Question

Classify the following as physical or chemical changes (i) Cooking of food
(ii) Boiling of water
(iii) Cutting of trees
(iv) Dissolving salt in water
(v) Digestion of food
(vi) Melting of ice

Answer 1

Answer:

1. Chemical change

2. Physical change

3. Physical change

4. Physical change

5. Chemical change

6. Physical change

Answer 2

Steam is Transformation from Liquid to Gas

Explanation:

• Rusting of Iron is a Chemical Process, Almirah's go through rusting. Chemical changes are rusting.
• So cutting of tress is a physical process but not chemical.
• Melting of Butter is a phase change from solid to liquid, so that can be called as a chemical process.
• As above, mentioned that rusting of iron is a chemical process.
• On passing electric current through water, it gets broken up into Oxygen & hydrogen, so its a chemical process.  
• Common salt dissolves in water, making the fruit salads tasty as per taste buds due to no change chemically but physical changes occur.
• As compared the boiling of water & melting of butter are desired are changes leading to formation of steam & butter respectively, that means change is there physically, with no change chemically.
• Burning of wood is a chemical process as there is formation of hydrogen & oxygen gases.