3.5 Property Table

1.  Thermodynamic properties relationships in most substance are complex
2.  calculation using the relations and measurable properties
3.  frequently presented in the form of tables e.g. steam table

Enthalpy—A Combination Property :-
The combination u + Pv is frequently encountered in the analysis of control volumes










Enthalpy of vaporization, hfg :- (Latent heat of vaporization)
The amount of energy needed to vaporize a unit
mass of saturated liquid at a given temperature
or pressure.






Quality x : The ratio of the mass of vapor to the total mass of the mixture.



- Temperature and pressure are dependent properties for a mixture.


Superheated Vapor ;-
Region to the right of the saturated vapor line, substance is in superheated vapor where temperature and pressure are independent properties.

3.6 The Ideal-gas Equation of State

•  Equation of state: Relates pressure, temperature, and specific volume of substance.
•  The simplest and best-known equation of state for substances in the gas phase is the ideal-gas equation of state.
•  It can predict P-v-T with simpler calculation and accurately within some properly selected region (Real gases behave as an ideal gas at low P, high T)

Ideal gas equation of state


Gas constants of different substances