Selina Concise Solutions for ICSE Class 6 Chemistry Chapter 3 Matter

POINTS TO REMEMBER

1. Horse, mango tree, dog, animals, plants are living, while stone, pen, glass, water, book, table, air are non-living.
2. All the above mentioned things living and non-living are matter.
3. Energies like light, sound, heat are not matter, as these have no mass.
4. Matter : “Anything that has mass and occupies space is called matter.” Matter (mass) remains same at all places.
5. Molecules of matter are in motion.
6. The things which are similar in one or more ways are grouped together and this practice is classification.
7. There are inter-molecular gaps (spaces) and inter-molecular attraction (force of attraction) between molecules.
8. Solids are rigid, have definite volume, retain their shape and are incompressible.
9. Liquids can flow, have definite vol., have no definite shape. Have only one free surface.
10. Gases Have no definite volume, no definite shape can flow are compressible.
11. Inter-molecular force : Solids > Liquids > Gases.
12. Inter-molecular volume : Solids < Liquids < Gases.

Activity 1

Question 1: List five substances made using each of the following materials:

Answer:
1. Wood : Chair
2. Paper : Book
3. Plastic : Bucket
4. Metals : Copper wire
5. Leather : Shoes
6. Cloth : Shirt or bag
Everything around us is made of different types of matter. These examples show how we use raw materials like wood or leather to create objects for our daily needs.
Teacher's Tip: Think of "Materials" as the ingredients and "Substances" as the finished dish.
Exam Tip: When listing examples, try to choose distinct objects to show a wide understanding of the material's use.

EXERCISE- I

Question 1: Define matter.

Answer:
Anything that has mass and occupies space is called matter.
This means that everything from the air you breathe to the desk you sit at is matter because it takes up room and has weight. If something doesn't have mass, like light or sound, it is not considered matter in science.
Teacher's Tip: Use the "M-S" rule - Matter has Mass and Space.
Exam Tip: Always include both "mass" and "space" in your definition to get full marks.

Question 2: What are the two main types of matter? Give two examples for each type.

Answer:
The two main types of matter are :
1. Living matter: The earth is home to all kinds of plants and animals. They can grow, move and reproduce on their own. Examples : Plant, lotus, animals, human etc.
2. Non-living matter : Most of the matter in the universe is non-living. It means that it does not grow, move or reproduce on its own. It can be natural or man made.
(a) Natural matter: It occurs in nature and can be used to make more useful substances, e.g., wood, coal, silk, water, stone, cotton, jute, cereals, fruits, etc.
(b) Man-made matter : It is produce artificially from natural matter, e.g., plastics, soaps, detergents, medicines, glass, nylon, steel, ceramic, etc.
Matter can be found in biological forms that breathe and grow, or as inanimate objects found in nature or built by people. Understanding these categories helps us classify everything we see in the natural world and in our homes.
Teacher's Tip: If it can breathe or grow on its own, it is "Living" matter.
Exam Tip: When giving examples for man-made matter, choose common items like "plastic" or "glass" to ensure your answer is easily understood.

Question 3: Differentiate between living and non-living matter.

Answer:
Living matter:
1. The earth is home to all kinds of plants and animals. They can grow, move and reproduce on their own.
2. It is natural only.
Non-living matter:
1. Most of the matter in the universe is non-living. It means that it does not grow, move or reproduce on its own.
2. It can be natural or man made.
The biggest difference is the ability to carry out life processes like growth and reproduction. While all living things are natural, non-living things can be either found in nature or created by humans in factories.
Teacher's Tip: Remember the 3 G's for living things: Grow, Go (move), and Generate (reproduce).
Exam Tip: Present your answer in two clear sections or a table to show the comparison effectively.

Question 4: Select natural and man made matter from the following list: Wood, plastic, silk, medicines, detergents, coal, water, ceramic, cotton, glass, nylon, fruits.

Answer:
Natural matter: Wood, silk, coal, water, fruits.
Man made matter: Plastic, medicines, detergents, ceramic, cotton, glass, nylon.
Natural matter is provided by the earth without any human processing, while man-made matter is synthesized by us using chemical methods. Distinguishing between these allows us to understand the origin of the materials we use every day.
Teacher's Tip: If you can find it in a forest or a mine, it's usually "Natural."
Exam Tip: Be careful with items like "cotton"; though it grows on a plant, the finished fabric in the list is often categorized by its processed state in many contexts, but stick to the textbook classification provided.

EXERCISE-II

Question 1: Name the smallest particle from which matter is made up.

Answer:
The smallest particle from which matter is made up is atom.
Atoms are like the tiny building blocks of the entire universe. Even though they are too small to see with our eyes, they combine in billions to form everything around us.
Teacher's Tip: Think of an "Atom" as a single LEGO brick.
Exam Tip: Use the word "building block" if you need to explain what an atom does for matter.

Question 2: What are molecules?

Answer:
Molecules are the smallest unit of matter. They exhibit all the properties of that kind of matter and is capable of independent existence.
When atoms join together, they form molecules, which are the smallest pieces of a substance that still act like that substance. For example, a molecule of water still has all the characteristics of water.
Teacher's Tip: A molecule is a "Team" of atoms working together.
Exam Tip: Don't forget to mention "independent existence," as this is a key scientific property of molecules.

Question 3: Give one difference between atoms and molecules.

Answer:
Atoms may or may not have independent existance. While molecules have independent existence.
This means that some atoms are too unstable to stay alone and must join others, while a molecule is stable enough to exist by itself. Molecules are essentially the functional units that make up the materials we can see and touch.
Teacher's Tip: Atoms are the "letters" and molecules are the "words" of matter.
Exam Tip: Keep the difference simple by focusing on the "stability" and "existence" of the two particles.

Question 4: Define:
(a) Inter-molecular force of attraction.
(b) Inter-molecular space.

