PPT Slide
- _E does not depend on how the change takes place, only on the initial and final states of the system.
- A system in its initial state consists of one mole of octane together with enough oxygen for its combustion.
- Some energy from the fuel mixture is released to heat and/or do work on the surroundings, so _E is negative.
- If octane is burned in the open, the energy change appears mostly as heat.
- In an automobile engine, a much larger portion (~30%) of the energy change appears as work.