Ammonia is produced directly from nitrogen and hydrogen by using the Haber process. The chemical reaction is
N2 (g) + 3H2 (g) †’ 2NH3 (g)
(a) Use Table 8.4 to estimate the enthalpy change for the reaction. Is it exothermic or endothermic?
(b) Compare the enthalpy change you calculate in (a) to the true enthalpy change as obtained using ΔHof values.

TABLE 8.4 Single Bonds e Average Bond Enthalpies (kJ/mol) C H C-C C-N _o C-F C CI C Br 413 348 293 358 485 328 276 240 259 N H N-N 391 163 201 272 200 243 463 146 190 203 234 F-F 155 O-O CI-F CI-CI 253 242 O Cl N F N-CI N Br 237 218 193 S--H BrCl 436 SF 567 431 366 299 339 327 253 218 266 S-CI SBr CS H-Cl H Br I- Cl I Br 208 175 151 Si-H SiSi SiC Si-O SiCl 323 226 301 368 464 Multiple Bonds - 614 839 615 891 799 1072 418 O 941 607 S O 495 C-N N-O 523 418 S-S