I am glad we are moving in the right direction. The oxygen in the air is heavier than the nitrogen, but it doesn't settle to the bottom of the room. You could think for instance of breaking apart atoms and recombining them, or building a new person cell by cell. Very difficult, indeed, and far beyond what man is capable of, but not impossible. By the way, the gas separation is easy.
All gases have different freezing and boiling points.
A little confusion at first with the Chapter 7 questions, but I think it'll be cleared up in the next two lectures. I think it will be. If you can make it through the three difficult aspects of the SFEE, reversible and irreversible processes will be easy. I will talk about this in lecture, but if you are interested now read this . This is an improvement over last lecture.