Calculate reaction enthalpy using bond dissociation energies
| Bond Type | Energy (kJ/mol) | Bond Type | Energy (kJ/mol) |
|---|---|---|---|
| H-H | 436 | C-H | 414 |
| O=O | 498 | O-H | 463 |
| N≡N | 946 | N-H | 389 |
| C-C | 346 | C-O | 358 |
| C=C | 602 | C=O | 745 |
| C≡C | 835 | C≡O | 1072 |
| Cl-Cl | 243 | H-Cl | 431 |
| Br-Br | 193 | H-Br | 366 |
Always requires energy input (endothermic). Positive energy value.
Always releases energy (exothermic). Negative energy value.
ΔH = Energy to break bonds - Energy to form bonds