MEDIUM
7th CBSE
IMPORTANT
Earn 100

Explain why, explosion of a firework (such as cracker) is said to be a chemical change.

Important Questions on Physical and Chemical Changes

MEDIUM
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 22
Explain why, melting of ice to form water is said to be a physical change.
MEDIUM
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 23
What is meant by crystallisation? State its one use.
HARD
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 24
Describe how crystals of copper sulphate are prepared.
EASY
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 25
Give example of a chemical change which occurs by the action of heat.
EASY
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 25
Give example of a physical change which occurs by the action of heat.
HARD
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Long Answer Type Questions>Q 26
What is a physical change, and chemical change? Give two examples of physical changes and two examples of chemical changes.
HARD
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Long Answer Type Questions>Q 27
What is meant by the rusting of iron? State two conditions necessary for the rusting of iron to occur. Explain how, rusting damages iron objects.
HARD
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Long Answer Type Questions>Q 28
What happens when an iron nail is kept immersed in copper sulphate solution? Write a word equation for this process. Name the type of change involved.