STD-6, CHAPTER-3: NATURE OF MATTER, EXERCISE QUESTION ANSWER

A.     FILL IN THE BLANKS.

1.      The Process of grouping objects with similar properties is called ______.

Ans: classification

2.      Anything that occupies _____ and has _______ is called matter.

Ans: space, mass

3.      In the ________ state of matter, the constituent particles have very little hold on one another.

Ans: gaseous

4.      Light does not pass through a blackboard as it is an ______ object.

Ans: opaque

5.      Smell of a perfume reaches us by the process of _______.

Ans: Diffusion

B.      WRITE TRUE OR FALSE FOR THE FOLLOWING STATEMENTS.

 

1.      Air is a man-made material.                                                                                             False

2.      A thin polythene sheet is transparent.                                                                          True

3.      Pebbles float on water.                                                                                                     False

4.      Diffusion is the mixing of the particles of two materials, on their own.                True

5.      Oxygen gas is slightly soluble in water.                                                                         True

 

C.      TICK THE CORRECT OPTION.

1.      The state/states of matter, that have both a fixed shape and a definite volume, is/are –

(a)   Liquids and solids                                      (b)  gas and liquids

(c)    Solids only                                                   (d) liquids only.

      Ans: Solids only

2.      Your book is made up of matter, because it-

(a)   has mass       

(b)   occupies space         

(c)    occupies space and has some mass       

(d)   does not float on water

      Ans: occupies space and has some mass

3.      Which of the following is an opaque material?

(a)   A piece of wood                  

(b)   A plane, thin sheet of glass      

(c)    Pure air          

(d)   Water in a clear glass container

      Ans: a piece of wood

4.      In which of the following cases would diffusion be the fastest?

(a)   Gas in another gas                                      (b)  liquid in another liquid

(c)    A solid in a liquid                                         (d) a gas in a liquid

      Ans: gas in another gas

5.      Which of the following is insoluble in water?

(a)   Mustard oil                                      (b)  sugar

(c)    Carbon dioxide                               (d) common salt

      Ans: Mustard oil

D.     ANSWER THE FOLLOWING QUESTIONS IN BRIEF.

1.      Define the following:

(a)   Natural materials

(b)   Transparent materials

Ans: (a) Natural materials: Materials which occur naturally are called as natural materials.

(b) Transparent materials:  Materials that allow light to pass through them, are called transparent materials.

2.      Name any three materials that are, (i) transparent (ii) opaque in nature.

Ans: (i) Three transparent materials are, air, clean water, glass

(ii) Three opaque materials are, wood, wall, metal

3.      Which state of matter (i) can (ii) cannot easily change its shape and volume? Why?

Ans: (i) Gaseous state of matter can easily change its shape and volume because in gases, the particles have very little hold on each other. Therefore, these particles can move far apart from each other.

(ii) Solid state of matter cannot easily change its shape and volume because in solids, the particles are very tightly packed with each other and cannot move.

4.      Why do materials diffuse into each other?

Ans: Materials diffuse into each other due to the free movement of their particles.

5.      Define the term ‘solubility’. How does it change on increasing the temperature of water?

Ans: (i) The maximum amount of a substance, that can be dissolved in a given volume of water is called the solubility of that substance in water.

(ii) Solubility of a solid substance increases on increasing the temperature of water. Solubility of a gaseous substance decreases on increasing the temperature of water.

6.      Name three materials that are (i) soluble (ii) insoluble in water.

Ans: (i) Three soluble materials in water are, sugar, common salt, vinegar.

(ii) Three insoluble materials in water are, wood, mustard oil, helium.

E.      ANSWER THE FOLLOWING QUESTIONS.

1.      Why do solids have a fixed shape and a definite volume?

Ans: In solids, the particles hold each other very tightly. So they are very closely packed with each other and thus cannot move. Hence, solids have a fixed shape and a definite volume.

2.      Briefly describe an activity to show that pure water is a transparent liquid.

Ans: Materials Required

(i) a glass tubmler

(ii) pure water

Procedure

Take an empty glass tumbler. Fill it with pure water. Put a coin inside the tumbler and look into the tumbler.

Observation

We can see the coin in the water filled tumbler.

The above activity shows that pure water is a transparent liquid.

