A Born Haber cycle is used to determine lattice energy because it
- A. measures lattice energy directly in a calorimeter
- B. applies Hess's law to relate lattice energy to quantities that can be measured
- C. predicts the shape of the crystal
- D. measures the melting point of the ionic solid
Explanation
Lattice energy cannot be measured in an experiment, so the cycle links it to the enthalpy of atomisation, ionisation energy, electron affinity and enthalpy of formation, all of which can. Because enthalpy is a state function the total around the cycle is zero regardless of the route, which is Hess's law applied to ionic compounds. A large discrepancy between calculated and experimental values indicates covalent character.