I would like to know how to do the following problem (would you use the Born-Haber cycle?)
the value of the second ionization energy for Ca, 1145 kJ/mol, calculate the lattice energy of CaF2.
you need to use Born Haber's cycle
Ca(s) ---> Ca(g ) (Sublimation enthalpy in KJ per mole )
Ca(g)---.>Ca+1(g ) +1e(first ionization energy in KJ/mol)
Ca+1(g ) ----> Ca+2(g ) +1e(second ionization energy in K J/mol)
F2 (g) ------>2F (g) (Bond enthalpy in KJ /mol)
2F + 2e------>2 F-1(g) (2x electron affinity in KJ/mol)
Ca+2(g )+ 2 F-1(g) ----> CaF2(s) ( lattice energy in KJ/mol)
to get the desired equation
Ca(s) + F2(g) ---> CaF2(s)
add all the enthalpies with proper signs
Try it now