We are asked to calculate ΔH for the reaction Br2(g) → 2 Br(g).
ΔH°f Br2(g) = 30.91 kJ/mol
ΔH°f Br(g) = 111.88 kJ/mol
Note that we need to multiply each ΔH˚ by the stoichiometric coefficient since ΔH˚ is in kJ/mol.
Use enthalpies of formation given in Appendix C to calculate ΔH for the reaction Br2(g) → 2 Br(g), and use this value to estimate the bond enthalpy D(Br-Br).
|Average Bond Enthalpies (kJ/mol)|
|C-H 413||N-H 391||O-H 463||F-F 155|
|C-C 348||N-N 163||O-O 146|
|C=C 614||N-O 201||O=O 495||Cl-F 253|
|C-N 293||N-F 272||O-F 190||Cl-Cl 242|
|C-O 358||N-Cl 200||O-Cl 203||Br-F 237|
|C=O 799||N-Br 243||O-I 234||Br-Cl 218|
|C-F 485||H-H 436||Br-Br 193|
|C-Cl 328||H-F 567|
|C-Br 276||H-Cl 431||I-Cl 208|
|C-I 240||H-Br 366||I-Br 175|
|H-I 299||I-I 151|
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