Lakhmir Singh Manjit Kaur Class 9 Chemistry 1st Chapter “Matter In Our Surroundings” Part- I solution

Lakhmir Singh and Manjit Kaur Chemistry solution: “Matter In Our Surroundings” Part-I Chapter 1. Here you get easy solutions of Lakhmir Singh and Manjit Kaur Chemistry solution Chapter 01 . Here we give Chapter 01 all solution of Class 9. Its help you to complete your homework.

Board – CBSE

Text Book – SCIENCE (Chemistry)

Class – 9

Chapter – 01 (First Part)

Very Short Answer Type Questions:

(1) What are the conditions for ‘something’ to be called matter?

Ans. Must occupy space and have mass.

(2) Name two process which provide the best evidence for the motion of particles I matter.

Ans. Diffusion & Brownian motion.

(3) Which single term is used to describe the mixing of copper sulphate and water kept in a beaker on its own?

Ans. Diffusion.

(4) When sugar is dissolved in water there is no increase in the volume. Which characteristic of matter is illustrated by the observation ?

Ans. Particles of matter have spaces between them.

(5) Even two or three crystals of potassium permanganate can impart colour to a vary large volume of water. Which characteristic of particles of matter is illustrated by this observation.

Ans. Particles of matter is very small.

(6) When an incense stick is lighted in one corner of a room, its fragrance spreads in the whole room quickly. Which characteristic of the particles of matter is illustrated by this observation.

Ans. Particles of matter are constantly moving.

(7) A piece of chalk can be broken into small particles by hammering but a piece of iron can not be broken into small particles by hammering. Which characteristic of the particles of matter is illustrated by these observations?

Ans. Particles of matter attract each other.

(8) What is the scientific name of particles which make up matter?

Ans. Atoms or Molecules.

(9) Name the process by which a drop of ink spreads in a beaker of water.

Ans. Diffusion.

(10) What is the general name of :

(a) rigid form of matter?

(b) fluid forms of matter?

Ans. (a) Solid

(b) Liquid and Gas.

(11) Out of solids, liquids and gases, which one has:

(a) maximum movement of particles?

(b) maximum interparticle attractions?

(c) minimum spaces between particles?

Ans. (a) Gas

(b) Solids

(c) Solids

(12) A substance has a definite volume but no definite shape. State this substance is a solid, a liquid or a gas.

Ans. Liquid.

(13) Name the physical state of matter which can be easily compressed.

Ans. Gas.

(14) A substance has a definite shape as well as a definite volume. Which physical state is represented by this statement?

Ans. Solid.

(15) A substance has neither a fixed shape, nor a fixed volume. State whether it is a solid, a liquid or a gas.

Ans. Gas.

(16) Name two gases which are supplied in compressed form in homes and hospitals.

Ans. Home – LPG; Hospital – Oxygen.

(17) Write the full forms of the following:

(a) LPG – Liquid Petroleum Gas.

(b) CNG – Compact Natural Gas.

(18) Which of the two diffuses faster: a liquid or a gas.

Ans. Gas.

(19) Which of the two diffuses slower: bromine vapour into air or copper sulphate into water?

Ans. Copper Sulphate into water.

(20) State whether the following statement is true or false:

Red brown bromine vapour diffuse into air in a gas jar but the colorless air molecules do not diffuse into bromine vapour.

Ans. False.

(21)  A bottle of perfume was opened in a room . The smell of its vapours spread in the entire room. Name the property of gases which is responsible for the behavior of perfume vapours.

Ans. Diffusion of gases.

(22) If the fish is being fried in a neighboring home, we can smell it sitting in our own home. Name the process which bring the smell to us.

Ans. Diffusion.

(23) Name one property of liquids and gases which tells us that their molecules are moving constantly.

Ans. They can flow easily.

(24) (a) The best evidence that the particles of matter are constantly moving come from the studies of ____ and _______

Ans. Diffusion; Brownian motion.

(b) The smell of perfume gradually spreads across a room due to ______

Ans. Diffusion.

(c) Solid, liquid and gas are the three ______ of matter.

Ans. Stats

(d) At room temperature, the forces of attraction between the particles of solid substances are ______ than those which exist in the gaseous state.

Ans. Higher.

(e) the arrangement of particles is less ordered in the ______ state. However, there is no order in the _____ state

Ans. Liquid; Gas.

Short Answer Type Questions:

(25) State two characteristics of matter demonstrated by:

(a) diffusion

(b) Brownian motion.

Ans. (a) Diffusions:- The movement of different particles among each other on their own, so that they become mixed uniformly, is called diffusion.

(b) Brownian motion:- The zig zag movement of the small particles suspended in a liquid or gas is called Brownian motion.

(26) Name the scientist who studied the movement of pollen grains suspended in water through a microscope. What is this phenomenon known as?

