Use bond enthalpy values to calculate the enthalpy change for the following reaction. Then, label if the reaction is endothermic or exothermic
CH4 (g) + Br2 (g) —> CH3Br (g) + HBr (g)
-H -H
H-C-H Br - Br H- C-Br
-H -H
H - Br
Bond Breaking Bond making
————————————————
——————————
C-H (413 kJ/mol) C-Br (290 kJ/mol)
H-Br (366 kJ/mol) H-Br (366 kJ/mol)
Enthalpy change = (413 + 366) - (290 + 366) = 739 - 656 = 83 kJ/mol
This reaction is exothermic.