3.      Describe an activity to show that a solid can diffuse slowly into a liquid.

Ans: Materials required

(i) clean water

(ii) gas jar

(iii) crystals of potassium permanganate

Procedure

Take some clean water in a gas jar. Drop a few crystals of potassium permanganate in water.

Observation

We will see that pink colour spread slowly in water.

The above activity shows that a solid can diffuse slowly into a liquid.

4.      What is a ‘saturated solution’? How can one prepare a saturated solution of common salt in water?

Ans: (i) A solution which cannot dissolve more amount of a given substance at a given temperature is called a saturated solution.

(ii) ACTIVITY

Materials required

(a) a glass tumbler

(b) common salt

(c) Water

(d) a tea spoon

Procedure

Take a glass tumbler half filled with water. Add half teaspoon of common salt in it and stir well. Keep on adding common salt in half teaspoon amounts and stir well after every addition.

Observation

After adding a particular amount, we will observe that common salt is no more dissolving in the given volume of water.

By doing this above activity, we can prepare a saturated solution of common salt in water.

5.      Suggest one activity to show the effect of temperature on the solubility of a solid in water.

Ans: Materials Required

(i) Two glass tumblers

(ii) Water

(iii) Sugar (solid)

Procedure

Take equal volume of water in two separate glass tumblers. Heat the water in one of the tumblers. Now, add equal amounts of sugar in two tumblers and stir. Keep on adding measured amounts of sugar in two tumblers till it stops dissolving.

Observation

It will be observed that the amount of sugar dissolved in hot water is more.

STD-6, CHAPTER 3: NATURE OF MATTER, EXTRA QUESTION ANSWERS

1.      Define ‘classification’.

Ans: The process of grouping objects with similar properties is called classification.

2.      What is the need of classification?

(OR) Why do we need to classify things?

Ans: Classification is needed to make the study of materials, and their properties easier. Thus we can distinguish one thing from the other.

3.      How materials are classified on the basis of their occurrence?

Ans:  On the basis of their occurrence, materials are classified as, (i) Natural Materials

(ii) Man-made or synthetic materials

4.      What are natural materials?

Ans: The materials which occur naturally, are called natural materials.

5.      Give some examples of naturally occurring materials.

Ans: Examples of naturally occurring materials are, wood, water, air, kerosene, wood etc.

6.      What are synthetic materials?

Ans: The materials, which are prepared by man, are called man-made or synthetic materials.

7.      Give some examples of man-made materials (synthetic materials).

Ans: Some examples of man-made materials are, steel plate, plastic bucket, glass tumbler, chair, table etc.

8.      Distinguish between natural and synthetic materials.

Ans:

NATURAL MATERIALS	SYNTHETIC MATERIALS
The materials which occur naturally, are called natural materials.	The materials, which are prepared by man, are called man-made or synthetic materials.
Examples of naturally occurring materials are, wood, water, air, kerosene, wood etc.	Some examples of man-made materials are, steel plate, plastic bucket, glass tumbler, chair, table etc.

 

9.      Find the odd one out of the following group of things.

Milk shake, Lipstick, Clothes, Coal, Paper

Ans: Coal is different from the rest. (as all the things are man-made except Coal. It occurs naturally)

10.  Define the term ‘matter’.

Ans: Anything that occupies space and has mass is called matter.

11.  How can we classify matter?

Ans: Matter can be classified into three groups on the basis of its physical state.

12.   Name the three groups (physical states) of matter.

Ans: The three groups (physical states) of matter are, solid, liquid and gaseous.

13.  Give any five examples of solids.

Ans: Rock, Coal, Wood, Metals, Plastic bucket etc. are solids in their physical state.

14.  Give any five examples of liquids.

Ans: Milk, Water, Vinegar, Honey, Mercury (an element of nature used in thermometer) etc. are liquids in their physical state.

15.  Give any five examples of gases.

Ans: Oxygen, Nitrogen, Helium, Carbon dioxide, Carbon monoxide etc. are gaseous in nature.

16.  All matter is made up of very small _______.

Ans: Particles

17.  How particles are arranged in solids?

Ans: In solids, the particles are very tightly packed with each other.

18.  Give one characteristic feature of solids.

Ans: Solids have a fixed shape and a definite volume.

19.  Why do solids have a fixed shape and a definite volume?

Ans: In solids, the particles hold each other very tightly. So they are very closely packed with each other and thus cannot move. Hence, solids have a fixed shape and a definite volume.

