Changes Around Us Physical and Chemical Class 7 Fill in the Blanks
hardChanges Around Us Physical and Chemical Class 7 Fill in the Blanks
Changes Around Us Physical and Chemical Class 7 Fill in the Blanks
Question 1.
The brown deposits on Nalini's cycle handle are due to ............, and this is a..........change.
Answer:
rusting, chemical
Question 2.
Folding a handkerchief is a ............change and can be .............
Answer:
physical, reversed
Question 3.
A chemical process in which a substance reacts with oxygen with the evolution of heat is called .............
Answer:
combustion
Question 4.
Nalini observed that the handle of her cycle has got brown deposits. The brown deposits are due to ............, and this is a ............change.
Answer:
rusting, chemical
Changes Around Us Physical and Chemical Class 7 True or False
Question 1.
Rusting of iron is a physical change.
Answer:
False (It is a chemical change.)
Question 2.
Melting of ice is a chemical change.
Answer:
False (It is a physical change.)
Question 3.
The process of making popcorn from corn is a physical change.
Answer:
False (It is a chemical change.)
Question 4.
Boiling water is an example of a physical change.
Answer:
True
Question 5.
The cutting of paper is a chemical change.
Answer:
False (It is a physical change)
Changes Around Us Physical and Chemical Class 7 Match the Following
Question 1.
| Column A | Column B |
| (a) Physical change | (i) Melting of ice |
| (b) Chemical change | (ii) Rusting of iron |
| (c) Reversible change | (iii) Evaporation of water |
| (d) Irreversible change | (iv) Burning of paper |
| (e) No change in substance | (v) Cutting of paper |
Answer:
| Column A | Column B |
| (a) Physical change | (v) Cutting of paper |
| (b) Chemical change | (ii) Rusting of iron |
| (c) Reversible change | (i) Melting of ice |
| (d) Irreversible change | (iv) Burning of paper |
| (e) No change in substance | (iii) Evaporation of water |
Question 2.
| Column A (Processes) | Column B (Type of change) |
| (a) Condensation | (i) Physical change |
| (b) Digestion of food | (ii) Chemical change |
| (c) Freezing | (iii) Reversible change |
| (d) Baking a cake | (iv) Irreversible chemical change |
| (e) Boiling water | (v) Reversible physical change |
Answer:
| Column A (Processes) | Column B (Type of change) |
| (a) Condensation | (i) Physical change |
| (b) Digestion of food | (ii) Chemical change |
| (c) Freezing | (iii) Reversible change |
| (d) Baking a cake | (iv) Irreversible chemical change |
| (e) Boiling water | (v) Reversible physical change |