Answer:
(a) The molecules of matter are always in motion and attract each other with a force, and this force is called inter-molecular force of attraction due to which they are held together.
(b) The molecules can move only when there are gaps or space between them, this space is called inter-molecular space.
Think of the force as an invisible glue that keeps molecules from flying apart. The space between them determines how much room they have to move and shift around.
Teacher's Tip: Space is the "Gap" and Force is the "Hug" between molecules.
Exam Tip: Use the prefix "inter-" to remind yourself that these things happen "between" different molecules.

Question 5: Name the three states of matter and define them.

Answer:
The three states of matter are :
1. Solid State : The molecules are very close to each other hence inter-molecular spaces are small and inter-molecular force is strong. Hence solids have definite volume, rigid, retain definite shape and are incompressible.
2. Liquids : The molecules are less closely packed have more inter-molecular spaces than solid, less stronger forces than solids. Hence liquids have definite volume but no definite shape. They take the shape of container in which they are put.
3. Gases : The molecules in the gases are far apart with weakest force of attraction. Hence gases have neither definite volume nor definite shape but easily compressible.
Matter changes its state based on how close its molecules are and how strongly they pull on each other. These differences explain why you can pour a liquid but you have to pick up a solid.
Teacher's Tip: Solids are "Stiff," Liquids "Leap" (flow), and Gases "Go" everywhere.
Exam Tip: When defining these states, always mention "shape" and "volume" for each one to get full marks.

Question 6: What are fluids ? Give two examples

Answer:
Substances that can flow are called fluids. Both gases and liquids are fluids, e.g. gases (carbon dioxide, hydrogen), liquids (water, petrol and sulphuric acid).
Fluids are unique because their molecules aren't fixed in place, allowing them to slide past one another and move. This is why both water and air can move through pipes or around obstacles.
Teacher's Tip: Remember: "Fluid = Flow."
Exam Tip: Be sure to include both liquids AND gases in your definition of fluids.

Question 7: Classify the following into solids, liquids and gases.
Oxygen, milk, common salt, wax, stone, L.P.G, carbon- dioxide, sugar, mercury, coal, blood, butter, copper, coconut oil, kerosene.

Answer:
Solids: Common salt, Wax, Stone, Sugar, Coal, Butter, Copper.
Liquids: Milk, Mercury, Blood, Coconut oil, Kerosene.
Gases: Oxygen, L.P.G., Carbon dioxide.
Classification helps us group substances by their physical properties like rigidity and flow. By looking at whether an item has a fixed shape or fills a room, we can easily place it into one of these three categories.
Teacher's Tip: If it splashes, it's usually a liquid; if it's hard, it's a solid; if you can't see it but can breathe it, it's a gas!
Exam Tip: Mercury is a common trick question; remember that even though it is a metal, it is a liquid at room temperature.

Question 8: Give reasons
(a) Liquids and gases flow but solids do not ?
(b) A gas fills up the space available to it.
(c) The odour of scent spreads in a room.
(d) We can walk through air.
(e) Liquids have definite volume but no definite shape.
(f) When a teaspoon of sugar is added to half a glass of water and stirred, the water level in the glass remains unchanged.
(g) When an empty gas jar is inverted over a gas jar containing a coloured gas, the gas also spreads into the empty jar.
(h) A red ink drop added to small amount of water in a glass turns the water red in some time.

Answer:
(a) The molecules of liquids and gases are far apart i.e. have more gaps, inter-molecular attraction force is very less as compared to solids, hence liquids and gases can flow but solids do not as gaps in solid molecules is less and molecular force of attraction very strong.
(b) Inter-molecular force of attraction is least and inter-molecular spaces are very large, hence gases can fill up the space available to them.
(c) Scent fumes (molecules) being gases fill the spaces between air molecules and the molecules of air fill the spaces between scent molecules due to diffusion, fumes spread into a room.
OR
Due to inter-mixing of scent molecules and air molecules, scent fumes spread into the room.
(d) The molecules of air are far apart i.e. large gaps and we can walk through air easily.
(e) The molecules of liquid are loosely packed and inter-molecular force of attraction is small but number of molecules in it remain the same. Hence liquids have definite volume but no definite shape.
(f) When a teaspoon of sugar is added to half a glass of water and stirred, the water level in the glass remains unchanged because the sugar particles are adjusted between the water molecules as inter-molecular gaps are more in liquids.
(g) This is because Gases can diffuse or flow in all directions.
(h) When we put a drop of red ink in a glass of water, its particles diffuse with particles of water slowly but continuously and the water turns red.
These behaviors are all explained by how molecules are arranged and how they move. Whether it is ink mixing with water or walking through air, the "spaces" between molecules are the reason these everyday events happen.
Teacher's Tip: Imagine molecular spaces as the seats in a theater; if they are empty, you can move around easily!
Exam Tip: For "Give Reason" questions, always use the keyword "diffusion" when talking about smells or colors spreading.

Question 9: Define:
(a) cohesive force
(b) diffusion
(c) Brownian movement

Answer:
(a) Cohesive force : The force of attraction between particles of the same substance is called cohesive force.
(b) Diffusion: The phenomenon of intermixing of particles of one kind with another kind is called diffusion.
(c) Brownian movement: The zig-zag motion of particles suspended in a medium is called Brownian movement.
Cohesive force is why a drop of water stays together as a round bead. Diffusion and Brownian movement describe how particles are constantly on the move, crashing into each other and spreading out in their environment.
Teacher's Tip: Brownian movement is like a "Bumper car" ride for tiny particles.
Exam Tip: Use the term "zig-zag" specifically when defining Brownian movement to satisfy examiners.

Question 10: Why is an egg kicked out of a bottle when air is blown inside the bottle?

Answer:
When we invert the bottle and blow air into the bottle throw the side opening. It creates high pressure inside the bottles and the egg is kicked out of the bottle.
Blowing air increases the number of molecules inside the bottle, which pushes against the walls and the egg. This "high pressure" acts like a strong hand that shoves the egg back out through the opening.
Teacher's Tip: High pressure always wants to move toward low pressure!
Exam Tip: Mention "high pressure" as the specific cause for the egg moving out.

