chapter 3
properties of pure substances
what is pure substance???
A substances that has fixed chemical composition throughout is called a pure substances.
PHASE OF A PURE SUBSTANCES
PHASE-CHANGE PROCESSES OF PURE SUBSTANCES
compressed liquid = water exist in the liquid phase
saturated liquid = a liquid that is about to vaporize
saturated vapor = a vapour that is about to condense
superheated vapor = a vapour is not about to condense
PPROPERTY DIAGRAMS FOR PHASE-CHANGE PROCESSES
1) THE T-V DIAGRAM
To read and to know the values in the diagram,we must refer to table A-5 which is at the back of thermodynamics book.At the liquid-vapour saturation region,the first point of the straight is called vf-the specific volume of the liquid.at the last point of the straight is called vg-the specific volume of the vapour.All the superheated vapour states are located to the right of the saturated vapour line is called the superheated vapour region.to read the value of the superheated vapour region must to refer at A-6 table.
2)THE P-V DIAGRAM
3)THE P-T DIAGRAM
4)THE P-V-T SURFACES
ENTHALPHY-A COMBINATION PROPERTY
h=u+pv (KJ/KG)
H=U+PV (KJ)
SATURATED LIQUID AND SATURATED VAPOR STATES
Vf - specific volume of saturated liquid
Vg - specific volume of saturated vapor
Vfg - differences between Vg and Vf.
SATURATED LIQUID-VAPOR MIXTURE.
X - mvapor/mtotal
V - mv
Mtotal = Mliquid + Mvapour = Mf + Mg
COMPRESSED LIQUID
h = h + v (p2-p1)
PHASE OF A PURE SUBSTANCES
PHASE-CHANGE PROCESSES OF PURE SUBSTANCES
compressed liquid = water exist in the liquid phase
saturated liquid = a liquid that is about to vaporize
saturated vapor = a vapour that is about to condense
superheated vapor = a vapour is not about to condense
PPROPERTY DIAGRAMS FOR PHASE-CHANGE PROCESSES
1) THE T-V DIAGRAM
To read and to know the values in the diagram,we must refer to table A-5 which is at the back of thermodynamics book.At the liquid-vapour saturation region,the first point of the straight is called vf-the specific volume of the liquid.at the last point of the straight is called vg-the specific volume of the vapour.All the superheated vapour states are located to the right of the saturated vapour line is called the superheated vapour region.to read the value of the superheated vapour region must to refer at A-6 table.
2)THE P-V DIAGRAM
3)THE P-T DIAGRAM
4)THE P-V-T SURFACES
ENTHALPHY-A COMBINATION PROPERTY
h=u+pv (KJ/KG)
H=U+PV (KJ)
SATURATED LIQUID AND SATURATED VAPOR STATES
Vf - specific volume of saturated liquid
Vg - specific volume of saturated vapor
Vfg - differences between Vg and Vf.
SATURATED LIQUID-VAPOR MIXTURE.
X - mvapor/mtotal
V - mv
Mtotal = Mliquid + Mvapour = Mf + Mg
COMPRESSED LIQUID
h = h + v (p2-p1)
The ideal-gas equation of state
Any equation that relates pressure,temperature,and specific volume of a substances is called an equation state.
P = R (T/V)
PV = RT
R= Ru/M
