Page 24 - DJJ20063- Thermodynamics 1

DJJ20063- Thermodynamics 1

Liquid Phase

In the liquid phase, the molecules are;

(a) closely bound, therefore also relatively dense and unable to expand to fill a

space; but
(b) they are no longer rigidly structured so much so that they are free to move

within a fixed volume. An example is a pure liquid state.

Steam Phase
In the steam phase, the molecules;

(a) virtually do not attract each other. The distance between the molecules are not

as close as those in the solid and liquid phases;
(b) are not arranged in a fixed pattern. There is neither a fixed volume nor a fixed

shape for steam.

The three phases described above are illustrated in Fig. 2.0 below. The following are

discovered:
(a) the positions of the molecules are relatively fixed in a solid phase;

(b) chunks of molecules float about each other in the liquid phase; and

(c) the molecules move about at random in the steam phase.

(a) (c)
(b)
rd
Source: Thermodynamics: An Engineering Approach, 3 Ed by Cengel and Boles
Figure 2.0 The arrangement of atoms in different phases

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