9C01_Matter in Our Surroundings_Avanti Module

9C01 – Matter in Our Surroundings 1 Sixth Edition 9C01. Matter in Our Surroundings TABLE OF CONTENTS 9C01. Matter in Our Surroundings 1 9C01.1 Introduction to Matter ............................................................................................................................................................2 9C01.2 States of Matter ..........................................................................................................................................................................3 9C01.3 Change in State of Matter.......................................................................................................................................................5 9C01.4 Evaporation..................................................................................................................................................................................8 Advanced Practice Problems ..............................................................................................................................................................11 CBSE Practice Problems........................................................................................................................................................................13 Olympiad Practice Problems ..............................................................................................................................................................15

9C01 – Matter in Our Surroundings 2 9C01.1 Introduction to Matter CONCEPTS COVERED 1. Matter and its physical nature 2. Particulate nature of matter 3. Characteristics of particles of matter: I. Particles of matter are continuously moving II. Particles of matter have space between them III. Particles of matter attract each other IV. Particles of matter are very small in size. IN CLASS EXERCISE Q1. What is matter? Q2. Which of the following are matter? Chair, air, love, smell, hate, almonds, thought, cold, cold-drink, perfume Q3. Which characteristic of matter is illustrated by the following observations? I. When an incense stick (agarbatti) is lit in one corner of the room, its fragrance spreads in the entire room quickly. II. A piece of chalk can be broken into small particles by hammering but a piece of iron cannot be broken into small pieces by hammering. Q4. What do you mean by diffusion? Explain in brief with the help of an example. Q5. What happens when a crystal of potassium permanganate is dropped in a glass tumbler containing water? What conclusion can you draw from this observation? Q6. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show? HOMEWORK Q1. Which of the following are matter? I. Laptop II. Desk III. Anger IV. Sugar V. Juice VI. Smoke VII. Jealousy Q2. Why are light and sound not considered as matter? Q3. What are the characteristics of the particles of matter? Q4. Name the process by which a drop of ink spreads in a beaker of water. Define the process involved. Q5. When someone opens a bottle of perfume in one corner of a room, its smell spreads in the entire room after sometime. Why? ADVANCED QUESTIONS Q1. In severe cold weather, Mohan’s family burnt wood in the room during the night while keeping the windows closed. After sometime, they felt suffocated. Mohan immediately opened the windows and got relief. What could be the scientific reason behind this? Q2. How can we detect if there is a gas leakage in our kitchen cylinder? 9C01.1

9C01 – Matter in Our Surroundings 3 9C01.2 States of Matter CONCEPTS COVERED 1. States of matter – solid, liquid and gas 2. Characteristics and examples of different states of matter IN CLASS EXERCISE Q1. Why do three states of matter arise? Q2. Tabulate the differences in the characteristics of various states of matter. Q3. Out of the following, which matter will diffuse easily? Oxygen gas, lemonade, wooden duster Q4. In which states of matter, the arrangement of particles is in the I. Most ordered form? II. Least ordered form? Q5. Why are gases highly compressible? Q6. Arrange the following in the increasing order of density: Air, exhaust from chimneys, honey, water, chalk, cotton, iron Q7. Arrange a block of wood, water and air in increasing order on the basis of following properties: I. Compressibility II. Motion of particles III. Rigidity Q8. Give an example of a I. Liquid diffusing into a solid II. Solid diffusing into a liquid III. Solid diffusing into a solid Q9. Why do gases exert more pressure on the walls of the container than solids? Q10. Shown below are some drawings made by some students to show the arrangement of particles in materials of different states of matter. However, they forgot to put the label for each arrangement. Match the following labels with the correct drawing: HOMEWORK Q1. Name the three states of matter. Give examples of each of these states. Q2. Why can’t a gas cylinder be half-filled? Q3. Why can’t we compress solids? Q4. Why is the rate of diffusion faster in gases? 9C01.2

9C01 – Matter in Our Surroundings 4 Q5. Give one similarity and one dissimilarity between a liquid and a gas. Q6. Briefly explain the term density. Q7. Define the following: I. Rigidity II. Fluidity Q8. Give an explanation for each of the following statements: I. Water and air both take the shape of the container but one of them is a liquid and another is a gas. II. A rubber band changes its shape on being stretched but is still considered a solid. Q9. Arrange iron nail, kerosene, oxygen in the increasing order of: I. Force of attraction between particles II. Space between particles Q10. How do aquatic animals breathe underwater? Q11. Why are liquids and gases called fluids? Q12. Are ice and water essentially the same substance, chemically? Give reasons for your answer. Q13. Why do solids and liquids have open surface while gases do not? ADVANCED QUESTIONS Q1. The density of a substance is defined as mass per unit volume. However, it is often convenient to express density of a substance in comparison with that of water. The relative density of a substance is the ratio of its density to that of water: Relative density = ������������������������������������������ ������������ ������ ������������������������������������������������������ ������������������������������������������ ������������ ������������������������������ Since the relative density is a ratio of similar quantities, it has no unit. Based on this information, answer the following question: What, according to you, will be the typical relative density of solids? A) < 1 B) > 1 C) = 1 D) Can be any of the above, depending on the substance Q2. It is not proper to regard the gaseous state of ammonia as vapors. Explain in brief. Q3. Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. What according to you is the reason for this? 9C01.2

