Hess' Law states that if a reaction can occur by more than one route, the total change in enthalpy remains the same, as long as the initial and final conditions are the same.
This is a Born-Haber cycle, and uses Hess' law to indirectly calculate the lattice enthalpy of a compound by working with known enthalpy changes.
- Start- the Datum line. This is the starting point, and shows the elements in the ionic compound in their standard states with zero energy
- Route 1- the standard enthalpy of formation for the ionic compound, Lithium fluoride. This is an exothermic process, so goes down…