△H E 2E C≡C1Br-Br21C-H (2E +E C-BrC=C +2Bcn=835.1+188.3-2×284.5-610 =-155.6KJ/mol AH=ECEC-EC-C-EC-C =835.1-610-345.6=-120.5KJ/mol6、利用共价键的键能计算如下反应在2500C气态 下的反应热. ⑴ CH ≡ CH + Br2 CHBr=CHBr ΔH= ? ΔHФ= EC≡C+EBr-Br+2EC-H –(2EC-Br+EC=C +2EC-H ) =835.1+188.3–2×284.5-610 =-155.6KJ/mol （2）2 CH ≡ CH CH2 =CH — C ≡ C H ΔH= ? ΔHФ=EC≡C–EC=C –EC–C =835.1-610-345.6=-120.5KJ/mol