Module 2

Question 1

What are the single phase regions?

Answer 1

Solid, (compressed) Liquid, (super-heated) Vapor

Question 2

A pure substance may exist in what three phases?

Answer 2

Solid, liquid and vapor

Question 3

what are the 3 most common phase diagrams used in thermodynamics?

Answer 3

P-v, P-T & T-v diagrams

Question 4

What are two phase regions? And how are they distinguished?

Answer 4

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.

Question 5

What is meant by Triple point?

Answer 5

This is the point at which the three phases coexist in equilibrium.

Question 6

What is the temperature on the vaporization line called? and what happens at this temperature?

Answer 6

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.

Question 7

What is meant by Critical Point?

Answer 7

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.

Question 8

What is the state called when P>Pc? What happens when this is the case?

Answer 8

Super-critical state. Liquid and vapor cannot coexist in equilibrium.

Question 9

What is the state called when P

Answer 9

Sub-critical state. Liquid and vapor can coexist in equilibrium.

Question 10

What name is given to the liquid state of a substance? why?

Answer 10

Compressed liquid or super-cooled liquid, this is because at a given pressure, P>Psat and T

Question 11

What name is given to the vapor state of a substance? why?

Answer 11

Super-heated vapor. this is because at a given Pressure, T>Tsat.

Question 12

What is unique about the two phase region?

Answer 12

T=Tsat and P=Psat

Question 13

How many independent properties do you need from this list T,P,x,v,u,h,s to determine the state?

Answer 13

Two!!!

Question 14

If P>Psat or T>Tsat what is the phase?

Answer 14

Compressed Liquid

Question 15

If P=Psat or T=Tsat what is the state?

Answer 15

Two-phase Mixture

Question 16

If PTsat what is the state?

Answer 16

Super heated vapor

Question 17

If T or P and x are given then what is said about the state?

Answer 17

it is a two phase mixture if T=Tsat and P=Psat. and find vuhs for the mixture.

Question 18

If T or P and v or u,h,s are given what do you look for in the tables?

Answer 18

the values of vf, v, vg, uf, u, ug, sf, s, sg, hf, h, hg

Question 19

If v

Answer 19

Compressed liquid

Question 20

If vf

Answer 20

Two phase Mixture

Question 21

If v>vg or u>ug, h>hg, s>sg what is the state?

Answer 21

Super-heated Vapor

Question 22

What is to be assumed if the compressed liquid table is not available?

Answer 22

v≈vf, u≈uf, h≈hf, s≈sf

Question 23

What does “x” represent? and how is it calculated?

Answer 23

The vapor quality!!! x=mg/mmix . mg is mass of vapor, mmix is total mass of mixture.

Question 24

What does the fusion line represent?

Answer 24

it separates the solid and liquid phases

Question 25

What does the sublimation line represent?

Answer 25

it separates the solid and vapor phases

Question 26

What can the three phases be illustrated in?

Answer 26

a pressure-specific volume-temperature surface. PvT

Question 27

What does the Vaporization line represent?

Answer 27

separates the liquid and vapor phases.

Question 28

What does Entropy quantify?

Answer 28

it quantifies how orderly the energy of a system is distributed among its molecules.

Question 29

What id the work called when it is associated with flowing fluid?

Answer 29

Flow work.

Question 30

What is the zeroth law of thermodynamics?

Answer 30

If two bodies are in thermal equilibrium with a third, the three bodies must be in equilibrium with each other