rohit kumar

It is my home work page 
And I do my homework regularly  

  Date : 05/04/2016

                                                             Chapter:1                                                                                   Matter In Our Surrounding 

                                           Properties of particles

 1. The particles of the matter very small. 2. Thee particles of the matter are continuously moving means they have kinetic energy .

 3. The particles of the matter have space between them.Date:07/04/2016                                  Matter In Our Surrounding

Qns1. Why solids have fixed shape?

Ans1. Solids have fixed shape because in solids the atoms are bonded tightly and there is very very less space in between atoms. So they have a definite shape and size.

Date:12/04/2016

                                                   

                                Matter In Our Surrounding

                          

                                         Give Reasons

• Why the table is hard?

Answer:-The table is hard because in the table there are some particles and they are tightly packed .In this the inter molecular force of attraction is very high so they attract with each other. So this is the reason that's why the table is hard.

• Diver is able to cut the water?

Answer:-the particles of matter have space between them. This space is the maximum in the gases and the minimum in liquid. Thus, one cannot cut through a solid easily but a diver is able to cut easily through water in a swimming pool.

• How the smell of hot sizzling food is reached to our nose?

Answer:- when food is cooked, some of the substances in food release gases having the smell of food in them. The particles of these gases move very quickly and mix up with air by diffusion. When the air containing these gases reaches your nose, we get the smell of hot and sizzling food.

Homework- 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

Ans 9-

A- Melting
B- Evaporation
C- Condensation
D- Solidification
E- Sublimation

F- Sublimation