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Ch.1- Matter in our surroundings 9th Solved Question

Q.1 Define matter.

Ans: Anything that occupies space and has mass and is felt by senses is called matter.Q.2 what happens if you put copper sulphate crystals in water?Ans: Copper sulphate crystals mixed between the spaces of moleculesof waterand disappear.Q.3 A substance has a definite volume but no definite shape? State whether this substance is a solid, a liquid or a gas.

Ans: LiguidQ.4 Arrange the following substances in increasing order of force of attraction between the particles.(a) Milk (b) Salt (c) Oxygen.Ans: Oxygen < Milk< SaltQ.5 A substance has neither a fixed shape nor a fixed volume . State whether it is a solid , a liquid or a gas.Ans: GasQ.6 The melting point of a substance is below the roomtemperature. Predict its physical state.Ans: IceQ.7 What is vapour ?Ans: A substance that found n gaseous state only at roomtemperatureis called VapourQ.8 Name thetemperatureat which the solid and liquid states of substance can exist together.Ans;0 degreeCQ.9What is the effect ofpressureonboiling point?Ans:boiling point increases with increase inpressure.Q.10 Name any two substances which sublime.Ans: Camphor and Naphthalene, iodine and Ammonium chloride iodineQ.11 Define Condensation.Ans:The changeof solid state from liquid state on cooling is also known as Condensation.Q.12 For any substance, why does thetemperatureremain constant duringthe changeof state?Ans: On increasing thetemperatureof solids, the kinetic energy of the particles increases which is used to overcome the forces of attraction between the particles therefore thetemperatureremain constant duringthe changeof state.Q.13 Which is the slow process , Evaporation or Boiling ?Ans: EvaporationQ.14 State the effect of surface area on rate of evaporation.Ans: If the surface area is increased, the rate of evaporation increases.Q.15 Why are we able to siphot teafaster from saucer rather than from a cup?Ans: This is because the rate of evaporation is faster from saucer.Q.16 What is the SI unit oftemperature?Ans: KelvinQ.17 Kelvin scale oftemperatureis regarded as better scale than Celsius. Why?Ans: As it has wide range of measurement and Kelvin scale oftemperaturehas always positive sign , hence regarded as better scale than Celsius.Q.18. Convert 10oC into Kelvin scale.Ans: 270 + 10 = 280 KQ.19Pressureon the surface of a gas is increased. What will happen to the inter particle forces?Ans: come closer and compressedQ.20 A gas can exertpressureon the walls of the container. Assign reason.Ans: As its partials move rapidly due to high kinetic energy.CBSE Chemistry IX Matter in our surrounding Chemistry solved questions

Q.1 Camphor disapperars withoutleavingany residue. Explain?Ans. Camphor disappears withoutleavingany residue because of sublimation, as it changes its statedirectly 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 thetemperatureof ice is 0 deg C and our bodys temp is higher than 0 deg C.Q.3 Convert the following:-a) 573 KAns. 573-273= 300 deg Cb) 36 deg CAns. 273+36 = 309 Kc) 373 deg CAns. 373+273= 646 KQ.4 Both the process of evaporation and boiling involvesthe changeof state from liquid to gas but stillthey are different from each other. Justify.Ans. Evaporation is diffeent from boiling as evaporation isa naturalphenomenon, occurs on the surfaceof the water and also it is a slow process whereas boiling is an artificialphenomenon, it occurs in the bulkof the liquid and is a fast process.Q.5 Why is Kelvin considered as the best scale for measuring thetemperature?Ans. Kelvin is the best scale for measuring thetemperaturebecause it has no max temp. and it canmeasuretemperatureto 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 becausethe action absorbs kinetic energy from our hand & evaporates and evaporation causes cooling.Q.7 What is the significance ofboiling point& melting point of a substance?Ans. The significance ofboiling pointand melting point is that it shows the purity of the substance.Q.8 When we put CuSO4 in water, after sometime wefind thesoln. 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 thattableis a solid?Ans. When we apply force on thetableit doesnt change its shape because its intermolecules are tightlypacked , this shows thattableis solid.Q.10 Arrange the following in decreasing order of force of attraction: Water, Salt, Oxygen,Also, state the reason.Ans. Salt, Water, OxygenSalt has the maximum force of attraction as it is a solid, followed by water as it is a liquid. Oxygenis a gas so its force of attraction is the least.Q. 11 State characteristics of matter demonstrated by :a) diffusionAns. Diffusion involves movement of different particles so that they become intermixed uniformly .b) Brownian motionAns.It is thwe 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 thewhole room quickly.Which characteristic of the particles of matter is illustrated by this observation?Ans. Particles of matter are constantly moving.Q.13 Theboiling pointof alcohol isn 78 deg C. What is thistemperatureon Kelvin scale?Ans. K= Deg C + 273 = 78 + 273 = 351 KQ. 14 The Kelvin scaletemperatureis 0 K. What is the corresponding Celsius scaletemperature?Ans. 273 deg CQ. 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 1kilogram of the solid (at its melting point ) to liquid, without any change intemperature.Q. 16 Define latent heat of Vaporisation?Ans. The latent heatm of vaporisation of a liquid is the quantity of heat in joules required to convert 1kilogram of the liquid (at itsboiling point) to vapour or gas, without any change intemperature.

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 thekitchensin our homes in the-

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

3. Which of the following is not fluid - a. water, b. air, c. sand, d. sharbat?

4. On Kelvin scale 0oC is equal to a. 273 K b. -273 K c. 0 K d. 100 K

5. SI unit oftemperatureis - a. Kelvin b. Celsius c. Fahrenheit d. Pascal6. Dry ice means a. solid SO2 b. solid water c. solid CO2 d. solid CO

7. Condensation is a process which involvesconversionof

a. solid into liquid b. liquid into vapour c. vapour into liquid d. liquid into solid

8. During evaporation, theparticles ofliquid evaporate from

a. The bulk of liquid b. surface only c.the surfaceand bulk of liquid d. none of them.

