[Aufbau89]

How do we estimate the heat of fusion for barium Chloride Given:

          Ba(s) +   Cl₂  ->    BaCl₂(s)

Lattice energy =                                        -2056 kJ/mol
First Ionization energy of Ba=                     503 kJ/mol
Second Ionization energy of Ba=                965 kJ/mol
E- affinity of Cl=                                          -349 kJ/mol
bond energy of Cl₂=                                    239 kJ/mol
Enthalpy of sublimation of Ba=                  178 kJ/mol



-I just multiplied the E- affinity of Cl by 2 because its Cl₂ that is in the equation and added all the given energies.  I'm not sure if what i did was correct and also why I did it, can someone help explain this to me?


My work:
-2056+503+965+2(-349)+239+178= -869 kJ/mol

[Albireo]

Yeah that looks right since you use the first and second ionization energies to get Ba²⁺ to match the Cl₂ which will turn into two Cl^- with the bond energy and the Na im assuming you typoed and is a Ba which has to turn into a gas to mix with the Cl₂ and of course the lattice energy at the end to solidify the compound