 kJ/mol.
2. The enthalpy of sublimation of M is 143 kJ/mol.
3. The first and second ionization energies of M are IE 705 kJ/mol and IE 1403 kJ/mol.
4. The electron affinity of  is X -335 kJ/mol.
5. The bond energy of X2 is 187 kJ/mol.

Please help explain to me how I should get the answer! I have been trying to get the right answer for a few hours but don't seem to be arriving at it!

Answer 1

If you are having trouble with this type of problem, I suggest you look up and read about (or watch videos) on the Born-Haber Cycle which deals with this very topic.

LE =∆H_sub + 1st IE + 2nd IE + ∆H_diss (or bond energy) + 2xEA - ∆H_formation

LE = 143 + 705 + 1403 + 187 + (2 x -335) - (-745) = 2513 kJ/mole