Chapter 5, Problem 49PS

The enthalpy changes for the following reactions can be measured:

CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(g)

Δ_rH° = −802.4 kJ/mol-rxn

CH₃OH(g) + $\raisebox{1ex}{$3$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$ O₂(g) → CO₂(g) + 2 H₂O(g)

Δ_rH° = −676 kJ/mol-rxn

1. (a) Use these values and Hess’s law to determine the enthalpy change for the reaction

   CH₄(g) + ½ O₂(g) → CH₃OH(g)

2. (b) Draw an energy level diagram that shows the relationship between the energy quantities involved in this problem.