EXERCISE-III

Question 1: State the three effects of heat on matter.

Answer:
When a substance is heated, it can cause.
1. Interconversion of states of matter.
2. Thermal expansion of the substance.
3. Chemical change.
Heat adds energy to molecules, making them move faster and push away from each other. This energy can simply make an object grow larger, change its form from ice to water, or even create a whole new substance through a reaction.
Teacher's Tip: Heat is "Hustle" for molecules - it makes them move more!
Exam Tip: List all three effects clearly with numbers to show you understand the full impact of heat.

Question 2: (a) Define : interconversion of states of matter.
(b) What are the two conditions for the interconversion of states of matter ?

Answer:
(a) The process by which matter changes from one state to another and back to original state, without any change in its chemical composition.
(b) Two conditions are :
1. Change in temperature
2. By applying pressure
This means you can turn water to steam and then cool it back into water without ever changing it into something else. By simply twisting the "dials" of heat and pressure, we can control what state matter exists in.
Teacher's Tip: Think of it as a "Round trip" for matter - it goes and comes back.
Exam Tip: Always specify that the "chemical composition" does NOT change during interconversion.

Question 3: Define the following terms:
(a) Fusion
(b) Vaporisation
(c) Condensation
(d) Sublimation
(e) Diffusion
(f) Melting point
(g) Boiling point
(h) Liquefaction

Answer:
(a) Fusion : The heating process by which a solid changes into the liquid state is called fusion.
(b) Vaporisation : The heating process by which a liquid changes into its vapour state is called vaporisation.
(c) Condensation : The process by which a substance in gaseous state changes into its liquid state is called condensation.
(d) Sublimation: The change of solid on heating to vapours directly and vice-versa without passing through the liquid state is called sublimation.
Solid --heating--> Vapour / Vapour --cooling--> Solid.
(e) Diffusion : The phenomenon of intermixing or spreading of gaseous molecules is called diffusion.
(f) Melting point: The fixed temperature at which a solid changes into a liquid at a given pressure is called its melting point. The temperature remains constant as long as the conversion is going on.
(g) Boiling point: The fixed temperature at which a liquid starts changing into gaseous state is called its boiling point. The temperature remains constant till the whole of the liquid changes into gaseous state.
(h) Liquefaction : Change of vapours on cooling to liquid is called liquefaction.
Each of these terms describes a specific "pathway" matter takes when its energy level changes. Knowing these allows us to talk precisely about how substances like ice or steam behave under different temperatures.
Teacher's Tip: "Sublimation" is the shortcut - it skips the liquid step entirely!
Exam Tip: When defining melting or boiling points, always mention that the temperature remains "constant" during the change.

Question 4: Differentiate between:
(a) Solidification and condensation
(b) Melting and boiling
(c) Gas and vapour
(d) Miscible and immiscible liquids.

Answer:
(a) Solidification : The process of changing liquid into a solid state by cooling is known as solidification. Example : water -> ice.
Condensation : The process of changing a gas or vapour state to a liquid state by cooling is known as condensation. Example : steam -> water.
(b) Melting : The fixed temperature at which a solid changes into a liquid at a given pressure is called its melting point. e.g. ice -> water.
Boiling : The fixed temperature at which a liquid starts changing into gaseous state is called its boiling point. e.g. water -> steam.
(c) Vapourisation : The process by which a substance changes from a liquid state to vapour state is called vaporisation or evaporation. e.g., Water changes into gaseous state on heating.
Gas : The substance which remain in the gaseous state under normal conditions of temperature and pressure are called gases. e.g, Oxygen, hydrogen, nitrogen.
(d) Miscible: Liquids which mix with each other are called miscible liquids. Example : Water and alcohol.
Immiscible liquids : Liquids which do not mix with each other are called immiscible liquids. Example Water and oil.
These definitions help us distinguish between similar-sounding processes and properties. For instance, knowing the difference between miscible and immiscible is vital when trying to mix chemicals or kitchen ingredients safely.
Teacher's Tip: "Miscible" sounds like "Mix-able."
Exam Tip: Always provide an example like "Water and Oil" when differentiating between miscible and immiscible liquids.

Question 5: Give reasons :
(a) How is interconversion of states of matter different from chemical reaction ?
(b) Why a solid does not flow, but a liquid flows ?

Answer:
(a) During interconversion of state of matter composition of substance remains the same matter changes from one state to another and back to the original state, while chemical reaction involves re-arrangement of the molecular structure and composition changes.
(b) In solids there is a strong force of attraction between the molecules and the space between them is very negligible. The molecules are therefore, not free to move. They merely vibrate about their mean positions. But in the case of liquids, the molecules are not very closely packed. They do not attract each other as strongly as the molecules of solids. Thus, the inter-molecular spaces are larger and the molecules are able to move about more freely. This makes a liquid flow.
The core difference lies in whether the internal "ID" of the substance changes. In interconversion, the substance stays the same; in a chemical reaction, it becomes something brand new with different molecules.
Teacher's Tip: Interconversion is like changing your clothes; a chemical reaction is like turning into a different person!
Exam Tip: Use the phrase "re-arrangement of molecular structure" when explaining a chemical reaction to score higher.

Question 6: How does a liquid changes into its gaseous state? Explain ?

Answer:
As a liquid is heated, its particles starts gaining energy and move more vigorously which increases the gaps between the particles and decreasing the force of attraction. Ultimately a liquid changes into gaseous state.
When we heat a liquid, we are basically "super-charging" its molecules until they are fast enough to break free from the group. Once they overcome the pull of their neighbors, they fly out into the air as gas particles.
Teacher's Tip: Heat is the "Escape energy" for liquid molecules.
Exam Tip: Mention both "increased gaps" and "decreased force" to fully explain the change to a gas.

Question 7: Water cycle is an example of interconversion of states of water. Explain.

