Vaishnavi Iyer Roll no:15

5th April 2016
Write the properties of particles:

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

6th April 2016

Question:

Why the solids have definite shape?

Answer:

The shapes in between the constituent particles and kinetic energy of the particles are minimum  and arrangements  of particles is most ordered in case of solids. Thus the solids have definite shape.

7 April 2016

GIVE REASONS

1) Why the table is hard?

     The solids like table are hard because the space between the constituent particles are minimum and are tightly packed with each other , and the intermolecular force of attraction is high in case of solids .

2)  Why the diver is able to cut water ?

       The intermolecular force of attraction is less in case of water and it has compressibility. Thus the diver able to cut the water.

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

      When the food is cooked the particles of the food are release and accumulate into the air by the process called diffusion. When the air traveles with the gases it enters into our nose. By this way we can able to smell the sizzling food.

12 April 2016

1) What is latent heat of fusion ?
     The amount heat energy  that is required  to change      1kg of solid intI liquid  at atmospheric pressure at its melting point is known as the latent heat of fusion .
2) What is latent heat of vaporisation ?
    Particles in the steam, that is water vapour at 373K (100°c)  have more energy than water at the same temperature.This is because particles in steam have absorbed  extra energy in the form of heat of vaporisation.

 13 April 2016
1) Name the factors affecting evaporation

•  Temperature - the rate of evaporation is directly proportional to the rise in temperature. If the surface area is increased , the rate of evaporation increases
•  Surface area - if the surface area is increased, the rate of evaporation increases
• Humidity -  humidity is the amount of water vapour present in air. If the amount of water in air is already high , the rate of evaporation decreases.
• Wind speed -  with the increase in wind speed, the particles of water vapour move away with the wind vapour in the surrounding.    

  Chapter2 THE        FUNDAMENTAL      UNIT OF LIFE

            

  21 April 2016

 

1) Why does the water come out from the cucumber when we add salt in it?

    Osmosis is the passage of water from the high water concentration  to low water concentration .In the case of  cucumber the cell of the cucumber contains more water than salt . Thus to maintain the concentration the water come out from the cucumber when the salt is added. 

 

   24 April 2016

1) What is diffusion and osmosis?

       Diffusion :   It is the process of movement  of particles from their higher concentration to their lower concentration .

For example : exange of gases by stomata.

  Osmosis: It is the process of movement of molecules from their higher concentration to their lower concentration in presence of semi permeable membrane.

For example: The movement of water from in and out of the cell takes place by the process of osmosis.