CBSE TEST PAPER Chapter : Matter in Our Surroundings

CBSE TEST PAPER  Chapter : Matter in Our Surroundings

1. State whether True or False. (i) Water has no definite shape; therefore, it is not matter. (ii) Gases expand to fill the space available.

2. A substance has a definite volume, but no definite shape. State whether this substance is solid, liquid or gas.

3. Which physical state of matter is the densest?

4.What are the different factors affecting evaporation?

5.Give two reasons as to why a block of ice is considered as matter.

6. Why does matter change state?

7. It is observed that water boils at lower temperature at higher altitudes. Why?

8. If some alcohol is rubbed on the hand, the rubbed portion of the hand feels cool. Why?

9. Name the following. (i) State of matter having the maximum intermolecular space (ii) Force between particles of matter (iii) State of matter with only one free surface

10. A large crystal of potassium permanganate is kept in a glass beaker containing water. This setup is then left undisturbed for an hour. The solution undergoes a change in colour.

(i) What is this change in colour?(ii) Why does such a change take place?

Chemistry Guess Questions Banks :Matter in Our Surroundings

Chemistry Adda Class IX, Chemistry  Guess Questions Banks

Chapter 1: Matter in Our Surroundings

1.      What are the different states of matter? Why do matter exist in these different states? [2]

2.      Why is ice at 273k is more effective in cooling than water at same temperature? [2]

3.      Give reasons. a. Naphthalene balls disappear with time without leaving any residue.

4.      b. We can get the smell of perfume sitting several meters away [2]

5.      What is the physical state of water at a)30oC b)0oC c)100oC

6.      What type of clothes should we wear in summer? [2]

7.      How does the water kept in an earthen pot (matka) become cool during summer? [2]

8.      Why are we able to sip hot tea or milk faster from a saucer rather than a cup? [2]

9.      Why does a desert cooler cool better on a hot dry day? [2]

10.  For any substance, why does the temperature remain constant during its phase change?[2]

11.  What is sublimation? [2]

12.  Give reasons for - [3] The smell of hot sizzling food reaches you several meters away, but to get the smell from cold food you have to go close.

13.  Give reasons for : How does evaporation cause cooling? [3]

14.  Explain giving an activity that the liquids differ in their relative diffusion rates [3]

15.  Differentiate between evaporation & boiling. [3]

16.  Give two reasons to justify. (a) Water at room temperature is a liquid (b) An iron almirah is a solid at room temperature. [3]

17.  Give reasons- [3]

(A) A gas fills completely the vessel in which it is kept.

(B) A gas exerts pressure on the walls of the container.

(C) A wooden table should be called a solid.

18.  What are the characteristics of the particles of matter? [3]

19.  A diver is able to cut through water in a swimming pool. Which property of matter does this observation prove? [3]

20.  What will happen if we put an animal cell or a plant cell into a solution of sugar or salt in water? [3]

21.  Define the following terms.

Fusion, latent heat of fusion, boiling point, latent heat of vaporization and sublimation. [3]

IX Matter in Our Surroundings Assignment

1. A substance has a definite volume but no definite shape. State whether this substance is a solid, liquid or a gas.

2. Why do solids not diffuse into one another?

3. What is matter? How is it classified?

4. How will you show that air has maximum compressibility?

5) Matter has ___________.

1.  no mass but occupies space     2. mass but occupies no space 3. mass and occupies space          4.no mass and occupies no space

6. Among solids, liquids and gases which one has the maximum movement of molecules, the maximum inter molecular attraction and the minimum space between molecules.

7.  List two properties that liquids have in common with gases.

8. What happens when a liquid is heated?

9. Why does water boil at a lower temperature at higher altitudes?

Define latent heat of fusion and vapourization?

10.  A solid that sublimes on heating is _________.

1. sodium chloride         2. copper sulphate    3. lead sulphate  4. ammonium chloride

11. Why does a desert cooler cool on a hot dry day?

12. What is difference between evaporation and boiling?

13. A sponge can be pressed easily; still it is called a solid. Why?

14. Why water vapour does have more energy than water at same temperature?

15. In gases, particles vibrate _________.

1. about their mean position 2. about a vertical axis  3. about a horizontal axis   4.in any direction

CBSE Chemistry IX Matter in our surrounding Chemistry solved questions

Q.1 Camphor disapperars without leaving any residue. Explain?

Ans. Camphor disappears without leaving any residue because of sublimation, as it changes its state directly from solid to gas without changing to liquid.

