I could really use some help on this one. I guess it's what I deserve leaving everything to Sunday night. Anyways, I'v looked through my book to try to find out how to do it and I'm compleatly stumped. Could you guys look at it, and if you know how to do it, explain it to me? I'd really appreciate it if you could. Here it is:

Use the following information to estimate ∆H°f for sodium chloride.

Na(s)+ 1/2Cl2(g) → NaCl(s)

Lattice energy is –786 kJ/mol
Ionization energy for Na is 495 kJ/mol
Electron affinity of Cl is -349 kJ/mol
Bond energy of Cl2 is 239 kJ/mol
Enthalpy of sublimation for Na is 109 kJ/mol

Sorry if it's a little hard to understand, the sub-and superscript didn't follow over when I pasted it.