12.2 a) Calculate the lattice energyof RbBr(s) using the following thermodynamicdata (all data is in kJ/mol). Note that the data given has beenperturbed, so looking up the answer is probably not a goodidea.

Rb(s)	ΔHsublimation = 61 kJ/mol
Rb(g)	Ionization energy = 383 kJ/mol
Br-Br(g)	Bond energy = 173 kJ/mol
Br(g)	Electron affinity = -345 kJ/mol
RbBr(s)	ΔH°f = -415 kJ/mol

kJ/mol

The heat of fusion of iron at itsnormal melting point of 1535°Cis 16.2 kJ/mol, while its heat ofvaporization at its normal boiling pointof 2750°Cis 354.0 kJ/mol.
b) Use these data to calculate the heat of sublimationfor Fe. kJ/mol
Is your answer precise or is itapproximate? _________preciseapproximate
c) At 298 K, the standard heat of formationof Fe(s)is 0 kJ/mol while the standard heat offormation of Fe(g)is 416.3kJ/mol. Use this to calculate theheat of sublimation of iron. kJ/mol.
Is your result for part (b) larger or smaller than the valuecalculated in part (a)? _________largersmaller