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stacker
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Homework Statement
What is the lattice energy of KI? Given the information below.
Heat of formation for KI = -328 kJ/mol
Heat of sublimation for K = 89.20 kJ/mol
Ionization energy for K = 419 kJ/mol
Bond dissociation energy for I2 = 149 kJ/mol
Electron affinity for I = - 295 kJ/mol
Heat of sublimation for I2 = 48.30 kJ/mol
I used Born-Haber's law: Delta H of formation = .5*Delta Dissociation + Delta H of sublimation + Ionization Energy + Electron Affinity + Lattice Energy
Homework Equations
Born-Haber's law = Delta H of formation = .5*Delta Dissociation + Delta H of sublimation + Ionization Energy + Electron Affinity + Lattice Energy
The Attempt at a Solution
I used Born-Haber's law: Delta H of formation = .5*Delta Dissociation + Delta H of sublimation + Ionization Energy + Electron Affinity + Lattice Energy
-328 = (89.20 - 48.30) + .5 (149) + 419 - 295 + Lattice Energy
Lattice Energy = -567.4 (Which is wrong; it should be a positive answer)