Solution: Use bond enthalpies in the table below to estimate H for each of the following reactions. 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