CHM 2045C Module Seven Sample Exam
Module 7 Part I: Heat of Reaction from Bond Energies
Methane burns in oxygen to produce heat for homes by the following reaction:
CH4 +
2 O2 è CO2 + 2 H2O
If the average bond energies in kJ/mol are:
O-O 146
O=O 498
O-H 463
C-C 346
C-H 413
C-O 358
C=O 745
H-H 436
Calculate ∆Horxn for the reaction:
ΔHorxn = Σ (bonds broken) – Σ (bonds formed)