MEDIUM
7th CBSE
IMPORTANT
Earn 100

Why are the tools and machine parts made of iron smeared with grease or oil?

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 14
Explain how, painting of an iron gate prevents it from rusting. 
MEDIUM
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 15
  Explain why, rusting of an iron objects are faster in coastal areas than in deserts?
HARD
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 16
What is meant by galvanisation? Why is it done?
MEDIUM
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 17
Give two methods of preventing the rusting of iron.
MEDIUM
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 18
What is stainless steel? How is stainless steel made? State an important property of stainless steel.
MEDIUM
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 19
State three differences between a physical change and a chemical change.
HARD
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 20
Write a word equation to represent the process of rusting of iron. Also write the chemical symbols and formulae of all the substances involved.
MEDIUM
7th CBSE
IMPORTANT
AWARENESS SCIENCE for Seventh Class>Chapter 6 - Physical and Chemical Changes>Short Answer Type Questions>Q 21
Explain why, explosion of a firework (such as cracker) is said to be a chemical change.