1. What is meant by embodied energy per kilogram of a metal?
Why does it differ from the free energy of formation of the oxide, carbonate,
or sulfide from which it was extracted?
2. Recycle energies. The aluminum window frame of Exercise
E6.2 is, in reality, made not of virgin aluminum but of 100% recycled aluminum.
Recycled PVC is not available, so the PVC window continues to use virgin
material. Which frame now has the lower embodied energy?