Write out and balance the combustion reaction of methane using integer coefficients. Use the average bond energies given to calculate the energy change (in kJ) for this balanced combustion reaction

Question

Averange bond strengths:

C-C	350
C=O (in CO2)	804
O=O (in O2)	498
O-H	464
C-H	415

Answer 1

CH4 + O2 yields CO2 + H2O

Balance:

CH4 + 2O2 yields CO2 + 2H2O

Reactants:

4 C-H = 4(415) = 1660

2 O=O = 2(498) = 996

Sum = 2656

Products:

2 C=O = 2(804) = 1608

2 times 2 O-H(464) = 1856

Sum = 3464

2656 - 3464 = -808 kJ per mole methane (energy released: exothermic)