Answer:
Water from oceans, rivers, lakes from leaves of trees (transpiration) changes into vapours when temperature increases or evaporates and enters the atomsphere as clouds when temperature falls the vapours change into water and some of it in the form of snow fall on mountains and earth in the form of water and hails and this continues. Thus water cycle is example of interconversion of states of water.
Nature uses the water cycle to constantly recycle water by switching it between liquid, vapor, and solid (ice/snow). This continuous loop ensures that water moves all around the planet, powered entirely by the sun's heat and the earth's cooling.
Teacher's Tip: Think of the sun as the earth's giant heater that starts the cycle.
Exam Tip: Use terms like "evaporation" and "condensation" to explain the different steps of the water cycle.

Question 8: What happens to a metal ball when it is heated? What does this show?

Answer:
When metal ball is heated, it expands. This can be proved by following experiment:
Take a metallic ring and ball. Try to pass the metal ball through the ring. The ball is able to pass through the ring. Now heat the metal ball for 5-6 minutes. The hot ball is not be able to pass through the ring. This shows that a solid expands on heating. Now cool the ball, it again passes through the ring. This shows that a solid contacts on cooling.
This experiment demonstrates "thermal expansion," where heat causes the atoms in the metal to vibrate harder and take up more room. As it cools, the vibrations slow down, the atoms settle back together, and the ball shrinks back to its original size.
Teacher's Tip: Heat makes the ball "too big for its britches" (the ring)!
Exam Tip: Drawing a simple diagram of the ball and ring setup will help your explanation of expansion and contraction.

Question 9: Why does a candle become smaller on burning with time?

Answer:
On heating, candle wax melts, then turns into vapour which reacts with air to produce two new substances, carbon dioxide and water.
Burning -- Candle wax --heating--> Carbon dioxide + Water vapour.
Therefore a candle on burning becomes smaller and smaller and the part of wax which has undergone chemical change cannot be recovered.
This is because a candle isn't just melting; it's also fueling a chemical reaction called combustion. The wax is physically turning into gases that fly away into the room, which is why you can't get that wax back once it's burned.
Teacher's Tip: Candle wax is "Fuel" that turns into invisible gas when it burns.
Exam Tip: Specify that this is a "chemical change" to explain why the wax cannot be recovered.

OBJECTIVE TYPE QUESTIONS

Question 1: Fill in the blanks :
(a) Water is a matter because it has mass and occupies space.
(b) Any matter which has a definite volume but no definite shape is called a liquid.
(c) Liquids and gases can flow.
(d) The molecules are at a greater distance in gases compared to liquids.
(e) Water boils at $100^{\circ}C$.
(f) The physical state of a substance, which has neither fixed volume nor fixed shape is a gas.

Question 2: Write whether the following statements are true or false.
(a) Only water can exist in three different states.
(b) If the container in which a gas is collected has an opening, the gas will flow out and spread itself indefinitely.
(c) Solids have the largest inter-molecular space.
(d) There is no difference between evaporation and boiling.
(e) All solids, on heating, first change to the liquid and then to the gaseous state always.
(f) The inter-molecular force of attraction is the weakest in gases.
(g) A gas has no free surface.

Answer:
(a) True
(b) True
(c) False. Correct: Solids have the very small (negligible) inter-molecular space.
(d) False. Correct : There is a difference between evaporation and boiling.
(e) False. Correct : Few solids, on heating, first change to the liquid and then to the gaseous state always.
(f) True
(g) True
These statements test your understanding of molecular motion in different states. Knowing these facts helps you predict how matter will behave under different environmental conditions.
Teacher's Tip: Remember, "False" answers need a "Correct" fact to be complete.
Exam Tip: When answering True/False, always read the entire sentence carefully as one wrong word can change the whole meaning.

Question 3: For each of the following statements, say whether it describes a solid, a liquid or a gas.
(a) Particles move about very quickly but do not leave the surface : Liquid
(b) Particles are quite close together : Solid
(c) Particles are far apart and move in all directions : Gas

Question 4: Match the following :

Column A
(a) Solids
(b) Sublimation
(c) Boiling point
(d) Gases
(e) Intermolecular space

Column B
(i) Can flow in all directions.
(ii) The temperature at which a liquid changes into its gaseous state.
(iii) Can have any number of free surfaces.
(iv) Gaps between particles.
(v) Change of state from solid to gas.

Answer:
(a) Solids - (iii) Can have any number of free surfaces.
(b) Sublimation - (v) Change of state from solid to gas.
(c) Boiling point - (ii) The temperature at which a liquid changes into its gaseous state.
(d) Gases - (i) Can flow in all directions.
(e) Intermolecular space - (iv) Gaps between particles.
This matching exercise connects different states of matter and scientific processes to their specific behaviors and definitions. Understanding these properties helps us explain why solids maintain their shape while gases can fill a whole room instantly.
Teacher's Tip: Think of Sublimation as the "Subway" shortcut - it goes straight from solid to gas without stopping at the liquid station!
Exam Tip: When writing matching answers in your exam, always write out the full correct pair (A + B) side-by-side to ensure the examiner can read it clearly and give you full marks.

Question 5: Name the phenomenon which causes the following changes:
(a) Formation of water vapour from water.
(b) Disappearance of camphor when exposed to air.
(c) Conversion of ice into water.
(d) Conversion of water into steam.

Answer:
(a) Formation of water vapour from water is vaporisation.
(b) Disappearance of camphor is sublimation.
(c) Conversion of ice into water is melting.
(d) Conversion of water into steam is boiling.
These phenomena are everyday examples of matter changing state due to energy changes. Whether it's the smell of camphor or water turning to steam, these scientific terms describe the invisible movement of molecules.
Teacher's Tip: "Sublimation" is the magic trick where a solid turns into gas and disappears!
Exam Tip: Make sure to use the exact term like "vaporisation" or "melting" rather than general words like "turning into."

Question 6: Give two examples for each of the following :
(a) Substances which sublime.
(b) Substances which do not change their states.
(c) Substances which are rigid and not compressible.

