Calculate the lattice enthalpy of potassium fluoride from the following data. enthalpy of formation of k(g): +89 kj · mol−1 first ionization energy of k(g): +418 kj · mol−1 enthalpy of formation of f(g): +79 kj · mol−1 electron affinity of f(g): +328 (∆h = −328) kj · mol−1 enthalpy of formation of kf(s): −567 kj · mol−1