1. Properties of pure substances Flashcards
In single phase, how are properties expressed?
As a function of two independent properties: P(v,T), v(P,T), T(P,v). Can also be included: h, s…
In two phase equilibrium, P and T are no longer independent. Which properties are still independent?
(v,T) and (v,P); can also be included h, s, x…
Isobaric heating of water: expression of heat exchanged?
[Q_p = ∆H_p] or [q_p = ∆h_p]
Tv diagram type and shape of lines?
Has isobaric lines which are upward sloping.
P-v diagram
Has isothermal lines which are downward sloping.
P-v diagram type and shape of lines?
Has isothermal lines which are downward sloping.
What is a saturated liquid?
Liquid at saturation temperature or pressure.
What is saturated liquid-vapor equilibrium?
Mixture of liquid and vapor at saturation temperature or pressure.
What is a saturated vapor?
Vapor at saturation temperature or pressure.
What is a reheated vapor?
Vapor at temperature or pressure higher than saturation temperature or pressure.
Also, vapor with specific volume/enthalpy/entropy higher than specific vapor volume/enthalpy/entropy.
What is saturation temperature?
Temperature at which a pure substance changes phase at constant pressure.
What is saturation pressure?
pressure at which a pure substance changes phase at constant temperature.
P-T diagram type and shape of lines?
Melting, vaporization and sublimation lines converging at triple point, they form like a fork shape.
Quality expression:
x = m(vapor) / m(total)
It defines the fraction of vapor we have in a liquid-vapor equilibrium.
Also, x = (v - v_l) / (v_v - v_l)
For saturated liquid, quality is…
x = 0
