Question

I've checked my question. Consider an ionic compound, MX , composed of generic metal M and generic, gaseous halogen X . The enthalpy of formation of MX is = - 5 3 1 kj/mol . The enthalpy of sublimation of m is � � s u b = 1 1 3 � � � � � . The ionization energy of � is IE = 4 1 3 � � � � � . The electron affinity of � is � � � � = - 3 4 9 � � � � � . ( Refer to the hint. ) The bond energy of � 2 is � � = 2 4 1 � � � � � . Determine the lattice energy of MX .

Answer 1

The lattice energy (U) of the ionic compound MX is -113 kJ/mol, signifying an exothermic process in the formation of the compound.

The lattice energy (U) of an ionic compound can be determined using the Born-Haber cycle, which involves various enthalpy changes in the formation of the compound from its elements. The relationship is given by the equation:

U = ΔHf + ΔHsub + IE + ΔHea + 1/2 × BE

Given:

Enthalpy of formation (ΔHf) of MX = -531 kJ/mol

Enthalpy of sublimation (ΔHsub) of M = 113 kJ/mol

Ionization energy (IE) of M = 413 kJ/mol

Electron affinity (ΔHea) of X = -349 kJ/mol

Bond energy (BE) of X2 = 241 kJ/mol

Substitute these values into the formula:

U = -531 kJ/mol + 113 kJ/mol + 413 kJ/mol - 349 kJ/mol + 1/2 × 241 kJ/mol

U = -113 kJ/mol

The negative sign indicates that the process of forming the ionic compound MX is exothermic, releasing energy. The magnitude of the lattice energy is 113 kJ/mol.