Ans. Robert Brownian.

This phenomenon known as Brownian motion.

(27) When a crystal potassium permanganate is placed in a beaker, its purple color spreads throughout the water. What does this observation tell us about the nature of potassium permanganate and water?

Ans. The observation tell us about the nature of potassium permanganate and water is that

(i) The matter (here potassium permanganate and water) is made up of small particles.

(ii) The particles of matter (here water) have spaces between them.

(28) When a gas Jar containing air is inverted over a gas jar containing bromine vapour, the red brown bromine vapour diffuse into air. Explain how bromine vapour diffuse into air.

Ans. Both air and bromine vapour made of tiny moving particles. The moving particles of bromine vapour and air collide with each other and bounce about in all directions, due to which they get mixed uniformly.

(29) Describe in your own words , what happens to the particles when salt dissolves in water.

Ans. The salt particles goes in the spaces between the water particles and dissolves in water.

(30) Explain why we can easily move our hand in air but to do the same through a plank of wood, we need a karate expert.

Ans. This is because air is a gas whose particles are very far apart and there are very weak forces of attraction between them. Extremely weak forces between particles of air can be overcome easily due to which we can move our hand in air. On the other hand, the particles of a solid plank of wood are very closely packed and there are very strong forces of attraction between the particles of wood. Hence, it needs a huge outside force to overcome the strong inter particle attractions which only a karate expert can apply.

(31) Give one example of the diffusion of a solid in another solid.

Ans. If two metal blocks are bound together tightly and kept undisturbed for a few years , then the particles of one metal are found to have diffused into the other metal.

(32) Explain why the diffusion of a solid in another solid is a very slow process.

Ans. The diffusion in solids is very very slow because the particles in solids do not move from their fixed positions. The particles of a solid only vibrate about their fixed positions. Due to lack appreciable movements in the particles of solids, the diffusion of solids in solids is rare.

(33) Which of the following diffuses fastest and which is slowest?

Solid, Liquid, Gas.

Give reason for your answer.

Ans. Solid – Slowest.

Gas- Fastest.

Solid: Slowest because the particles of solid only vibrate on there fixed position. An even they can not move.

Gas: Fastest because the gas particles moves here and there in all direction and collide with the particles of air present in the surroundings.

(34) Explain the following:

When an incense stick is lighted in the corner of a room, its fragrance spreads quickly in the entire room.

Ans. The fragrance of burning incense stick spreads all around due to the diffusion of its smoke into the air. The particles of gases produced by the burning of incense stick move rapidly in all directions. They collide with the particles of air present in the room, mix with air and reach every part of the room very quickly.

(35) Name the three states of matter. Give one example of each.

Ans. The three states of matter are Solids, Liquid and Gas.

The example of Solids: Sugar.

The example of Liquids: – Milk.

The example of Gas: – Air.

(36) State two characteristics properties of :

(a) a solid

(b) a liquid

(c) a gas.

Ans. (a) Properties of Solids:- (i) Solids have a fixed shape and a fixed volume.

(ii) Solids can not be compressed much.

(b) Properties of Liquids:- (i) Liquid have fixed volume but they have no fixed shape. Liquids take the shape of the vessel in which they are placed.

(ii) Like solids, Liquids can not be compressed much.

(c) Properties of Gases:- (i) Gases have neither a fixed shape nor a fixed volume. Gases acquire the shape and volume of the vessel in which the are kept.

(ii) Gases can be compressed easily.

(37) Why do gases have neither a fixed shape nor a fixed volume?

Ans. A gas does not have fixed shape because the position of its particles are not fixed. A gas does not have fixed volume because the spaces between its particles are not fixed.

(38) How do Solids, Liquids and Gases differ in shape and Volume?

Ans. Solids: Solids are having fixed shape and fixed volume.

Liquids: Liquids are having fixed volume but they do not have fixed shape. Liquids take the shape of container in which they are kept.

Gases:- Gases do not have fixed shape and fixed volume. They take the shape and volume of the container in which they are kept.

(39) Arrange the following substances in increasing order of force of attraction between their particles (keeping the substance having the minimum force of attraction first): Water, Sugar, Oxygen

Ans. Oxygen < Water < Sugar.

(40) Give two reason to justify that :

(a) Water is liquid at room temperature.

(b) An iron almirah is solid.

Ans. (a) The two reasons are :-

(i) Water is not having the fixed shape but it is having a fixed volume. Water takes the shape of the container in which it is kept.

(ii) Water can flow easily from one place to another.

(b) The two reasons that, An iron almirah is a solid are following:-

(i) The molecules of the Iron almirah are bounded by strong force of attraction. As a result they do not take the shape of the vessel and can not be broken easily.

(ii) In addition, the compressibility of Iron Almirah is negligible because of the dense packing of the molecules.

