Physical And chemical change

                     1 . FILL IN THE BLANKS 

1 change is generally reversible .
2 Brownish film on iron object kept in open air is called .
3 Chemical change involves formation of .
4 is formed in burning of magnesium
5 Presence of & are necessary for rusting.
6 water makes the process of rusting fast.
7 Rusting can be prevented by & .
8 Chemical name of baking soda
9 gas turns lime water milky due to the formation of .
10 Physical change involves only change in properties like & .

  1. Define
    1 Rusting
    2 Galvanization
    3 chemical reaction
    4 Crystallization
  2. Define between physical and chemical change
  3. Give reason
    1 It is dangerous to look for long time at burning magnesium
    2 Why magnesium oxide turn litmus paper blue
    3 Stainless steel doesn’t rust .
    4 Rusting of iron object is faster in coastal areas then desert areas
    5 . What happens when :-
    1 Magnesium air is burnt in air
    2 A nail is added to blue colour copper sulphate solutions
    3 Carbon dioxide is passes through lime water
    4 Vinegar is added to baking soda
    5 Lemon juice is added to baking soda
  4. Classify the following as physical and chemical change
    1 explosion of firework
    2 sugar in water
    3 photosynthesis
    4 melting of wax
    5 burning of candle
    6 digestion of food
    7 rusting
    8 burning of coal
    9 tearing of paper
    10 making aluminum foil
  5. Mention changes observed during chemical change other than formation of new substance
  6. Describe how crystals of copper sulphate is formed

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