Class 9 Science - Chapter Is Matter Around Us Pure NCERT Solutions | What is meant by a pure substance?

How are sol, solution and suspension different from each other?

Name the technique to separate

(i) butter from curd,
(ii) salt from sea-water,
(iii) camphor from salt.

Differentiate between homogeneous and heterogeneous mixtures with examples.

Identify the solutions among the following mixtures.

(a) Soil
(b) Sea water
(c) Air
(d) Coal
(e) Soda water.

Explain the following giving examples.

(a) saturated solution
(b) pure substance
(c) colloid
(d) suspension

List the points of differences between homogeneous and heterogeneous mixtures.

Classify the following into elements, compounds and mixtures.

(a) Sodium
(b) Soil
(c) Sugar solution
(d) Silver
(e) Calcium carbonate
(f) Tin
(g) Silicon
(h) Coal
(i) Air
(j) Soap
(k) Methane
(l) Carbon dioxide
(m) Blood

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

Which of the following will show “Tyndall effect”?

(a) Salt solution
(b) Milk
(c) Copper sulphate solution
(d) Starch solution.

Which of the following materials fall in the category of a “pure substance”?

(a) Ice
(b) Milk
(c) Iron
(d) Hydrochloric acid
(e) Calcium oxide
(f) Mercury
(g) Brick
(h) Wood
(i) Air.

Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?

State the universal law of gravitation.

Which of the following are matter?

Chair, air, love, smell, hate, almonds, thought, cold, cold-drink, smell of perfume.

A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?

How does the sound produced by a vibrating object in a medium reach your ear?

In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium observations are in agreement with the law of conservation of mass.

sodium carbonate + ethanoic acid → sodium ethanoate + carbon dioxide + water

What are canal rays?

State any two conditions essential for good health.

How is our atmosphere different from the atmospheres on Venus and Mars?

Who discovered cells, and how?

For the symbol H,D and T tabulate three sub-atomic particles found in each of them.

What is loudness of sound? What factors does it depend on?

A stone of 1 kg is thrown with a velocity of 20 m s^-1 across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?

Why is the cell called the structural and functional unit of life?

An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?

The frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute?

A train is travelling at a speed of 90 km h^-1. Brakes are applied so as to produce a uniform acceleration of – 0.5 m s^-2. Find how far the train will go before it is brought to rest.

Explain, why is it difficult for a fireman to hold a hose, which ejects large amounts of water at a high velocity.

Write the electronic configuration of any one pair of isotopes and isobars.

What are the differences between broilers and layers and in their management?