Q.2 Why do we feel cool when we touch a piece of ice?

Ans. We feel cool because the temperature of ice is 0 deg C and our body’s temp is higher than 0 deg C.

Q.3 Convert the following:-  (a) 573 K  (b) 36 deg C  (c) 373 deg C

Ans. 573-273    = 300 deg C
b) 36 deg C      =  273+36 = 309 K
c) 373 deg C     = 373+273= 646 K

Q.4 Both the process of evaporation and boiling involves the change of state from liquid to gas but still they are different from each other. Justify.

Ans. Evaporation is different from boiling as evaporation is a natural phenomenon, occurs on the surface of the water and also it is a slow process whereas boiling is an artificial phenomenon , it occurs in the bulk of the liquid and is a fast process.

Q.5 Why is Kelvin considered as the best scale for measuring the temperature?

Ans. Kelvin is the best scale for measuring the temperature because it has no max temp. and it can
measure temperature to any extent.

Q.6 How can you show that evaporation causes cooling?

Ans. When we put some acetone on our hand , after sometime we will feel coolness on our hand because the action absorbs kinetic energy from our hand & evaporates and evaporation causes cooling.

Q.7 What is the significance of boiling point & melting point of a substance?

Ans. The significance of boiling point and melting point is that it shows the purity of the substance.

Q.8 When we put CuSO4 in water, after sometime we find the soln. turns blue. Why? Also, on heating it, what change will occur?

Ans. The solution turns blue because of diffusion. On heating the solution nothing will happen

Q.9 How can you justify that table is a solid?

Ans. When we apply force on the table it doesn’t change its shape because its inter molecules are  tightly packed , this shows that table is solid.

Q.10 Arrange the following in decreasing order of force of attraction: Water, Salt, Oxygen,

Also, state the reason.

Ans. Salt, Water, Oxygen

Salt has the maximum force of attraction as it is a solid, followed by water as it is a liquid. Oxygen is a gas so its force of attraction is the least.

Q. 11 State characteristics of matter demonstrated by : (a) diffusion  (b) Brownian motion

Ans. (a) Diffusion involves movement of different particles so that they become intermixed 

uniformly .

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

Q.12 When an incense stick (agarbatti) 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.

Q.13 The boiling point of alcohol is 78 deg C. What is this temperature on Kelvin scale?

Ans. K= Deg C + 273 = 78 + 273 = 351 K

Q. 14 The Kelvin scale temperature is 0 K. What is the corresponding Celsius scale temperature?

Ans. – 273 deg C

Q. 15 What is Latent Heat of Fusion?

Ans. The latent heat of fusion (or melting) of a solid is the quanity of heat in joules required to convert 1 kilogram of the solid (at its melting point ) to liquid, without any change in temperature.

Q. 16 Define latent heat of Vaporization?

Ans. The latent heat of vaporisation of a liquid is the quantity of heat in joules required to convert  1 kilogram of the liquid (at its boiling point ) to vapour or gas, without any change in temperature.

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MCQ 9th science Matter In Our Surroundings MCQ

1. Camphor is purified by the process of –

a. evaporation b. distillation c. sublimation d. filtration

2. LPG is used in the kitchens in our homes in the-

a. Solid form b. compressed form c. gaseous form d. none.

Matter In Our Surroundings MCQ

MATER IN OUR SURONDING DEFINATIONS

Matter:
matter is commonly defined as the substance of which physical objects are composed, not counting the contribution of various energy or force-fields, which are not usually considered to be matter per se (though they may contribute to the mass of objects). Matter constitutes much of the observable universe, although again, light is not ordinarily considered matter. Unfortunately, for scientific purposes, "matter" is somewhat loosely defined. It can also be defined as a physical substance that has mass and volume.

Volume:
The volume of a solid object is the three-dimensional concept of how much space it occupies, often quantified numerically. One-dimensional figures (such as lines) and two-dimensional shapes (such as squares) are assigned zero volume in the three-dimensional space.
Mass:
Mass is a fundamental concept in physics, roughly corresponding to the intuitive idea of "how much matter there is in an object". Mass is a central concept of classical mechanics and related subjects, and there are several definitions of mass within the framework of relativistic kinematics (see mass in special relativity and mass in General Relativity). In the theory of relativity, the quantity invariant mass, which in concept is close to the classical idea of mass, does not vary between single observers in different reference frames

Diffusion:
In the second sense of diffusion is the spontaneous net movement of particles from an area of high concentration to an area of low concentration through a semi-permeable membrane. For example, diffusing molecules will move randomly between areas of high and low concentration but because there are more molecules in the high concentration region, more molecules will leave the high concentration region than the low concentration one. Therefore, there will be a net movement of molecules from high to low concentration. Initially, a concentration gradient leaves a smooth decrease in concentration from high to low which will form between the two regions. As time progresses, the gradient will grow increasingly shallow until the concentrations are equalized.

