Given the bond dissociation energies below (in kcal/mol), es…

Given the bond dissociation energies below (in kcal/mol), estimate the ΔH° for the propagation step CH3CH2CH2—H                     98(CH3)2CH—H                            95Cl—Cl                                           58H—Cl                                            103CH3CH2CH2—Cl                      81(CH3)2CH—Cl                             80