(41) (a) When an incense stick (agarbatti) is lighted in one corner of a room, its fragrance quickly spread in the entire room. Name the process involved in this.

(b) A girl is cooking some food in the kitchen. The smell of food being cooked soon reaches her brother’s room. Explain how the smell could have reached her brother’s room.

Ans. (a) Diffusion.

(b) It is due to the process of diffusion in gas into air.

(42) (a) What does the diffusion of gases tell us about their particles?

(b) Give one example of diffusion of gases in a liquid.

Ans. (a) The process of diffusion gives us two conclusions about the nature of matter:

(i) that matter is made up of tiny particles.

(ii) that the particles of matter are constantly moving.

(b) Gases like carbon dioxide and oxygen present in the atmosphere diffuse into water (of ponds, lakes etc) and dissolves in it.

(43) Give reason for the following observation:

The smell of hot sizzling food reaches us even from a considerable distance but to get the smell from cold food, we have to go close to it.

Ans. The smell of hot sizzling food reaches us even when we are at a considerable distance but to get the smell of cold food, we have to go close to it. This is due to the fact that the rate of diffusion of hot gases is much faster than the rate of diffusion of cold gases released by the cold food.

(44) Explain how the smell of food being cooked in the kitchen reached us even from a considerable distance.

Ans. When food is cooked some of the substances in food release gases having the smell of food in them. The particles these gases move very quickly and mix up with air by diffusion.

(45) Explain why when a bottle of perfume is opened in a room, we can smell it even from a considerable distance.

Ans. The smell of perfume spreads because the diffusion of perfume vapours into it.

(46) When a crystal copper of copper sulphate is placed at the bottom of a beaker containing water, the water slowly turns blue. Why?

Ans. The crystals of copper sulphate dissolve in a little of water around them to form fine particles of copper sulphate in solution. Now the particles of copper sulphate in solution are in motion  and the particles of clear water are also moving. Due to motion of their particles the blue copper sulphate particles in solution move upwards in the beaker and the colourless water particles move downwards and mix with each other. This is called diffusion.

(47) Honey is more viscous than water. Can you suggest why?

Ans. This is because – the force of attraction between the particles of honey is much more than the force of attraction between the particles of water.

(48) Explain why:

(a) air is used to inflate tyres.

(b) Steel is used to make railway lines.

Ans. (a) Air is used to inflate tyres because when we blow air into a tyre the air particles push the tyre walls from inside and exerts pressure on them.

(b) Steel is used to make railway lines because steel is a strong object having a definite shape and definite volume.

(49) Explain why, diffusion occurs more quickly in a gas than in a liquid.?

Ans. This is because the particles in gases move very quickly in all directions whereas the particles in liquids move slowly as compared to the gas particles.

Long answer Type Questions Answers:

(50) (a) What is meant by diffusion? Give one example of diffusion in gases.

(b) Why do gases diffuse very fast?

(c) Name two gases of air which dissolve in water by diffusion. What is the importance of this process in nature.

Ans. (a) The spreading out and mixing of a substance due to the motion of its particles is called diffusion.

Example: Smell of food being cooked in the kitchen reaches us even from a considerable distance.

(b) Gases diffuse very fast because the particles in gases move very quickly in all directions.

(c) Carbon dioxide and Oxygen gas dissolve in water by diffusion.

This process is important as these gases are essential for the survival of aquatic plants and animals. The aquatic plants use the dissolved carbon dioxide for preparing food by photosynthesis and aquatic animals use the dissolved oxygen in water for breathing.

(51) (a) Compare the properties of solids, liquids and gases In tabular form.

(b) Give two reasons for saying that wood is a solid.

(52) (a) Why does gas exert pressure.

(b) Why does a gas fill a vessel completely.

Ans. (a) Gases fills a vessel completely because of high kinetic energy and negligible force of attraction, the particles of a gas move with high speed in all directions. When the fast moving gas particles hit the walls of the container, they exert a pressure.

(b) A gas fills its container completely because due to high kinetic energy and negligible forces of attraction, the particles of a gas are moving with high speeds in all directions.

(53) (a) Define matter. Give four examples of matter.

(b) What are the characteristics of matter.

Ans. (a) Anything which occupies space and has mass is called matter.

Four example of matter are:- air and water, Hydrogen, oxygen, sugar and sand.

(b) The characteristics of matter are:-

(i) Particles of matter have space between them.

(ii) Particles of matter are continuously moving.

(iii) Particles of matter attract each other.

(iv) Particles of matter are too small.

(54) (a) What is Brownian motion? Draw a diagram to show the movement of a particle (like a pollen grain) during Brownian motion.

(b) In a beam of sunlight entering a room, we can sometimes see dust particles moving in a haphazard way in the air. Why do these dust particle move?

Ans. The zig zag movement of the small particles suspended in a liquid or gas is called Brownian motion.

(b)

 


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