# Problem: What is the enthalpy of sublimation for K, in kJ/mol?Given:Lattice energy of KCl = 699 kJ/molFirst ionization energy of K = 418.7 kJ/molElectron affinity of Cl = 349 kJ/molBond energy of Cl-Cl = 242.7 kJ/molEnthalpy of formation of KCl = -435.87 kJ/mol

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###### FREE Expert Solution

We’re being asked to calculate the heat of sublimation of potassium (K), given the lattice energy of KCl.

Recall that lattice energy is the energy required to combine two gaseous ions into a solid ionic compound:

Mx+(g) + Ny–(g)  MyNx(s)

To calculate for lattice energy, we need to do the Born-Haber cycle for KCl

K(s) + ½ Cl2(g)  KCl(s), ΔH˚f

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###### Problem Details

What is the enthalpy of sublimation for K, in kJ/mol?

Given:

Lattice energy of KCl = 699 kJ/mol

First ionization energy of K = 418.7 kJ/mol

Electron affinity of Cl = 349 kJ/mol

Bond energy of Cl-Cl = 242.7 kJ/mol

Enthalpy of formation of KCl = -435.87 kJ/mol

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Born Haber Cycle concept. You can view video lessons to learn Born Haber Cycle Or if you need more Born Haber Cycle practice, you can also practice Born Haber Cycle practice problems .

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Based on our data, we think this problem is relevant for Professor Albright's class at UMICH.