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NCERT solutions Science Class 9 chapter 2 Is Matter around us Pure

Chapters

NCERT Science Class 9

Science Textbook for Class 9

Chapter 2 - Is Matter around us Pure

Page 15

What is meant by a substance?

Q 1 | Page 15

Page 24

How will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than 25°C), which are miscible with each other?

Q 1 | Page 24

Name the technique to separate butter from curd.

Q 2.1 | Page 24

Name the technique to separate salt from sea-water.

Q 2.2 | Page 24

Name the technique to separate camphor from salt

Q 2.3 | Page 24

What type of mixtures is separated by the technique of crystallization?

Q 3 | Page 24

Page 24

Classify the following as chemical or physical changes : Cutting of trees

Q 1.1 | Page 24

Classify the following as chemical or physical changes: Melting of butter in a pan

Q 1.2 | Page 24

Classify the following as chemical or physical changes:- Rusting of almirah

Q 1.3 | Page 24

Classify the following as chemical or physical changes:- Boiling of water to form steam

Q 1.4 | Page 24

Classify the following as chemical or physical changes:-

Passing of electric current through water, and water breaking down into hydrogen and oxygen gas

Q 1.5 | Page 24

Classify the following as chemical or physical changes:- Dissolving common salt in water

Q 1.6 | Page 24

Classify the following as chemical or physical changes:- Making a fruit salad with raw fruits

Q 1.7 | Page 24

Classify the following as chemical or physical changes:-Burning of paper and wood

Q 1.8 | Page 24

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

Q 2 | Page 24

Pages 28 - 30

Which separation techniques will you apply for the separation of the Sodium chloride from its solution in water.

Q 1.1 | Page 28

Which separation techniques will you apply for the separation of the Ammonium chloride from a mixture containing sodium chloride and ammonium chloride.

Q 1.2 | Page 28

Which separation techniques will you apply for the separation of the Small pieces of metal in the engine oil of a car.

Q 1.3 | Page 28

Which separation techniques will you apply for the separation of the Different pigments from an extract of flower petals.

Q 1.4 | Page 28

Which separation techniques will you apply for the separation of the Oil from water.

Q 1.5 | Page 28

Which separation techniques will you apply for the separation of the Tea leaves from tea.

Q 1.6 | Page 28

Which separation techniques will you apply for the separation of the Fine mud particles suspended in water.

Q 1.7 | Page 28

Write the steps you would use for making tea. Use the words: solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

Q 2 | Page 28

Pragya tested the solubility of three different substances at different temperatures and collected the data as given below( results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).

Substance dissolved Temperature in K
283 293 313 333 353
Potassium nitrate 21 32 62 106 167
Sodium chloride 36 36 36 37 37
Potassium chloride 35 35 40 46 54
Ammonium chloride 24 37 41 55 66

(a)  What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?

(b)  Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.

(c)  Find the solubility of each salt at 293 K. What salt has the highest solubility at this temperature?

(d)  What is the effect of change of temperature on the solubility of a salt?

Q 3 | Page 28

Explain the term Pure substance by giving examples.

Q 4.2 | Page 29

Explain the term Colloid by giving examples.

Q 4.3 | Page 29

How would you confirm that a colourless liquid given to you is pure water?

Q 6 | Page 29

Identify the solutions among the following mixtures:-

(a) Soil

(b) Sea water

(c) Air

(d) Coal

(e) Soda water

Q 8 | Page 29

Which of the following will show the “Tyndall effect”?

(a) Salt solution

(b) Milk

(c) Copper sulphate solution

(d) Starch solution

Q 9 | Page 29

Which of the following are chemical changes?

(a) Growth of a plant

(b) Rusting of iron

(c) Mixing of iron fillings and sand

(d) Cooking of food

(e) Digestion of food

(f) Freezing of water

(g) Burning of candle

Q 11 | Page 30

NCERT Science Class 9

Science Textbook for Class 9
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