1. A system consists of liquid nitrogen in equilibrium with nitrogen vapor. How many phases are present? The system undergoes a process during which all of the liquid is vaporized. Can the system be viewed as a pure substance during the process? Explain.
2. An open container of pure ethanol (ethyl alcohol) liquid is placed on a table in a room. Evaporation occurs until all of the ethanol is gone. Where did the alcohol go? If the ethanol liquid and the room air are taken to be a closed system, can the system be regarded as a pure substance during the process? How many phases are present initially and finally? Explain