Using bond energy data, calculate the heat of formation of isoprene, CH₂=C(CH₃)–CH=CH₂. Given the bond energy of C–H = 98.8 kcal, H–H = 104 kcal, C–C = 83 kcal, C=C = 147 kcal, and Δ H of C(s) → C(g)

Question

Using bond energy data, calculate the heat of formation of isoprene, CH₂=C(CH₃)–CH=CH₂. Given the bond energy of C–H = 98.8 kcal, H–H = 104 kcal, C–C = 83 kcal, C=C = 147 kcal, and Δ H of C(s) → C(g) = 171 kcal.

TestHub · Accepted Answer

5 C ( g r a p hi t e ) + 4 H 2 ​ → C H 2 ​ = C ( C H 3 ​ ) – C H = C H 2 ​ Δ H = 5 ( 171 ) + 4 ( 104 ) – [( 147 × 2 ) + ( 83 × 2 ) + ( 8 × 98.8 )] = 20 . 6 k c a l

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