HARD
7th CBSE
IMPORTANT
Earn 100

Describe physical change with the help of examples.

Important Questions on Physical and Chemical Changes

MEDIUM
7th CBSE
IMPORTANT
Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Chapter Review>Q 2
What are the indications of a chemical reaction taking place?
HARD
7th CBSE
IMPORTANT
Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Chapter Review>Q 3
Addition of water to salt or sand is a physical change whereas to cement is a chemical change. Justify the statement.
MEDIUM
7th CBSE
IMPORTANT
Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Chapter Review>Q 4
Explain an activity to show a change in colour during a chemical reaction. 
MEDIUM
7th CBSE
IMPORTANT
Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Chapter Review>Q 5
When chuna (lime) is added to water, heat is evolved. It is a chemical reaction. Explain.
MEDIUM
7th CBSE
IMPORTANT
Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Chapter Review>Q 6
Write the word equation and symbolic chemical equations for the burning of coal.
MEDIUM
7th CBSE
IMPORTANT
Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Chapter Review>Q 6
Why is rusting considered to be a chemical change?
MEDIUM
7th CBSE
IMPORTANT
Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Time to Think>Q 1
Certain physical changes cannot be reversed by simple physical means. For example, if a page of paper is torn into pieces, you cannot make the same page using the pieces by a simple physical means. Can we call it an irreversible physical change? Can you give a few more such examples.
MEDIUM
7th CBSE
IMPORTANT
Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Time to Think>Q 2
Why is carbon dioxide gas formed when a piece of paper or wood is burnt? Can you explain it with the help of a word equation?