MECHENG 235 Lecture Notes - Lecture 2: Specific Volume, Triple Point, Intensive And Extensive Properties

• School: U of M
• Department: Mechanical Engineering
• Course: MECHENG 235
• Professor: Jason Martz

Document Summary

Pure substance- a substance with homogeneous and invariable chemical composition. May have more than one phase, but composition is the same throughout. For a simple pure substance, the state is defined by two independent, intensive properties. Once the state is fixed, you know each and every property associated with that state. At (b) it is boiling with co-existing liquid and vapor. B c (c) further heating gives warm vapor. If water is cooled it will change state from (a) towards (e) and it will start to freeze at (d) Further cooling gives solid water (ice) with no liquid at (e) If process is repeated at different pressures we can indicates the phases in a p-t diagram, where the points for the phase changes are connected with red curves. On the red curves points are pairs of saturated (p,t) Triple point- all three phases at once - where the three lines intersect.