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here is a process of the catalytic depletion of ozone:

O3(g)+ O(g)--> 2O2(g)

given the standard enthalpy change of formation of ozone is +142.67kj/mol, calculate the enthalphy change of the reaction above.

below is my rather fail  energy diagram...  I think I need the enthalphy of atomization,  which is not provided.  values given are ionization energies,  some bond energies  and standard electrode potentials.  (in the data booklet ). in such  a case,  how to approach this question? 

thank you!