Force:
force is what causes a mass to accelerate. It may be experienced as a lift, a push, or a pull. The acceleration of the body is proportional to the vector sum of all forces acting on it (known as net force or resultant force). In an extended body, force may also cause rotation, deformation, or an increase in pressure for the body. Rotational effects are determined by the torques, while deformation and pressure are determined by the stresses that the forces create.

Pressure:
Pressure is the force per unit area applied on a surface in a direction perpendicular to that surface.

Density:
density is mass (m) per unit volume (V) — the ratio of the amount of matter in an object compared to its volume. A small, heavy object, such as a rock or a lump of lead, is denser than a larger object of the same mass, such as a piece of cork or foam.

Kinetic energy: The kinetic energy of an object is the extra energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its current velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. Negative work of the same magnitude would be required to return the body to a state of rest from that velocity.

Speed:
speed is a quantity that measures the ratio of an evolution to time. Example: speed of sedimentation, speed of economic growth, speed of chemical reaction etc.

Melting point:
The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. Although the phrase would suggest a specific temperature and is commonly and incorrectly used as such in most textbooks and literature, most crystalline compounds actually melt over a range of a few degrees or less. At the melting point the solid and liquid phase exist in equilibrium. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point.

Atmospheric pressure:

Atmospheric pressure is the pressure at any point in the Earth's atmosphere. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location. Similarly, as elevation increases there is less overlying atmospheric mass, so that pressure decreases with increasing elevation. A column of air 1 square inch in cross section, measured from sea level to the top of the atmosphere, would weigh approximately 14.7 lbf. A 1 m² (11 sq ft) column of air would weigh about 100 kilonewtons (equivalent to a mass of 10.2 tonnes at the surface).


Latent heat:

Latent heat is the amount of energy in the form of heat released or absorbed by a substance during a change of phase (i.e. solid, liquid, or gas), - also called a phase transition.

Vaporisation:

Evaporation is the process by which molecules in a liquid state (e.g. water) spontaneously become gaseous (e.g. water vapor). It is the opposite of condensation. Generally, evaporation can be seen by the gradual disappearance of a liquid, when exposed to a significant volume of gas.
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Matter in our surrounding notes for class 9th

Matter in our surrounding Explanatory notes

Introduction: 
Everything in this universe is made up of material which scientists have named “matter”. The air we breathe, the food we eat, stones, clouds, stars, plants and animals, even a small drop of water or a particle of sand– each thing is matter.

Early Indian philosophers classified matter in the form of five basic elements –air, earth, fire, sky and water.

Modern day scientists have evolved two types of classification of matter based on their physical properties and chemical nature.

Characteristics of Particles of Matter

1. PARTICLES OF MATTER HAVE SPACE BETWEEN THEM- when we make tea, coffee or lemonade (nimbu paani ), particles of one type of matter get into the spaces between particles of the other. This shows that there is enough space between particles of matter. Similarly particles of sugar, salt, Dettol, or potassium permanganate get evenly distributed in water.

2. PARTICLES OF MATTER ARE CONTINUOUSLY MOVING- Particles of matter are continuously moving, that is, they possess what we call the kinetic energy. As the temperature rises, particles move faster. So, we can say that with increase in temperature the kinetic energy of the particles also increases.

3. PARTICLES OF MATTER ATTRACT EACH OTHER- Particles of matter have force acting between them. This force keeps the particles together. The strength of this force of attraction varies from one kind of matter to another.

States of Matter

1. THE SOLID STATE- all solids have a definite shape, distinct boundaries and fixed volumes, that is, have negligible compressibility. Solids have a tendency to maintain their shape when subjected to outside force. Solids may break under force but it is difficult to change their shape, so they are rigid.

2. THE LIQUID STATE- Liquids have no fixed shape but have a fixed volume. They take up the shape of the container in which they are kept. Liquids flow and change shape, so they are not rigid but can be called fluid. The rate of diffusion of liquids is higher than that of solids. This is due to the fact that in the liquid state, particles move freely and have greater space between each other as compared to particles in the solid state.