20.  Why solids cannot change their shape and volume easily?

Ans: In solids, particles are closely packed and hold each other very tightly. Hence, solids have a definite shape and volume. It is not so easy for the particles to move apart. Thus, solids cannot change their shape and volume easily.

21.  How particles are arranged in liquids?

Ans: In liquids, the particles are less tightly packed.

22.  Give one characteristic feature of liquids.

Ans: Liquids have a definite volume but do not have a fixed shape.

23.  Why do liquids take up the shape of the container in which they are kept?

(OR) Why can liquids change their shape easily?

Ans:  In liquids, particles are less tightly packed. The particles have some space between them. So they can move a little. Hence, their shape is not fixed and they take up the shape of the container in which they are kept.

24.  Give one characteristic feature of gases.

Ans: Gases neither have a definite shape nor a definite volume.

25.   Why can gases change their shape easily?

Ans: In gases, the particles have very little hold on each other. Therefore, they can move far apart from each other. So, they can change their shape easily.

26.  Choose the correct answer.

The states of matter,that have both a fixed shape and definite volume is /are,

(a) Solids and Gases    (b) Gases and liquids   (c) Solids and liquids    (d) only soilds

      Ans: Only Solids

27.  Sketch the particles of three states of matter on the basis of their arrangement.

(OR) Draw the arrangement of particles in three states of matter.

Ans:

           

28.  Differentiate between solids, liquids and gases.

Ans:

SOLIDS	LIQUIDS	GASES
Solids have a fixed shape and a definite volume.	Liquids do not have a definite shape but have a fixed volume.	Gases neither have a fixed shape nor a definite volume.
In solids particles are tightly packed.	In liquids, the particles are less tightly packed.	In gases, the particles are loosely packed.
Solids cannot flow.	Liquids can flow.	Gases can flow in all directions.

 

29.  Why do the three states of matter differ in their properties?

Ans: The three states of matter differ from each other in properties due to differences in the nature of packing of particles in them.

30.  Name some physical properties of matter.

Ans: Some physical properties of matter are, (i) smoothness/roughness (feel), (ii) Lustrous/dull (appearance), (iii) Transparency, (iv) Strength, (v) Dissolution (Solubility), (vi) Tendency to float or sink, (vii) Diffusion etc.

31.  Name two materials which are smooth to touch.

Ans: Marbles and mirror (polished glass surface) are smooth to touch.

32.  Name two materials which feel rough when touched.

Ans: Sandpaper, Rock surface

33.  Name any two materials which have lustre.

Ans: Metals (Gold, silver etc.) and diamond have lustre.

34.  Name any two materials which are dull in appearance.

Ans: Wood, coal are dull in appearance.

35.  What is transparency?

Ans: The property of a material to allow light to pass through it is called transparency.

36.  Define ‘Transparent materials’.

Ans: Materials which allow light to pass through them, are called transparent materials.

   (OR) The materials through which we can see clearly, are called transparent materials.

37.  Give two examples of transparent materials.

Ans: Glass and clean water are the two examples of transparent materials.

38.  Define ‘Opaque materials’.

Ans: Materials which do not allow light to pass through them, are called opaque materials.

   (OR) The materials through which we cannot see at all, are called opaque materials.

39.  Give some examples of opaque materials.

Ans: Wood, Thick plastic sheet, blackboard and wall are some examples of opaque materials.

40.  Which of the following is an opaque material?

(a) Piece of wood     (b) Clean water      (c) Pure air       (d) None of these

Ans: Piece of wood

41.  Differentiate between transparent and opaque materials with one example for each.

Ans:

TRANSPARENT MATERIALS	OPAQUE MATERIALS
Materials which allow light to pass through them, are called transparent materials.	Materials which do not allow light to pass through them, are called opaque materials.
We can see through transparent materials.	We cannot see through opaque materials.
Example, Clean water	Example, Wood

 

42.  Materials which are ______ than water, generally, float over it.

Ans: lighter

43.  Name any two materials that are lighter than water.

(OR) Name any two materials that floats over water.

(OR) Why ice/oils float over water?

Ans: Ice, Oil (vegetable oil) generally lighter than water. So they float over water.

44.  Materials which are ______ than water, generally, sink in it.

Ans: heavier

45.  Name any two materials that are heavier than water.

(OR) Name any two materials that sink in water.