Answer:
(a) Naphthalene, camphor, dry ice.
(b) Oxygen, hydrogen, nitrogen
(c) Glass, stone, pen.
Knowing these examples helps us identify how different substances behave in our world. For instance, knowing dry ice sublimes tells us it will turn straight into cold gas without leaving a puddle.
Teacher's Tip: "Rigid" things are the ones that hurt if you bump into them!
Exam Tip: Memorize "Naphthalene" and "Camphor" as your go-to examples for sublimation.

MULTIPLE CHOICE QUESTIONS

1. Which one is a kind of matter :
(a) light
(b) petroleum
(c) sound
(d) heat
Answer: (b) petroleum

2. the state of matter which has no definite shape or volume is called
(a) solid
(b) liquid
(c) gas
(d) water
Answer: (c) gas

3. There are large inter-molecular gaps in
(a) water
(b) iron ball
(c) common salt ..
(d) air
Answer: (d) air

4. All kinds of matter
(a) occupy space and have a definite mass
(b) have mass and a definite shape
(c) can change their states
(d) have a definite volume
Answer: (a) occupy space and have a definite mass

5. A kind of matter which can sublime is
(a) water
(b) plastic
(c) milk
(d) iodine
Answer: (d) iodine

6. A substance which can change its state
(a) wood
(b) oxygen
(c) paper
(d) cloth
Answer: (b) oxygen

7. The process by which a solid changes into a liquid is called
(a) freezing
(b) melting
(c) condensation
(d) evaporation
Answer: (b) melting

PROJECT

Question 1: Fill the following chart showing twelve solids, twelve liquids, four gases and eight materials.

Answer:
Solids : (1) Mobile. (2) Pen. (3) Pair of shoes. (4) A T.V. set (5) Chair. (6) Telephone. (7) Remote control. (8) Wood. (9) Ornaments. (10) Scissors. (11) Eraser. (12) Mirror.
Liquids : (1) Ink. (2) Water. (3) Lemon juice. (4) Cough syrup. (5) Mouth wash. (6) Petrol. (7) Kerosene oil. (8) Spirit. (9) Thinner. (10) Mercury. (11) Milk. (12) Copper sulphate solution.
Gases : (1) Hydrogen. (2) Oxygen. (3) Sulphur dioxide. (4) Chlorine gas.
Materials : (1) Paper. (2) Wood. (3) Iron nails. (4) Cement. (5) Tiles. (6) Plaster of paris. (6) Sand. (7) Iron rods. (8) Bricks.
This extensive list helps you recognize matter in its many forms throughout your home and city. Classifying items into these groups makes studying their physical properties much more organized.
Teacher's Tip: Most of your school supplies like "Pen" or "Eraser" are great examples of solids.
Exam Tip: When making a chart like this, keep common items grouped together so you don't forget any!

Question 2: Think and try to find a way to demonstrate water cycle in class.

Answer:
Do it yourself.
A great way is to put a bit of water in a clear plastic bag, tape it to a sunny window, and watch it evaporate and condense. This mini-model shows exactly how rain forms in nature.
Teacher's Tip: Use a permanent marker to draw a sun and clouds on your "Water cycle bag."
Exam Tip: Be prepared to explain that "evaporation" is the stage where liquid water turns into an invisible gas.

Question 3: To identify materials of common use. Procedure – Just move around in your house – in the drawing room, sitting room, bedroom, kitchen, bathroom etc. Identify the things and All in the blanks in the table given below:
Study room
Drawing room
Kitchen
bathroom
another place

Answer:
S.No. 1 Place: Study room; Name of thing: Table, chair, books pens, pencils, table lamp, computer, fan; Material used: Wood, plastic, paper, glass, bakelite, connecting wires made of metal and plastics.
S.No. 2 Place: Drawing room; Name of thing: Sofa, table, chairs, fan, curtains, windows etc.; Material used: Wood, cloth, coir, paint, plastics, aluminium, glass etc.
S.No. 3 Place: Kitchen; Name of thing: Taps, wash basin, cupboards, utensils, heating vessels strainer, containers aqua pure etc.; Material used: Steel, aluminium, glass, china clay, iron, plastic, copper, stainless steel, brass etc.
S.No. 4 Place: Bathroom; Name of thing: Taps, tubs, mugs, tooth brush, tooth paste, soap, pail etc.; Material used: Iron, brass, stainless steel, plastics etc.
S.No. 5 Place: Any other place; Name of thing: Scooter, car, road, rooms, trucks, shops.; Material used: Iron, rubber, coaltar, bricks, wood, plastics, clothes.
By looking at everyday objects, you can see how many different materials go into making them. Understanding these materials helps us choose the best ones for specific tasks, like using steel for cooking pots or rubber for tires.
Teacher's Tip: Check your toothbrush; you'll find at least two different types of plastic and some bristles!
Exam Tip: When identifying materials, try to find hidden ones, like the "metal" inside an electrical wire.

ADDITIONAL QUESTIONS FOR PRACTICE
Exercise

Question 1: Explain the term ‘matter’. One kind of matter can be distinguished from another by its physical properties and chemical properties. State the main physical properties of matter.

Answer:
Matter is the basic substance of which all materials are made of.
Physical Properties— They are those properties which include state, colour, odour, density etc.
Chemical Properties— They are properties which include reactions of different materials with different chemical.
Physical Properties of Matter are :
Colour : All matter an be distinguished by their varied- colours.
Odour : Matter shows variation in odour or smell.
Solubility : Matter may vary in solubulity in water or other solvents.
Melting & Boiling Points : Substances variation in their melting and boiling points.
Everything we touch is matter because it takes up space and has weight. Understanding physical properties like color and smell allows us to identify different types of matter without changing them.
Teacher's Tip: Think of matter as anything you can "weigh" and "put in a box."
Exam Tip: Be sure to differentiate between "Physical" (appearance) and "Chemical" (how it reacts) when describing properties.

Question 2: The three main states of matter are solids, liquids and gases. Compare the three states with reference to the following characteristics of matter
(a) volume
(b) shape
(c) compressibility
(d) diffusion.

