BHASKAR TIWARI

CHAPTER NO 1

MATTER IN OUR SURROUNDINGS

 DATE 04/April/2016
QUESTION-1

Why do we observe that level of water does not change even after the dissolving of salt in it?

ANSWER

Level of water do not change even after dissolving the salt because there is space between the particles of water and the when we dissolve salt in water the particles of salt gets filled or adjusted in between the particles of water and thus the level of water do not change.

      Molecules of water are present in the glass.
             

      After dissolving the salt in the water the molecules of salt in blue                                                         occupies the space between the molecules of water.

               
     Then the molecules gets randomly distributed in the solution so the 
                                                 water level remain the same

DATE 05/April/2016

PROPERTIES OF PARTICLES

• The particles of matter are very small
• The particles of matter are continuously moving means they have kinetic energy.
• The particles of matter have space between them.

                              DATE 06/April/2016

 Solid has a fixed shape and a definite volume. The molecules in a solid are in fixed positions and are close together. Although the molecules can still vibrate, they cannot move from one part of the solid to another part. the force of attraction is very high in solid that is why it maintains its shape.

                                      



 A molecular structure of a solid matter.

  

DATE 07/April/2016

Q 1- Why table is hard?

ANS- Table is hard because the force of attraction in its molecules are very high and which results in the close packing of molecules and it is very dense.

Q 2- Why diver is able to cut water?

ANS- Diver is able to cut water because the water is less denser and force of attraction is also less which results in the distance of molecules. The molecules are loosely packed.

Q 3- Why the smell of hot sizzling food reaches our nose?

ANS- Smell of hot sizzling food reaches our nose because the in hot temperature the molecules move faster which results in reaching the smell of food to our nose very quickly. 

  DATE 18/April/2016

EXERCISE

Ans 1-

 (a) 298 K

            (b) 646 K

Ans 2- 

 (a) 20*c

  (b) 197*c

Ans 3- 

(a) Naphthalene balls disappear with time as the temperature rises, it gets sublimated in gas without leaving any solid.

  (b) The molecules of perfume gets mixed with air molecules which is the least densest matter , that is why we gets smell of perfume sitting several meters away.

Ans 4-

 Oxygen -------> Water -------> Sugar 

Ans 5-

 (a) Liquid State

           (b) Solid State

    

 (c) Gaseous State

Ans 6-

 (a) (i) At room temperature the force of attraction between the molecules of water is medium that is why it is in liquid form.

                

 (ii) The room temperature (25*c) is higher than freezing point (0*c) which will make it solid and it is less than boiling point (100*c) which will make it gas.

            

(b) (i) At room temperature , the intermolecular force of solid is so high that its molecules gets packed together tightly.

                 

(ii) It has fixed shape and fixed volume.

Ans 7-

 At 273 K or 0*c the ice will give more cooling than water because it can absorb more heat than water due to its latent heat of fusion.

Ans 8-

 Steam will cause more serve burns.

Ans 9-

 

A- Melting 

B- Evaporation

C- Condensation

D- Solidification

E- Sublimation

F- Sublimation