MEDIUM
7th CBSE
IMPORTANT
Earn 100

What are the conditions for rusting?

Important Questions on Physical and Chemical Changes

HARD
7th CBSE
IMPORTANT
Frank Everyday Science>Chapter 6 - Physical and Chemical Changes>Let's revise>Q B
What is crystallisation and in what way is this process useful to us?
HARD
7th CBSE
IMPORTANT
Frank Everyday Science>Chapter 6 - Physical and Chemical Changes>Let's revise>Q B
Why do ornaments of gold and silver look dull after using them for some time?
HARD
7th CBSE
IMPORTANT
Frank Everyday Science>Chapter 6 - Physical and Chemical Changes>Let's revise>Q B
What do you understand by corrosion of metals?
MEDIUM
7th CBSE
IMPORTANT
Frank Everyday Science>Chapter 6 - Physical and Chemical Changes>Let's revise>Q B

What is tinning?

MEDIUM
7th CBSE
IMPORTANT
Frank Everyday Science>Chapter 6 - Physical and Chemical Changes>Let's revise>Q C
Explain how burning of a paper is different from tearing it.
HARD
7th CBSE
IMPORTANT
Frank Everyday Science>Chapter 6 - Physical and Chemical Changes>Let's revise>Q C
How will you prepare crystals of alum? Explain.
MEDIUM
7th CBSE
IMPORTANT
Frank Everyday Science>Chapter 6 - Physical and Chemical Changes>Let's revise>Q C

Explain four methods by which rusting can be prevented

MEDIUM
7th CBSE
IMPORTANT
Frank Everyday Science>Chapter 6 - Physical and Chemical Changes>Let's revise>Q C

Why are burning of wood and cutting of wood into small pieces considered as two different types of changes?