Table 7.1 Average Bond Dissociation Energies Bond Dissociation Bond Dissociation Bond Dissociation Energy kcal/mol (kJ/mol) Energy kcal/mol (kJ/mol) Energy Bond Bond Bond kcal/mol (kJ/mol) C-H 99 (413) N-H 93 (391) C=C 147 (614) C C 83 (347) N-N 38 (160) C=C 201 (839) C-N 73 (305) N-CI 48 (200) C=0* 178 (745) C-0 86 (358) N-0 48 (201) 119 (498) 0=0 C- CI 81 (339) H-H 103 (432) N=0 145 (607) CI-CI 58 (243) 0-H 112 (467) 0=N 213 (891) H-CI 102 (427) 0-CI 49 (203) N=N 226 (946) *The C=0 bond dissociation energies in CO2 are 191 kcal/mol (799 kJ/mol).

The reaction that was on the screen when you started and its derivative demonstrate that the reaction enthalpy, ΔH, changes sign when a process is reversed. Consider the reaction H2O(l)→H2O(g), ΔH =44.0kJ What will ΔH be for the reaction if it is reversed?

In the reaction below, how much heat is required for the creation of 38.2 g HBr? H2 + Br2 → 2 HBr ΔH = 72.80 kJ/mol

Dd.101.