Given the data below (taken from standard data tables), calculate the crystal lattice energy for sodium oxide: (remember to ALWAYS enter units as well as numerical values) ΔHf° (Na2O(s) ) = –413 kJ/mol E.A.1(O) = –133 kJ/mol E.A.2(O) = 247 kJ/mol B.D.E. (O2) = 495 kJ/mol I.E.1(Na) = 495.5 kJ/mol

Formula Formula Bond dissociation energy (BDE) is the energy required to break a bond, making it an endothermic process. BDE is calculated for a particular bond and therefore consists of fragments such as radicals since it undergoes homolytic bond cleavage. For the homolysis of a X-Y molecule, the energy of bond dissociation is calculated as the difference in the total enthalpy of formation for the reactants and products. X-Y → X + Y BDE = Δ H f X + Δ H f Y – Δ H f X-Y where, ΔHf is the heat of formation.