NCERT-Notes-for-class-9-science-matter-in-our-surroundings/ by knowledge cave part 2......

                            CHAPTER 1

            MATTER IN OUR SURROUNDINGS❤❤

(6) EXPLATION OF CONVERSION FROM LIQUID STATE TO GASEOUS STATE:-

      When we heat any liquid substance,the particles gain energy.As result,their kinetic energy increase and they start vibrating with greater amplitude due to which their intermolecular force decrease,Thus,it gets converted into gaseous state.

(7) CONVERSION FROM GAS TO LIQUID STATE.

Condensation :- It is a change from gaseous state to liquid state to liquid state on cooling. This occurs at a temperature below the boiling of substance.

 LIQUEFACTION POINT.

(8) EXPLANATION OF CONVERSION FROM GASEOUS STATE TO LIQUID STATE ON COOLING:-

Liquefation of gases:- Change of state of substance from gaseous to liquid ,on applying pressure and reducing temperature.

EXPLANATION:- When high pressure is applied on gas,distance between particles decrease particles decreases & particles start attracting each other &gas gets converted into liquid state.

NOTE:- Whenever change in state (phase transition) takes place,mass of matter does not change.

(8) CONVERSION FROM LIQUID STATE TO SOLID STATE.

FREEZING:- It is the change of substance from liquid state on cooling at freezing point.

FREEZING POINT:- It is the temperature at which liquid changes to solid state on cooling.

(9) EXPLANATION OF CONVERSION FROM LIQUID TO SOLID STATE ON THE BASIS OF MOLECULAR STRUCTURE:-

When we cool the Liquid,the kinetic energy of molecules decrease and they start vibrating with lower amplitude. As a result their intermolecular space decrease and intermolecular increase.Finally it gets converted to solid state.

(10) CONVERSION OF SOLID DIRECTLY INTO GASEOUS STATE:-

SUBLIMATION:-It is the change of solid directly to gaseous state,on heating & vapour back to solid,on cooling.

(1) SUBLIME:- A gaseous state, that is formed due to sublimation of solid.

(2) SUBLIMATE:- It is the solid that sublimes.

          for example;- Napthalene Balls.

(11) EVAPORATION :- It is defined as the process of change from liquid tovapour at temperature below boiling point.

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