Chemistry Question, Need some help to figure this one out

Question

Use the bond energies provided to estimate ΔH°rxn (in kJ) for the reaction below.

XeF2 + 2 F2 → XeF6

Bond Bond energy (kJ/mol)
Xe-F 147
F-F 159
Answer: kJ ?

Answer 1

Reaction: XeF₂ + 2F₂ → XeF₆

 

 

We have to break 2 Xe-F bonds in XeF₂:

 

XeF₂ → Xe + 2F   D = 2(147 kJ/mol) = 294 kJ/mol

 

 

We have to break 2 F-F in 2F₂:

 

F₂ → 2F   D = 2(159 kJ/mol) = 318 kJ/mol

 

 

We form 6 Xe-F bonds to get XeF₆:

 

Xe + 6F → XeF₆   H = 6(-147 kJ/mol) = -882 kJ/mol

 

 

Therefore, ΔH_rxn = 294 + 318 + (-882) = -270 kJ/mol

 

For 1 mole of XeF₂, ΔH_rxn = -270 kJ.