1. Silver chloride is an ionic compound formed by the reaction of solid silver with gas phase chlorine:

Ag(s) + ½Cl2(g)  AgCl(s)

a. Use the following information to construct a Born Haber cycle for the formation of silver chloride, AgCl. Your cycle does not need to be drawn to scale.

Name of Enthalpy Change, Equation, H0 / kJ mol-1
Enthalpy of atomisation of chlorine ½Cl2(g) – Cl(g) +121
Electron affinity of chlorine Cl(g) + e- – Cl-(g) -364
Enthalpy of atomisation of silver Ag(s) – Ag(g) +289
First ionisation enthalpy of silver Ag(g) – Ag+(g) + e- +732
Enthalpy of formation of silver chloride Ag(s) + Cl2(g) – AgCl(s) -127
Lattice dissociation enthalpy AgCl(s) ¬- Ag+(g) + Cl-(g) ?

b. Apply the H values from the table to your Born-Haber cycle to calculate the lattice dissociation enthalpy for silver chloride.
c. Calculate the bond enthalpy of a Cl–Cl bond.

d. Explain how you would expect the lattice dissociation enthalpy of silver bromide to be different from the value you have just calculated for silver chloride.

e. Explain how you would expect the lattice dissociation enthalpy of silver oxide to be different from the value you have just calculated for silver chloride.
2. Magnesium chloride is an ionic compound formed by the reaction of solid magnesium with gas phase chlorine:
Mg(s) + Cl2(g)  MgCl2(s)

a. Use the following information to construct a Born Haber cycle for the formation of magnesium chloride, MgCl2. Your cycle does not need to be drawn to scale.

Name of Enthalpy Change H / kJ mol-1
Enthalpy of atomisation of chlorine +121
Electron affinity of chlorine -364
Enthalpy of atomisation of magnesium +150
First ionisation enthalpy of magnesium +736
Enthalpy of formation of magnesium chloride -642
Enthalpy of lattice formation of magnesium chloride -2493

b. Apply the H values from the table to your Born-Haber cycle to calculate the second ionisation enthalpy of magnesium.
1.1
c. Explain how you would expect the lattice dissociation enthalpy of sodium chloride to be different from the value given for magnesium chloride.

d. Explain how you would expect the lattice dissociation enthalpy of calcium chloride to be different from the value given for magnesium chloride.