HARD
Earn 100

Consider the following process and think about the reaction taking place during the occurrence of such process:

Milk is converted into curd.

  • What changes do you notice?
  • Is it a physical or chemical change?
  • Is it a temporary or a permanent change?

Important Questions on Physical and Chemical Changes

EASY
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
What is corrosion? 
HARD
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
Why do we apply paint on iron articles?
MEDIUM
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
_____is a permanent change and it cannot be reversed.
HARD
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change — A) then it burns (Change — B). The following statements pertain to these changes. Choose the correct one.
(i) Process — A is a chemical change.
(ii) Process — B is a chemical change.
(iii) Both processes A and B are chemical changes.
(iv) None of these processes is a chemical change.
EASY
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
Chemical changes are
MEDIUM
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
  Explain why, rusting of an iron objects are faster in coastal areas than in deserts?
HARD
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
Explain why rusting of iron objects is faster in coastal areas than in deserts.
HARD
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
Seed germination is an example of
MEDIUM
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
Why is germination of a seed a chemical change?
EASY
Science>Chemistry>Physical and Chemical Changes>Chemical Changes

What type of change is curdling of milk?

MEDIUM
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
Anaerobic bacteria digest animal waste and produce biogas (Change — A). The biogas is then burnt as fuel (Change — B). The following statements pertain to these changes. Choose the correct one.
(i) Process — A is a chemical change.
(ii) Process — B is a chemical change.
(iii) Both processes A and B are chemical changes.
(iv) None of these processes is a chemical change.
EASY
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
 A change in which a new substance is formed is a _____ change.
MEDIUM
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
It protects us from harmful ultraviolet rays of the sun.
MEDIUM
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
How would you show that setting of curd is a chemical change?
MEDIUM
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
_____ is a chemical change.
EASY
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
What does chemical change mean?
EASY
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
Changes can sometimes result in new substances.
EASY
Science>Chemistry>Physical and Chemical Changes>Chemical Changes

Give reasons: Burning of paper is a chemical change.

MEDIUM
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
Why are iron objects usually painted?
MEDIUM
Science>Chemistry>Physical and Chemical Changes>Chemical Changes
 When a whisked egg is heated, it scrambles. Identify it is a physical or chemical change.