Relative Stabilities cumulated terminal diene alkyne =C- 入 1,2-pentadiene 1I-pentyne internal alkyne twice 1-pentene 69.8 2-pentyne kcal isolated 69.5 diene more substituted kcal isolated 65.8 1,4-pentadiene diene kcal trans-1,4-hexadiene conjugated 60.2 diene keal 57.4 trans-1,3-pentadiene kcal 53.7 kcal alkane (pentane or hexane) Chaper 15 4Chaper 15 4 Relative Stabilities twice 1-pentene more substituted =>