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Class 7
Science
Physical and Chemical Changes
classify the changes involved in the following pro...

Question:
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food

Answer:

(a) Photosynthesis - Chemical change
Those changes in which new substances are formed, are called chemical changes. Photosynthesis is a chemical change because chemical reaction occur in it which is completed in the presence of sunlight.

(b) Dissolving sugar in water - Physical change
The physical changes are temporary changes which can be easily reversed to form the original substances. Physical changes are those changes which can be easily reversed by physical methods: evaporization and condensation.

(d) Melting of wax - Physical change

(e) Beating aluminium to make aluminium foil - Physical change
(f) Digestion of food - Chemical change

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Question:
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food

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Question: Classify the changes involved in the following processes as physical or chemical changes: (a) Photosynthesis (b) Dissolving sugar in water (c) Burning of coal (d) Melting of wax (e) Beating aluminium to make aluminium foil (f ) Digestion of food

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Question:
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food