how do I Use the following to calculate the [delta] H°lattice of MgF2?

Question

Mg(s) Mg(g) H° = 148 kJ
F2(g) 2 F(g) H° = 159 kJ

Mg(g) Mg+(g) + e- H° = 738 kJ
Mg+(g) Mg+2(g) + e- H° = 1450 kJ

F(g) + e- F -(g) H° = -328 kJ
Mg(s) + F2(g) MgF2(s) H° = -1123 kJ


how do i do this? please explain. I do not get it

Answer 1

Here you have all but one of the components of a Born Haber Cycle. The missing component is the lattice enthalpy.

Numbering your data from 1 - 6, the answer is:

-6+1+2+3+4+(2x5)

Some definitions will have this the other way round (change all the signs) - it will depend entirely on what you've been taught.