Module 2 Flashcards
Thermodynamic Properties of a pure substance
What are the single phase regions?
Solid, (compressed) Liquid, (super-heated) Vapor
A pure substance may exist in what three phases?
Solid, liquid and vapor
what are the 3 most common phase diagrams used in thermodynamics?
P-v, P-T & T-v diagrams
What are two phase regions? And how are they distinguished?
Two phase regions are shown as lines separating different phases.
Vaporization line: separates the liquid and vapor phases.
Fusion Line: Separates the solid and liquid phases.
Sublimation line: Separates the solid and vapor phases.
What is meant by Triple point?
This is the point at which the three phases coexist in equilibrium.
What is the temperature on the vaporization line called? and what happens at this temperature?
Saturation temperature is the temperature at which evaporation or condensation takes place at a given saturation pressure. Remember, for each saturation temp there is a saturation pressure.
What is meant by Critical Point?
This is the point where saturated liquid and saturated vapor lines meet. Pressure and temperature at this point are called critical pressure and critical temperature.
What is the state called when P>Pc? What happens when this is the case?
Super-critical state. Liquid and vapor cannot coexist in equilibrium.
What is the state called when P
Sub-critical state. Liquid and vapor can coexist in equilibrium.
What name is given to the liquid state of a substance? why?
Compressed liquid or super-cooled liquid, this is because at a given pressure, P>Psat and T
What name is given to the vapor state of a substance? why?
Super-heated vapor. this is because at a given Pressure, T>Tsat.
What is unique about the two phase region?
T=Tsat and P=Psat
How many independent properties do you need from this list T,P,x,v,u,h,s to determine the state?
Two!!!
If P>Psat or T>Tsat what is the phase?
Compressed Liquid
If P=Psat or T=Tsat what is the state?
Two-phase Mixture
If PTsat what is the state?
Super heated vapor
If T or P and x are given then what is said about the state?
it is a two phase mixture if T=Tsat and P=Psat. and find vuhs for the mixture.
If T or P and v or u,h,s are given what do you look for in the tables?
the values of vf, v, vg, uf, u, ug, sf, s, sg, hf, h, hg
If v
Compressed liquid
If vf
Two phase Mixture
If v>vg or u>ug, h>hg, s>sg what is the state?
Super-heated Vapor
What is to be assumed if the compressed liquid table is not available?
v≈vf, u≈uf, h≈hf, s≈sf
What does “x” represent? and how is it calculated?
The vapor quality!!! x=mg/mmix . mg is mass of vapor, mmix is total mass of mixture.
What does the fusion line represent?
it separates the solid and liquid phases
What does the sublimation line represent?
it separates the solid and vapor phases
What can the three phases be illustrated in?
a pressure-specific volume-temperature surface. PvT
What does the Vaporization line represent?
separates the liquid and vapor phases.
What does Entropy quantify?
it quantifies how orderly the energy of a system is distributed among its molecules.
What id the work called when it is associated with flowing fluid?
Flow work.
What is the zeroth law of thermodynamics?
If two bodies are in thermal equilibrium with a third, the three bodies must be in equilibrium with each other