Answer:
Volume : Solids: Have a definite volume; Liquids: Have a definite volume; Gases: Have no definite volume.
Shape : Solids: Have a definite shape; Liquids: Have no definite shape; Gases: Have no definite shape.
Compressibility : Solids: Cannot be compressed; Liquids: Slightly compressible; Gases: Highly compressible.
Diffusion [Intermingling of Molecules] : Solids: Cannot diffuse; Liquids: Shows diffusion; Gases: Diffuses very easily.
This comparison highlights why solids keep their shape while gases spread out to fill any container. It is all down to how tightly the particles are packed and how much they can move.
Teacher's Tip: Use a sponge as a mental model for compressibility - solids usually don't squeeze, but gases do!
Exam Tip: In comparison tables, always use the same parameters (like shape or volume) for all three states for a neat answer.

Question 3: Matter in any state is composed of particles. Compare the three states of matter Le. solids, liquids and gases with reference to :
(a) inter-molecular space
(b) inter-molecular force of attraction
(c) movement of particles

Answer:
Inter-molecular space : Solids: Minimum space; Liquids: More than solids; Gases: Maximum space.
Inter-molecular Force of attraction : Solids: Very strong; Liquids: Less strong; Gases: Very weak.
Movement of particles : Solids: About their own position; Liquids: In continuous motion; Gases: In any random direction.
The strength of the force of attraction is what keeps a solid from falling apart. In gases, this force is so weak that particles simply fly away from each other in all directions.
Teacher's Tip: Imagine solid particles as people holding hands tightly, and gas particles as people running in a park.
Exam Tip: Remember that "space" and "force" are opposites - minimum space means maximum force.

Question 4: Describe simple experiments to prove that – solids
(a) occupy space
(b) have mass
(c) have a definite volume

Answer:
(a) occupy space : solid-occupies space
‘A’-A measuring cylinder is filled with water to a particular mark- ‘A’.
‘B’-A piece of wooden block- is immersed inside the measuring cylinder. The water level rises up. .
‘C’-On removal of the block- the water level in the measuring cylinder falls down back to the mark- ‘A’
Conclusion : The block pushes the water out and occupies its space, hence all solids occupy space.
(b) Have mass – A solid has mass
A : A simple scale – is taken, as shown below
B : A solid is placed – on one side of the scale, causes the scale tilts towards one side.
Conclusion – The scale tilts due to the mass of the solid, hence all solids have mass.
(c) Have a definite volume : A solid placed in any container filled with water displace the same amount of water.
Conclusion : Solid displace water and retain their own volume, hence all solids have a definite volume.
These experiments give us clear, visible evidence of the physical laws that govern matter. By seeing water rise or a scale tip, we confirm that even if we can't see atoms, the bulk materials they form behave in predictable ways.
Teacher's Tip: Try the water-rising experiment yourself at home with a glass and some pebbles!
Exam Tip: When describing experiments, always clearly state the "Conclusion" to show you understood the result.

Question 5: Describe simple experiments to prove that – liquids
(a) have mass
(b) have a definite volume
(c) have no definite shape

Answer:
(a) have mass a liquid occupies mass
Experiment : A liquid placed on one side of the scale, causes the scale to tilt towards one side.
Conclusion : The scale tilts due to the mass of the liquid, hence all liquids have mass.
(b) have a definite volume
Experiment : A liquid in a measuring cylinder can be poured into any container. The volume of liquid in the container, is the same as that in the measuring cylinder.
Observation : The volume of liquid in the container, is the same as that in the measuring cylinder. Hence, all liquids have a definite volume.
(c) have no definite shape
Experiment : A liquid poured into any container takes up the shape of each container.
Conclusion : All liquids have no definite shape.
These properties explain why liquids are so versatile - they carry weight but can also adapt to the shape of any bottle. This adaptability is what allows fluids to flow through pipes and fill containers of all different designs.
Teacher's Tip: A liter of milk is still a liter, whether it's in a jug or a flat bowl.
Exam Tip: Mention the "measuring cylinder" to show that you understand how we scientifically prove volume remains definite.

Question 6: Describe simple experiments to prove that – gases
(a) occupy space
(b) have mass
(c) have no definite volume or shape

Answer:
(a) occupy space
Experiment
‘A’ – A glass beaker or bowl is half filled with water.
‘B’ – An empty glass tumbler [which of course contains air] is inverted an lowered inside it.
‘C’ – On tilting the tumbler, air is displaced and bubbles are seen coming out.
Conclusion : Air or gases occupy space.
(b) Have mass
Experiment
An inflated balloon placed on one side of the scale causes it to tilt towards one side.
Conclusion : The scale tilts due to the mass of the gas, hence all gases have mass.
(c) Have no definite volume or shape
Experiment
A gas takes up the volume of any enclosed space filling it up completely.
Conclusion : Gases take up any volume and hence all gases have no definite volume.
Even though air is invisible, these experiments prove it is "real" matter with weight and physical presence. The balloon and the bubble experiments are classic ways to "see" the invisible forces of gases at work.
Teacher's Tip: Invisible doesn't mean it's not there! If you can blow it into a balloon, it has mass.
Exam Tip: In the bubble experiment, explain that "displacement" is the reason bubbles appear when you tilt the glass.

Question 7: Explain the term ‘Intercon version of matter’. With reference to ice, water and water vapour show diagrammatically the change of state of matter from solid to liquid to gaseous and back to original state.

