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 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)