(OR) Why metal balls/pebbles sink in water?

Ans: Balls of Metals (iron, copper etc.), pebbles are generally heavier than water. So they sink in water.

46.  The materials, which do not dissolve in water, either ______ on its surface or _____ to the bottom of the container.

Ans:  The materials, which do not dissolve in water, either float on its surface or sink to the bottom of the container.

47.  Name some solids which sink in water.

Ans: Sand, coins, pebbles, carbon tetra chloride, iron nails, marbles etc. sink in water.

48.  Name some solids which float on water.

Ans: Cork, Butter paper, thermocole, saw dust, float on water.

49.  Name two liquids which float on water.

Ans: Hair oil, mustard oil, float on water.

50.  Name one liquid which sinks in water.

Ans: Carbon tetrachloride

51.  Define ‘Diffusion’.

Ans: The property of mixing of particles, of two materials, on their own, is called diffusion.

52.   Why do materials diffuse into each other?

Ans: Materials diffuse into each other due to the free movement of their particles.

53.  Why do gases diffuse into each other very quickly?

Ans: Gases diffuse very quickly into each other because their particles are in constant motion and they are free to move.

54.  Why do liquids diffuse into each other quite slowly?

Ans: Liquids diffuse into each other quite slowly, because particles in a liquid are not so free to move.

55.  Why don’t solids diffuse with each other?

Ans: Solids do not diffuse into each other because their particles are held tightly and cannot move freely.

56.  Why can solids diffuse into water?

Ans: Solids can diffuse slowly into liquids. This is because particles of liquid are able to move.

57.  When is a substance said to be dissolved?

Ans: When one substance mixes completely with another substance, to give a clear solution, it is said to be dissolved.

58.  Define the term ‘dissolution’.

Ans: The property by which a substance dissolves in another substance, is called dissolution.

59.  Define the term ‘solubility’.

Ans: The maximum amount of a substance, that can be dissolved in a given volume of water is called the solubility of that substance in water.

60.  Define a soluble substance.

Ans: A substance which dissolves in water is said to be soluble in it.

61.  Name some substances which are soluble in water.

Ans: Sugar, salt and lemon juice are all soluble in water.

62.  Define a solution.

Ans: When a substance dissolves completely in any medium, we get a solution.

63.  Define a solute.

Ans: The substance, that gets dissolved in a medium to form a solution, is called a solute.

64.  What is a solvent?

Ans: The medium, in which the substance is dissolved, is called a solvent.

65.  Identify the solute and solvent in a nimboo-pani drink.

Ans: In a nimboo-pani drink, Water is the solvent whereas sugar, salt and lemon juice are all solutes.

66.  Define insoluble substances.

Ans: The substances that do not get dissolved in water are said to be insoluble substances (in water).

67.  Name two substances that are insoluble in water.

Ans: Pebbles, saw dust, chalk powder etc. are insoluble in water.

68.  How does solubility of a solid substance change on increasing the temperature of water?

Ans: Solubility of a solid substance increases on increasing the temperature of water.

69.  Define the term ‘saturated solution’.

Ans: A solution which cannot dissolve more amount of a given substance at a given temperature is called a saturated solution.

70.  Name two liquids which are soluble in water.

Ans: Lemon juice and vinegar are soluble in water.

71.  Name two liquids which are insoluble in water.

Ans: Kerosene and vegetable oils

72.  Name the liquids which forms a layer above water.

Ans: Kerosene, vegetable oils, hair oils etc. form a layer above water.

73.  Name the liquid which forms a layer below water.

Ans: Carbon tetrachloride forms a layer below water.

74.  Name two gases which are soluble in water.

Ans: Carbon dioxide and oxygen

75.  Name the gases which are not soluble in water.

Ans: Nitrogen, helium, ozone, hydrogen

76.  Why do you think oxygen in water is important for the survival of aquatic animals and plants?

Ans: Oxygen gas dissolves in water, i.e. oxygen gas is soluble in water. The plants and animals which live in water use the oxygen dissolved in water for respiration. Thus, oxygen gas dissolved in water is very important for the survival of animals and plants that live in water.

77.  How does solubility of a gaseous substance change on increasing the temperature of water?

Ans: Solubility of a gaseous substance decreases on increasing the temperature of water.