Answer:
INTERCONVERSION OF MATTER : “Change of state of matter from one state to another state and back to its original state is called inter-conversion of matter.” The diagram showing the Change of State of Matter :
(a) ICE TO WATER (MELTING) : Conversion of a solid into a liquid on heating e.g. ice to water.
(b) WATER TO WATER VAPOUR (VAPORISATION): Conversion of a liquid into vapours (or gas) on heating e.g. water to water vapour.
(c) WATER VAPOUR TO WATER (LIQUEFACTION or CONDENSATION) : Conversion of VAPOUR (or gas) into a LIQUID on cooling e.g. water vapour to water.
(d) WATER TO ICE (SOLIDIFICATION OR FREEZING) : Conversion of a LIQUID into a SOLID e.g. water to ice.
Matter doesn't always stay in one form; it can switch between solid, liquid, and gas depending on the heat around it. This process is reversible, meaning we can turn ice to water and then freeze it back into ice again.
Teacher's Tip: Remember "Heat for change, cool for back."
Exam Tip: When asked to show something diagrammatically, use clear arrows to show the direction of heating and cooling.

Question 8: Explain the terms
(a) melting (b) vaporization (c) condensation (d) freezing (e) melting point (f) boiling point.

Answer:
Matter can change from solid to liquid to gaseous state and back to solid state. This is called change of state of matter.
(a) Melting— The process of conversion of a solid into liquid on heating. e.g. Ice to water.
(b) Vaporization— The process of conversion of a liquid into vapour on heating. e.g. Water to water vapour.
(c) Condensation— The process of conversion of vapour into a liquid. e.g. Water vapour to water.
(d) Freezing— The process of conversion of a liquid into a solid. e.g. Water to ice.
(e) Melting point— The constant temperature at which a solid melts into a liquid. M.P. of ice – $0^{\circ}C$.
(f) Boiling point— The constant temperature at which a liquid starts boiling. B.P. of water – $100^{\circ}C$.
Each of these terms describes a specific "step" in the journey matter takes as it gains or loses energy. By learning these names, we can precisely describe scientific processes like how clouds form or why ice cubes disappear.
Teacher's Tip: "Condensation" is why your cold soda can feels "sweaty" on a hot day!
Exam Tip: Always include specific temperature examples like "$0^{\circ}C$" or "$100^{\circ}C$" to demonstrate precision.

Question 9: State what would you observe if (a) sugar is added to pebbles take in a plastic beaker (b) sand is added to glass balls in a beaker. What would you conclude from this imaginative demonstration.

Answer:
Experiment : Add sugar to pebbles taken in a plastic beaker or sand to glass balls in a beaker.
Observation : The sugar or the sand goes into the space between the pebbles & the glass balls respectively.
Conclusion : An imaginative demonstration to show that inter-molecular spaces between particles are occupied easily.
This thought-experiment helps you picture what is happening at a microscopic level. It shows that there is plenty of room between molecules for other, smaller particles to slip inside and hide.
Teacher's Tip: Think of the pebbles as molecules and the sugar as even smaller molecules filling the gaps.
Exam Tip: Clearly state that the sugar "occupies the gaps" to get the point about inter-molecular space across.

Question 10: With the help of a simple diagram how would you show that – solids expand on heating

Answer:
Solids expand on heating can be shown by two different experiments. The experiments are :
Experiment A : An iron bar is taken and its length measured accurately. The iron bar is then slowly heated for a certain period of time & measured accurately [with a vernier calipers or otherwise]
Observation : It is observed that the iron bar has increased in length on heating.
Experiment B : A simple ball & ring apparatus is taken, which consists of a metal ball which can just pass through the circular metal ring. The metal ball is then heated for a certain period of time.
Observation : After heating, the metal ball does not pass through the ring, since on heating it has expanded in size and hence cannot pass through the ring.
Conclusion : All solids expand on heating.
These experiments demonstrate that thermal energy causes the particles in a solid to vibrate more and move slightly apart. This small increase in space between particles results in the overall expansion of the material.
Teacher's Tip: Remember the "Hot Ball" - heat makes things grow!
Exam Tip: Drawing the "Ball and Ring" diagram in exams helps clarify your explanation of thermal expansion.

Question 11: Give reasons for the following :
(a) Solids have a definite shape and are highly rigid while gases have to definite shape and are least rigid.
(b) Sugar can be distinguished from talcum powder using water.
(c) Water on freezing turns into ice.
(d) A bottle of perfume on opening evolves an odour which can be sensed over a long distance.

Answer:
(a) Solids have very closely packed atoms with minimum spaces between them while gases have atoms which are for apart with maximum spaces between them. Solids have a definite shape and are highly rigid while gases have no definite shape and are least rigid.
(b) Sugar is soluble in water whereas talcum powder is not.
(c) Every pure substance has a fired melting point or boiling point.
(d) A bottle of perfume on opening evolves an odour because gases diffuse very easily and odour spreads over a large distance.
These reasons help us understand the physical behavior of particles in different states. By observing properties like solubility or diffusion, we can scientifically identify different substances.
Teacher's Tip: Use the perfume example to remember that gas particles are always on the move!
Exam Tip: For "Give reasons" questions, always link the physical observation back to the molecular arrangement.

Question 12: Complete the statements given below by selecting the correct word/s.
(a) Solids and liquids have a definite but ____ gases do not. [mass, shape, volume]
(b) The space between atoms in is maximum while in ____ is minimum, [solids, liquids, gases]
(c) Conversation of a vapour into a liquid is called ____ . [vaporization, condensation, freezing]
(d) ____ is an example of a crystalline substance . [wax, sugar, tea]

Answer:
(a) Solids and liquids have a definite volume but gases do not.
(b) The space between atoms in gases is maximum while in solids is minimum.
(c) Conversation of a vapour into a liquid is called condensation.
(d) Wax, sugar is an example of a crystalline substance.
These sentences summarize the fundamental differences in how matter is built. Filling in the blanks helps you check if you understand the core concepts of volume, spaces, and phase changes.
Teacher's Tip: "Condensation" always involves gas turning back into a liquid.
Exam Tip: Be careful with "volume" and "shape" as they are often mixed up; remember liquids have definite volume but NO definite shape.

Question 13: State which of the following statements are false. If false write the correct statement.

(a) Solids are highly compressible and rigid.
Answer: True.

(b) Atoms/molecules in gases move only about their own positions.
Answer: False. Atoms/molecules in gases move every where.

