Use Hess’s Law and solve for the enthalpy change of the following rxn:
12 P(s) + 10 Fe2O3 (s) -> 3 P4O10 (s) + 20 Fe (s)
2 C2H6 (l) + 7 O2 (g) -> 4 CO2 (g) + 6H2O (g)