3. THE GASEOUS STATE- Gases are highly compressible as compared to solids and liquids. The liquefied petroleum gas (LPG) cylinder that we get in our home for cooking or the oxygen supplied to hospitals in cylinders is compressed gas. In the gaseous state, the particles move about randomly at high speed. Due to this random movement, the particles hit each other and also the walls of the container.

Matter Can Change its State Water can exist in three states of matter–

·  Solid, as ice,

·  Liquid, as the familiar water, and

·  Gas, as water vapour.

EFFECT OF CHANGE OF TEMPERATURE

On increasing the temperature of solids, the kinetic energy of the particles increases. Due to the increase in kinetic energy, the particles start vibrating with greater speed. The energy supplied by heat overcomes the forces of attraction between the particles. The particles leave their fixed positions and start moving more freely. A stage is reached when the solid melts and is converted to a liquid. The temperature at which a solid melts to become a liquid at the atmospheric pressure is called its melting point.

The melting point of ice is 273.16 K. The process of melting, that is, change of solid state into liquid state is also known as fusion.

Solid ----heat----> Liquid  -------------------heat--> Gas 

          <---cool----                  <---cool---------------

So, we infer that the state of matter can be changed into another state by changing the temperature.

EFFECT OF CHANGE OF PRESSURE

Increasing or decreasing the pressure can change the state of matter. Applying pressure and reducing temperature can liquefy gases.

For an example, Solid carbon dioxide (CO2) is stored under high pressure. Solid CO2 gets converted directly to gaseous state on decrease of pressure to 1 atmosphere* without coming into liquid state. This is the reason that solid carbon dioxide is also known as dry ice.

Thus, we can say that pressure and temperature determine the state of a substance, whether it will be solid, liquid or gas.

Evaporation

Particles of matter are always moving and are never at rest. At a given temperature in any gas, liquid or solid, there are particles with different amounts of kinetic energy. In the case of liquids, a small fraction of particles at the surface, having higher kinetic energy, is able to break away from the forces of attraction of other particles and gets converted into vapour. This phenomenon of change of a liquid into vapours at any temperature below its boiling point is called evaporation.

FACTORS AFFECTING EVAPORATION

The rate of evaporation increases with–

• An increase of surface area: We know that evaporation is a surface phenomenon. If the surface area is increased, the rate of evaporation increases. For example, while putting clothes for drying up we spread them out.

• An increase of temperature: With the increase of temperature, more number of particles get enough kinetic energy to go into the vapour state.

• A decrease in humidity: Humidity is the amount of water vapour present in air. The air around us cannot hold more than a definite amount of water vapour at a given temperature. If the amount of water in air is already high, the rate of evaporation decreases.

• An increase in wind speed: It is a common observation that clothes dry faster on a windy day. With the increase in wind speed, the particles of water vapour move away with the wind, decreasing the amount of water vapour in the surrounding.

HOW DOES EVAPORATION CAUSE COOLING?

In an open vessel, the liquid keeps on evaporating. The particles of liquid absorb energy from the surrounding to regain the energy lost during evaporation. This absorption of energy from the surroundings make the surroundings cold.

After a hot sunny day, people sprinkle water on the roof or open ground because the large latent heat of vaporisation of water helps to cool the hot surface.

Why should we wear cotton clothes in summer?

During summer, we perspire more because of the mechanism of our body which keeps us cool. We know that during evaporation, the particles at the surface of the liquid gain energy from the surroundings or body surface and change into vapour. The heat energy equal to the latent heat of vaporisation is absorbed from the body leaving the body cool. Cotton, being a good absorber of water helps in absorbing the sweat and exposing it to the atmosphere for easy evaporation.

Why do we see water droplets on the outer surface of a glass containing ice-cold water?

Let us take some ice-cold water in a tumbler. Very soon we see water droplets on the outer surface of the tumbler. The water vapour present in air, on coming in contact with the cold glass of water, loses energy and gets converted to liquid state, which we see as water droplets.

