babita sharma (roll no -5)

                           ch-1 matter in our surrounding

• Matter:-anything that mass and occupies space is matter

• Matter:solid ''liquid 'and gases''

                                                             

                    EXERCISES

1. Convert the following temperatures to Celsius scale.

(a) 300 K

 300 K = (300 - 273) °C
= 27 °C

(b) 573 K

 573 K = (573 - 273) °C
= 300 °C

2. Convert the following temperatures to Kelvin scale.

(a) 25°C

25 °C = (25 + 273) K
= 298 K

(b) 373°C

 373 °C = (373 + 273) K
= 646 K

3. Give reason for the following observations.

a) Naphthalene balls dissapear with time as the temperature rises , it gets sublimated                       in gas without leaving any solid .
              
               b) The molecules of perfumes gets mixed in the air molecules which is the least dense                              matter , that is why we get the smell perfume sitting several meters away .

ANSWER  4
      
               -   Oxygen - Water - Sugar

ANSWER 5

               a) Liquid State
                
               b) Solid State

                c)Gaseous State

ANSWER 6
                                  
               a) Water at room temperature has a medium force of attraction so it  is in liquid form .
                b) At room temperature , the inter molecular force  of  solid is so high that its                                            molecules get packed together tightly .
ANSWER 7

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

ANSWER 8
              Steam will cause more serve burns.