9. Which of the following will not sublime

a. Camphor b. ammonium chloride c. bromine d. iodine?

10. A state of matter which has a definite shape and fixed volume

a. Solid b. liquid c. gas d. none of these.

11. A state of matter which does not have a definite shape but has definite volume

a. Solid b. liquid c. gas d. none of these.

12. A state of matter which neither has neither definite shape nor definite volume

a. Solid b. liquid c. gas d. none of these.

13. The states of matter can be changed by changing

a.Temperatureb.pressurec. both (a) and (b) d. none of these.

14. The rate of evaporation does not depend on

a.Temperatureb. humidity c.pressured. speed of wind.

15. Which of the following is accompanied by cooling

a. Vaporization b. evaporation c. condensation d. none of these.

16. A bulk phenomenon in which particles from whole of the liquid change into vapour state is called -

a. Boiling b. cooling c. melting d. none of these.

17. The amount of heat energy required to change 1 kg of solid into liquid at its melting point is called

a. Melting point b. latent heat of fusion c. boiling point d. latent heat of vaporization.

18. The amount of heat energy required to change 1 kg of liquid into solidat its boiling point is called a. Melting point b. latent heat of fusion c. boiling point d. latent heat of vaporization.

19. The densityof wateris _________ than that of ice. a. More b. less c. equal to d. none.

20. Thetemperatureat which the solid melts to become a liquid at the atmosphericpressureis called

a. Boiling point b. melting point c. freezing point d. none of these.

21. Thetemperatureat which the vapourpressureof the liquid becomes equal to the atmosphericpressureis called

a. Boiling point b. melting point c. freezing point d. none of these.

22. Which is not the characteristic of matter

a.particles ofa matter are continuously moving,

b.particles ofmatter move faster on increasingtemperature,

c.particles ofmatter intermix with each other on their own,

d.Particles ofall maters have same kinetic energy.

23. The compressibility of which state of matter is high

a. Solid b. liquid c. gas d. all of these.

24. Which of the following is the simplest form of matter

a. Element b. mixture c. compound d. none of these.

25. Which of them is most energetic

a. Solids b. liquids c. gases d. all of them.

26. Which of the following is correct for something to be called matter -

a. It should occupy spaceb. It should have mass c. Both (a) and (b) d. None of these.

27. Which of the following cannot be considered as matter

a. Mixture b. affection c. gas d. liquid.

28. Which of the following is correct about solid carbon dioxide

a. It is used in theatres to give special effects.

b. It is extremely cold substance.

c. It is used to keep freeze food and to keep ice-cream cold.

d. All of them.

e. Noneof them.

29. Which of the following statements is not correct

a. The density of ice is less than the densityof water.

b. To convert atemperatureon the Kelvin scale to Celsius scale, subtract 273 from the giventemperature.

c. To convert atemperatureon the Celsius scale to Kelvinscale, add 273 to the giventemperature.

d. Vaporisation of a liquid causes cooling.

30. When a substance is directly changed form solid state to gas on heating or from gas to solid on cooling, this process is called

a. Evaporation b. condensation c. sublimation d. vaporization

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-dimensionalconceptof 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 fundamentalconceptin physics, roughly corresponding to the intuitive idea of "how much matter there is in an object". Mass is a centralconceptofclassical mechanicsand related subjects, and there are severaldefinitionsof mass within the framework of relativistic kinematics (see mass in special relativity and mass in General Relativity). In the theory of relativity, thequantityinvariant mass, which inconceptis 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 aquantitythat measures the ratio of an evolution to time. Example: speed of sedimentation, speed of economic growth, speed ofchemical reactionetc.

Melting point:The melting point of a crystalline solid is thetemperaturerange at which it changes state from solid to liquid. Although the phrase would suggest a specifictemperatureand is commonly and incorrectly used as such in mosttextbooksand literature, most crystallinecompoundsactually 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 thetemperatureof the reverse change from liquid to solid, it is referred to as the freezing point.

Atmospheric pressure:Atmospheric pressureis the pressure at any point in the Earth's atmosphere. In most circumstancesatmospheric pressureis 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 m (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.Matter in our surrounding notes for class 9th

Matter in our surrounding Explanatory notesIntroduction:Everything in this universe is made up of material which scientists have named matter. The air we breathe,the foodwe eat, stones, clouds, stars,plants and animals, even a small dropof wateror a particle of sand each thing is matter.Early Indian philosophers classified matter inthe formof 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 ofParticles ofMatter1.PARTICLES OFMATTER HAVE SPACE BETWEEN THEM- when we make tea, coffee or lemonade (nimbu paani ),particles ofone type of matter get into the spaces betweenparticles ofthe other. This showsthat thereis enough space betweenparticles ofmatter. Similarlyparticles ofsugar, salt, Dettol, or potassium permanganate get evenly distributed in water.2.PARTICLES OFMATTER ARE CONTINUOUSLY MOVING-Particles ofmatter are continuously moving, that is, they possesswhat wecall the kinetic energy. As thetemperaturerises, particles move faster. So, we can say that with increase intemperaturethe kinetic energy of the particles alsoincreases.3.PARTICLES OFMATTER ATTRACT EACH OTHER-Particles ofmatter 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 Matter1. THESOLIDSTATE-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. THELIQUIDSTATE-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 StateWater can exist in three states of matterSolid, as ice,Liquid, as the familiar water, andGas, as water vapour.EFFECT OF CHANGE OFTEMPERATUREOn increasing the temperature of solids, the kinetic energy of the particlesincreases. 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