Matter in Our Surroundings Top concepts

Chemistry Adda Class: IX: Chemistry Chapter 1: Matter in our Surroundings

Top concepts

1. Anything that occupies space and has mass is known as matter.

2. Matter is not continuous but rather consists of large number of particles.

3. Characteristics of Particle

a.       Large number of particles constitutes matter.

b.      Particles of matter are very small in size.

c.       Particles of matter have spaces between them

d.      Particles of matter are continuously moving

4. Solids have definite shape, distinct boundaries and fixed volume

5. Liquids have fixed volume but no fixed shape.

6. Gases neither have fixed shape nor volume.

7. Solids possess least compressibility.

8. Liquids possess higher compressibility than solids.

9. Gases possess highest compressibility as compared to solids and liquids.

10. The process in which a solid changes to liquid state by absorbing heat at constant

temperature is called fusion.

11. The temperature at which a solid melts to become a liquid at the atmospheric pressure is called as melting point.

12. SI unit of temperature is Kelvin. T (K)= T (oC) +273

13. The hidden heat which breaks the force of attraction between the molecules during  change of state is called latent heat.

14. Latent heat of fusion is the amount of heat energy required to change 1kg of solid into  liquid at its melting point.

15. The melting point of a solid is an indication of the strength of the force of attraction between its particles.

16. The temperature at which a liquid changes to solid  by giving out heat at atmospheric  pressure is called freezing point.

17. The temperature at which a liquid starts boiling at the atmospheric pressure is known as  boiling point.

18. Latent heat of vaporization is the heat energy required to change 1kg of liquid to gas at atmospheric pressure at its boiling point.

19. Boiling is a bulk phenomenon.

20. The phenomenon of change of a liquid into its gaseous state at any temperature below  its boiling point is known as evaporation.

21. In evaporation, the conversion of liquid to gaseous state occurs at a much slower rate,  compared to boiling.

22. Evaporation takes place only at the surface of the liquid while boiling can take place in  all parts of the liquid.

23. Evaporation is surface phenomenon

24. Boiling is a bulk phenomena

25. The amount of water vapour present in the air is called humidity.

26. Evaporation is a continuous or ongoing process.

27. Evaporation causes cooling.

28. The process of evaporation of water from the aerial parts of plants  especially leaves is  known as transpiration.

29. The rate of evaporation is affected by the surface  area exposed to atmosphere, temperature, humidity and wind speed.

30. Since evaporation is a surface phenomenon, therefore, it increases with an increase in surface area

31. Evaporation increases with an increase in temperature.

32. Evaporation decreases with an increase in humidity

33. Evaporation increases with the increase in wind speed

34. The process in which a gas changes into liquid state by giving out heat at constant  temperature is called condensation.

9th Sample Guess Extra score solved paper Matter in Our Surroundings

Class IX, Chemistry Solved Questions Chapter 1: Matter in Our Surroundings

1. what are the states of Matter around us?

Ans The matter around us exists in three states— solid, liquid and gas.

2. In which state of matter there will be maximum force of attraction between particles?

Ans. The maximum forces of attraction between the particles will be in Solid state.

3. In which state of matter there will be maximum kinetic energy of the particles?

Ans The maximum kinetic energy of the particles will be in gaseous state of matter.

4.What do you mean by Sublimation

Ans Sublimation is the change of gaseous state directly to solid state without going through liquid state, and vice versa.

5. What do you mean by Latent heat of vaporization?

Ans Latent heat of vaporization is the heat energy required to change1 kg of a liquid to gas at atmospheric pressure at its boiling point.

6. What do you mean by Latent heat of fusion?

Ans Latent heat of fusion is the amount of heat energy required to change 1 kg of solid into liquid at its melting point.

7. In which unit pressure is measured?

Ans. Pascal.

8. Convert the 5730 K temperatures to the Celsius scale.

Ans 573-273=3000 Celsius.

9. What is the physical state of water a 25­­0 C?

Ans Liquid state.

10. What produces more severe burns, boiling water or steam and why?

Ans Steam as it also has energy of latent heat of vaporization.

11. What is the unit of measurement of volume?

Ans cubic metre.

12. What are the Characteristics of Particles of Matter?

Ans Particles of matter have space between them, particles of matter attract each other and particles of matter are continuously in movement.

13. Arrange the following substances in increasing order of forces of attraction between the particles— water, sugar, oxygen?

Ans Oxygen –water –sugar.

15. Why should we wear cotton clothes in summer?

Ans During summer, we perspire more. And as we know that during evaporation, the particles at the surface of the liquid gain energy from the surroundings or body surface and change into vapour. The heat energy equal to the latent heat of vaporization is absorbed from the body leaving the body cool. Cotton, being a good absorber of water helps in absorbing the sweat and exposing it to the atmosphere for easy evaporation.