Explain how painting of an iron gate prevents it from rusting.

Important Questions on Physical and Chemical Changes

HARD

7th Jammu and Kashmir Board

IMPORTANT

SCIENCE A TEXTBOOK FOR CLASS 7>Chapter 6 - Physical and Chemical Changes>EXERCISES>Q 10

Explain why rusting of iron objects is faster in coastal areas than in deserts.

HARD

7th Jammu and Kashmir Board

IMPORTANT

SCIENCE A TEXTBOOK FOR CLASS 7>Chapter 6 - Physical and Chemical Changes>EXERCISES>Q 11

The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change — A) then it burns (Change — B). The following statements pertain to these changes. Choose the correct one.
(i) Process — A is a chemical change.
(ii) Process — B is a chemical change.
(iii) Both processes A and B are chemical changes.
(iv) None of these processes is a chemical change.

MEDIUM

7th Jammu and Kashmir Board

IMPORTANT

SCIENCE A TEXTBOOK FOR CLASS 7>Chapter 6 - Physical and Chemical Changes>EXERCISES>Q 12

Anaerobic bacteria digest animal waste and produce biogas (Change — A). The biogas is then burnt as fuel (Change — B). The following statements pertain to these changes. Choose the correct one.
(i) Process — A is a chemical change.
(ii) Process — B is a chemical change.
(iii) Both processes A and B are chemical changes.
(iv) None of these processes is a chemical change.

EASY

7th Jammu and Kashmir Board

IMPORTANT

SCIENCE A TEXTBOOK FOR CLASS 7>Chapter 6 - Physical and Chemical Changes>EXERCISES>Q 13

Rust is-

EASY

7th Jammu and Kashmir Board

IMPORTANT

SCIENCE A TEXTBOOK FOR CLASS 7>Chapter 6 - Physical and Chemical Changes>EXERCISES>Q 14

Which of the following is not a physical change?