Answer to Question #142749 in Physical Chemistry for Nama Glory

Question

Use the data to find another value for the enthalpy of buta-l , 3 —diene.
Bond energies Enthalpies of atomisation
C-H 413 KJ/mol C 715 KJ/mol
346 KJ/mol H 218 KJ/mol
610 KJ/mol

Answer 1

∆H_f = {Σ ∆H to turn elements into gaseous atoms -Σ ∆H to turn compound into gaseous atoms}

4C_(s) + 3H_2(g) =CH₂CHCHCH_2(g)

∆ H_f = {4x∆H_at [C] + 3 x E[H-H]) – (E[C-C] + 6 x E[C-H] +2×E(C=C)}

{4 x715+3 x2 x218-(413 x6 +2 x610 x346)} kJ/mol

∆ H_f=+124kJ/mol