Respiration is a kind of chemical change. How?

Important Questions on Physical and Chemical Changes

EASY

7th CBSE

IMPORTANT

Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Chapter Review>Q 5

What are the methods to prevent rusting of iron articles?

HARD

7th CBSE

IMPORTANT

Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Chapter Review>Q 6

Why does soaking cut vegetables in water prevent their browning?

HARD

7th CBSE

IMPORTANT

Galaxy Science in Everyday Life>Chapter 6 - Physical and Chemical Changes>Chapter Review>Q 1

Describe physical change with the help of examples.

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.