NCERT Class VII Science Solutions: Chapter 6-Physical and Chemical Changes Part 1

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Question 1:

Classify the changes involved in the following processes as physical or chemical changes:

  1. Photosynthesis

  2. Dissolving sugar in water

  3. Burning of coal

  4. Melting of wax

  5. Beating Aluminum to make Aluminum foil

  6. Digestion of food

Answer:

Physical Changes:

B. Dissolving sugar in water

D. Melting of wax,

E. Beating Aluminum to make Aluminum foil.

As showing in images is a Dissolving sugar in water, Melting of wax, Beating Aluminium to make Aluminium foil

Dissolving Sugar, Melting Wax, Aluminium Foil

As showing in images is a Dissolving sugar in water, Melting of wax, Beating Aluminium to make Aluminium foil

Chemical Changes:

A. Photosynthesis,

C. Burning of coal,

F. Digestion of food,

As showing in images is a Photosynthesis, Burning of coal, Digestion of food,

Photosynthesis, Burning of Coal, Digestion of Food,

As showing in images is a Photosynthesis, Burning of coal, Digestion of food,

Question 2:

State whether the following statements are true or false. In case a statement is false, write the corrected statement in your notebook.

  1. Cutting a log of wood into pieces is a chemical change. (True/False)

  2. Formation of manure from leaves is a physical change. (True/False)

  3. Iron pipes coated with zinc do not get rusted easily. (True/False)

  4. Iron and rust are the same substances. (True/False)

  5. Condensation of steam is not a chemical change. (True/False)

Answer:

  1. Cutting a log of wood into pieces is a chemical change. (False)

  2. Formation of manure from leaves is a physical change. (False)

  3. Iron pipes coated with zinc do not get rusted easily. (True)

  4. Iron and rust are the same substances. (False)

  5. Condensation of steam is not a chemical change. (True)