- #1
Red_CCF
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Hello
I’m wondering if my understanding of how different processes relate to the phase diagram here is correct.
1) If a piston cylinder assembly maintains a constant 1atm pressure on some water and the water is cooled, we would be going horizontally along the red line from 373.15K to 273.15K at 1atm and the system will only have one phase at any point in the process?
2) If I have a cup of water exposed to air, assuming the air is saturated at all times, cooling the water from say 373.15K means we are following the saturation (black) line separating liquid-vapor until the triple point? What effect does total air pressure play in this?
3) For 2), what if the vapour pressure is not saturated (some sort of venting carrying it away)?
4) Is there a formal definition for what pressure in the phase diagram is? For a single phase closed system I see it as the pressure held by the container, but what about for a multiphase system?
Thank you very much
I’m wondering if my understanding of how different processes relate to the phase diagram here is correct.
1) If a piston cylinder assembly maintains a constant 1atm pressure on some water and the water is cooled, we would be going horizontally along the red line from 373.15K to 273.15K at 1atm and the system will only have one phase at any point in the process?
2) If I have a cup of water exposed to air, assuming the air is saturated at all times, cooling the water from say 373.15K means we are following the saturation (black) line separating liquid-vapor until the triple point? What effect does total air pressure play in this?
3) For 2), what if the vapour pressure is not saturated (some sort of venting carrying it away)?
4) Is there a formal definition for what pressure in the phase diagram is? For a single phase closed system I see it as the pressure held by the container, but what about for a multiphase system?
Thank you very much