NCERT · Class 9 · Science

Chapter 2: Is Matter Around Us Pure?

Practice each question, then open the answer or worked solution.

Exercise-2.4

Textbook page 24 · 2 questions

Q1Written answer

Classify the following as physical or chemical changes:

Cutting of trees
Melting of butter in a pan
Rusting of almirah
Boiling of water to form steam
Passing of electric current through water and water breaking into hydrogen and oxygen gases.
Dissolving common salt in water
Making a fruit salad with raw fruits, and
Burning of paper and wood

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Worked solution

The following is the classification into physical and chemical change:

Physical change	Chemical change
Cutting the trees Boiling of water to form steam Melting of butter in a pan Making a fruit salad with raw fruits Dissolving common salt in water	Rusting of almirah Passing of electric current through water, and water breaking into hydrogen and oxygen gases Burning of paper and wood

Q2Written answer

Try segregating the things around you as pure substances and mixtures.

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Worked solution

Listed below are the classifications based on pure substances and mixtures: