This document discusses properties of pure substances and provides three homework problems. It defines latent heat of vaporization and discusses how superheated steam behaves like an ideal gas obeying Charles' Law. The first problem asks to calculate the internal energy of wet steam at a dryness fraction of 0.9 under constant pressure. The second problem asks to explain Van der Waals' equation, Clausius equation, and Dieterici equation. References for further reading on thermodynamics are also provided.

1. Properties of Pure Substances
S.Gunabalan
Associate Professor
Mechanical Engineering Department
Bharathiyar College of Engineering & Technology
Karaikal - 609 609.
e-Mail : gunabalans@yahoo.com

2. Properties of Pure Substances
fg – latent heat of
vaporization
f – Fluid (Saturated liquid)
g – gas (saturated vapour- steam)

3. Problem-2

4. Given data:

5. super heated steam behave like a
perfect gas - obey Charles law,
(p = Constant )
Constant pressure process
X = 0.9

6. a) Internal energy of the Wet steam at dryness
fraction x = 0.9 super heated steam behave like a perfect
gas - obey Charles law,
(p = Constant )
Constant pressure process
X = 0.9

7. Problem – 3 – Home Work
• Explain the following
a) Van der wall`s equation
b) Clausius equation
c) Dieterici Equation

8. 2- marks

9. Reference
• Rajput, R. K. 2010. Engineering thermodynamics. Jones and Bartlett
Publishers, Sudbury, Mass.
• Nag, P. K. 2002. Basic and applied thermodynamics. Tata McGraw-Hill, New
Delhi.