Demo: Bouncing putty

 BOUNCING PUTTY AND NON-BOUNCING SUPERBALL

PURPOSE: Show unusual collisions.


DESCRIPTION: A super ball dropped into a container of sand will not bounce. Conversely, a ball of putty dropped onto a foam rubber pad will bounce nicely.

Class VII (ICSE Board) Subject (Chemistry)

Pracice Questions:

1.      Which of the following is physical change and which is physical change?

(i)                  Melting of wax.

(ii)                Boiling apple

(iii)               Cutting banana

(iv)              Burning paper

(v)                Freezing ice

2.     Write chemical formula of baking powder and lime water

3.     Explain the process of crystallization.

4.     What are CFC’s.

5.     Name the acids present in the following substance.

(i)                  Tamarind

(ii)                Curd

(iii)               Spinach

(iv)              Vinegar

6.     What is indicator?

7.     Give example of homogenous and heterogeneous mixure.

8.     Write symbols of the following elements.

(i)                  Iron

(ii)                Lead

(iii)               Sodium

(iv)              Tungsten

(v)                Mercury

9.     Write chemical formula of Magnesium nitrate, calcium hydroxide and calcium phosphate.

10.  What are isotopes and isobars? Explain giving examples.

11.  What is smog?

12.  What is activity series?

13.  Write uses of aluminium.

14.  What is the mass number of fluorine, sodium, copper and chlorine?

15.  Why do atoms combine? Explain the formation of sodium chloride and ammonia?

16.  What are inert gases write short note.

17.  Write balanced chemical equation for the combustion of ethyl alcohol.

18.  Write balanced chemical equation for the reaction of sulphuric acid with copper to form copper sulphate, water and sulphur dioxide.

19.  What is Ore? Give example.

20.  Write chemical formula of Plaster of Paris. Write it’s uses.