(c) The conversion of water to ice is called freezing.
Answer: True.
Correcting these statements ensures that you haven't misunderstood the basics of how particles move. Knowing that gas molecules "move everywhere" is essential for understanding concepts like pressure and diffusion.
Teacher's Tip: Rigid things usually don't squeeze (compress)!
Exam Tip: When a statement is false, you must write the correct fact to get full credit.

Objective Type Questions

Question 1: Fill in the blanks with the correct word/s from the bracket.
1. From the three states of matter, solids expand the least.
2. Brownian movement is maximum in gases.
3. Cohesive forces are negligible in gases.
4. Matter can change from one state to another by change in temperature or pressure.
5. The space between atoms [molecules] of solids is minimum.
6. Intermingling of molecules is called diffusion.
7. Ice on absorption of heat converts to ‘X’ a process called melting. ‘X’ changes to water vapour on heating. Water vapour changes back to ‘X’ on condensation. The constant temperature at which ice changes into ‘X’ is called its fusion point.

Question 2: State which of the following are physical properties of a substance.

1. Chlorine gas has a – strong irritating odour.
Answer: Physical.

2. Sodium nitrate is soluble in water, but calcium carbonate is not.
Answer: Physical.

3. Magnesium reacts with dilute hydrochloric acid, liberating hydrogen gas.
Answer: Chemical.

4. Manganese dioxide, a catalyst which alters the rate of a chemical reaction is black in colour.
Answer: Chemical.

5. The melting point of ice is $0^{\circ}C$.
Answer: Physical.

6. Lead chloride reacts with barium sulphate to give a white precipitate of lead sulphate.
Answer: Chemical.

7. Water acidified with dilute sulphuric acid is a good conductor of electricity.
Answer: Physical.

8. Naphthalene on heating directly turns into vapour.
Answer: Chemistry.

9. Hydrogen sulphide gas has a strong rotten egg odour.
Answer: Physical.

10. Sulphur is a yellow amorphous powder insoluble in water.
Answer: Physical.

Physical properties describe how something is, while chemical properties describe what it does during a reaction. Understanding these helps scientists identify unknown substances in the lab.
Teacher's Tip: Physical is like a photo, Chemical is like a video of a reaction.
Exam Tip: Look for words like "odour," "solubility," or "melting point" to quickly identify physical properties.

Question 3: Match the characteristics of the three states of matter in List I with their correct answer from List II.

List I
1. Are highly rigid and have a definite shape
2. Have no definite shape
3. Have a definite volume but no definite shape
4. Are highly compressible and least rigid
5. Have no definite volume
6. Have no definite shape and volume
7. Occupy space
8. Are not compressible
9. Are slightly compressible
10. Have mass

List II
A : Solids and gases only
B : Solids only
C : Liquids and gases only
D : Gases only
E : Solids, liquids and gases
F : Liquids only
G : Solids and liquids only

Answer:
1. Are highly rigid and have a definite shape - B : Solids only
2. Have no definite shape - C : Liquids and gases only
3. Have a definite volume but no definite shape - F : Liquids only
4. Are highly compressible and least rigid - D : Gases only
5. Have no definite volume - D : Gases only
6. Have no definite shape and volume - D : Gases only
7. Occupy space - E : Solids, liquids and gases
8. Are not compressible - B : Solids only
9. Are slightly compressible - F : Liquids only
10. Have mass - E : Solids, liquids and gases
These characteristics describe how the internal arrangement of molecules defines the physical state of matter. By identifying which properties like shape and volume are fixed or flexible, we can correctly classify any substance as a solid, liquid, or gas.
Teacher's Tip: Remember that "Mass" and "Occupying space" are the two basic requirements for anything to be called matter, so they apply to all three states!
Exam Tip: When matching properties like "no definite shape," be careful to include both liquids and gases, as they are both fluids that take the shape of their container.

Question 4: Match the arrangement of atoms in the three states of matter in List I with the correct state in List II.
List I
1. Arrangement of atoms is far apart
2. Force of attraction between atoms is very strong
3. Movement of atoms is in any random direction
4. Particles diffuse very easily
5. Particles show movement about their own position

List II
A : Solids
B : Liquids
C : Gases

Answer:
1. Arrangement of atoms is far apart - C : Gases
2. Force of attraction between atoms is very strong - A : Solids
3. Movement of atoms is in any random direction - C : Gases
4. Particles diffuse very easily - C : Gases
5. Particles show movement about their own position - A : Solids
The way particles are arranged determines how a substance behaves, like why a solid stays still and a gas fills the room. Solids have particles locked in place by strong forces, while gas particles are free to zip around in any direction.
Teacher's Tip: Imagine solid particles are like people in a crowded elevator, while gas particles are like runners in a wide-open field.
Exam Tip: If a characteristic mentions "random" or "far apart," it almost always refers to the gaseous state.

Question 5: State the correct term from A, B, C, D, E or F in List II which represents the change of state of matter or its relevant property from List I.
List I
1. Solid 'X' to a Liquid 'Y'
2. Liquid 'Y' to its vapour 'Z'
3. 'Z' to 'Y'
4. 'Y' to 'X'
5. The temperature at which 'Y' changes to 'Z'

List II
A : Condensation
B : Vaporization
C : Melting
D : Freezing
E : Melting point
F : Boiling point

Answer:
1. Solid 'X' to a Liquid 'Y' - C : Melting
2. Liquid 'Y' to its vapour 'Z' - B : Vaporization
3. 'Z' to 'Y' - A : Condensation
4. 'Y' to 'X' - D : Freezing
5. The temperature at which 'Y' changes to 'Z' - F : Boiling point
These terms describe how matter switches between its three main states when heat is added or removed. Knowing the exact name for each phase change is a fundamental part of understanding thermodynamic processes in chemistry.
Teacher's Tip: Think of the 'V' in Vaporization as the 'V' in 'Vanishing' into the air as gas.
Exam Tip: Always double-check if the question is asking for the "process" (like melting) or the "temperature" (like melting point) to avoid easy mistakes.