Review | Constants | Periodic Table Average Bond Dissociation Energies, D (kJ/mol) H−H 436 C−H 410 N−H 390 O−F 180 I−I 151 H−C 410 C−C 350 N−C 300 O−Cl 200 S−S 310 H−F 570 C−F 450 N−F 270 O−Br 210 S−Cl 250 H−Cl 432 C−Cl 330 N−Cl 200 O−I 220 S−Br 210 H−Br 366 C−Br 270 N−Br 240 O−N 200 S−S 225 H−I 298 C−I 240 N−N 240 O−O 180 H−N 390 C−N 300 N−O 200 F−F 159 H−O 460 C−O 350 O−H 460 Cl−Cl 243 H−S 340 C−S 260 O−C 350 Br−Br 193 Multiple covalent bonds C=C 728 C≡C 965 C=O 732 O−O 498 N≡N 945 Part A Use the bond dissociation energies from the table above to calculate an approximate ΔH∘ in kilojoules for the reaction of acethylene with hydrogen to yield ethane. HC≡CH(g)+2H2(g)→CH3CH3(g)