PHASE DEFINITION

WHAT IS PHASE ?

The phases of a system are parts of it which are separated by a distinct boundary,such as solid,liquid and gas

SYSTEM AND PHASE

SYSTEM	PHASE	DESCRIPTION
Mixture of gases	1	Gases are well mixed . we cannot see the boundary between the gases.
Two liquids Do not mix (oil + water)	2	We can see the boundary between the two liquids.
Two liquids well mixed (alcohol + water)	1	We cannot see the boundary of the solution.

EXAMPLE :

             HOW MANY PHASE ??

TWO PHASE                                                             

• solid phase : ice                                                            
• liquid phase: water  

TWO PHASE

• liquid phase : water
• gas phase : vapour

ANOMALOUS BEHAVIOR OF H2O

• The phase diagram for water is not typical.
• Has negative slope
• The melting temperature decreases with pressure
• This is because ice is less dense than water , while most solids are dencer than their liquids.

~ DEFINITION OF TRIPLE POINT ~
        
          Is the temperature and pressure at which the three phases; solid , liquid and gas are in equilibrium.




~DEFINITION OF CRITICAL POINT ~

       Is the temperature and pressure at which there is no boundry between the liquid phase and gas phase.