9C01 – Matter in Our Surroundings 5 9C01.3 Change in State of Matter CONCEPTS COVERED 1. Temperature 2. Kinetic energy 3. Conversion of substances from one state of matter to another – role of temperature and pressure in I. Solidification II. Fusion III. Sublimation IV. Vaporisation V. Condensation IN CLASS EXERCISE Q1. Convert the following temperature from Kelvin to Celsius (℃) scale I. 300 ������ II. 573 ������ Q2. Define the following terms: I. Solidification II. Condensation III. Melting IV. Temperature Q3. Explain why, naphthalene balls kept in stored clothes in our homes disappear over a period of time. Q4. The following triangle exhibits inter-conversion of the three states of matter. Complete the triangle by labelling the arrows marked ������, ������, ������ & ������. Q5. Which phenomenon occurs during the following changes? I. Formation of clouds II. Drying of wet clothes III. Wax melts in the sun IV. Size of naphthalene balls decreases Q6. Give reason for the following observation: “The smell of hot food reaches us several metres away, but to get the smell of cold food we have to go close”. Q7. Define: I. Latent heat of fusion of water II. Latent heat of vaporization of water Q8. How does the melting point of a substance indicate the strength of its intermolecular forces of attraction? Q9. Benzene is a liquid with boiling point equal to 80℃. At this temperature, it is found that particles of benzene vapors are more energetic than particles of liquid benzene. How will you explain this observation? Q10. Water as ice has a cooling effect, whereas water as steam may cause even more severe burns. How can the same substance (chemically) show different properties? Q11. Why is ice rubbed on burned part of the skin? HOMEWORK Q1. I. Name the SI unit of temperature. II. The boiling point of water is 100℃ under normal atmospheric pressure. Convert this temperature to SI unit. 9C01.3

9C01 – Matter in Our Surroundings 6 Q2. At what temperature do solid ice and liquid water coexist? Q3. On converting 25 ℃, 38 ℃ and 66 °C to Kelvin scale, the correct sequence of temperature will be A) 298 ������, 311 ������ and 339 ������ B) 298 ������, 300 ������ and 338 ������ C) 273 ������, 278 ������ and 543 ������ D) 298 ������, 310 ������ and 338 ������ Q4. How would you show that the three states of matter are interchangeable? Q5. What would be the effect of temperature on the rate of diffusion of liquids? Q6. Define ‘melting point’ of a substance. What is the melting point of ice? Q7. Define ‘boiling point’ of a substance. What is the boiling point of water? Q8. What is sublimation? Name two substances from our daily life that sublimate on heating. Q9. Select the substances which follow the process of sublimation: Ice, ammonium chloride, salt, naphthalene, ghee, coconut oil, camphor. Q10. Which of the following processes will release heat? A) Condensation B) Vaporization C) Freezing D) Melting Q11. What are the set of conditions (temperature and pressure) necessary to liquefy a gas? Q12. Compare the three states of matter in terms of force of attraction and kinetic energy of the particles. Q13. What produces more severe burns: boiling water at 100℃ or steam at 100℃? ADVANCED QUESTIONS Q1. Study the graph given below and answer the questions that follow: I. Which region contains only solid? II. Which region contains only liquid? III. Which region shows latent heat of vaporization? Q2. The temperature-time graph given below shows the heating curve for a substance: From the graph, answer the following questions: I. What is the physical state of the substance at points ������, ������, ������ and ������? II. What is the melting point of the substance? III. What is the boiling point of the substance? IV. Which portions of the graph indicate that change of state is taking place? V. Name the terms used for the absorbed heat during change of states involved in the above processes. 9C01.3

9C01 – Matter in Our Surroundings 7 Q3. A glass tumbler containing hot water is kept in the freezer compartment of a refrigerator (temperature < 0℃). If the temperature of the tumbler is measured continuously, which of the following graphs would correctly represent the change in its temperature with time? A) B) C) D) Q4. Why doesn’t dry ice wet the surface on which it is kept? 9C01.3

9C01 – Matter in Our Surroundings 8 9C01.4 Evaporation CONCEPTS COVERED 1. Evaporation 2. Difference between evaporation and boiling 3. Factors affecting evaporation 4. Evaporation causes cooling IN CLASS EXERCISE Q1. Define evaporation. Q2. Briefly discuss the factors which affect evaporation. Q3. Which one of the following sets of phenomena would increase on raising the temperature? A) Diffusion, rate of evaporation, compressibility of gases B) Rate of evaporation, compressibility of gases, solubility C) Rate of evaporation, diffusion, expansion of gases D) Rate of evaporation, solubility, diffusion, compressibility of gases Q4. How can we decrease the rate of evaporation of water from a covered beaker? Q5. How does evaporation cause cooling? Q6. How does our body maintain its temperature during summer? Q7. Why do the doctors advise to put strips of wet cloth on the forehead of a person having fever? Q8. Why is boiling called a ‘bulk phenomenon’ whereas evaporation is called a ‘surface phenomenon’? Q9. Preeti was getting late for her school. She tried to sip boiling hot milk from a cup and felt very uncomfortable. Her mother immediately brought a plate and asked her to sip milk from the plate. Preeti did the same and did not face any problem. Why did sipping the milk from a plate seem easier than sipping it from a cup? Q10. Solve the crossword using the hints given below: Hints: Across 2. Change of state directly from solid to gas 3. The 'fluid' state of matter having definite volume 10. Conversion of liquid to solid 11. The state of matter having least distance between the particles Down 1. Conversion of gas to liquid 4. Conversion of liquid to gas 5. Conversion of a solid into a liquid 6. 'Surface phenomena' 7. Matter is made up of __________ 8. SI unit of temperature 9. They take up all the space that they get! 9C01.4

9C01 – Matter in Our Surroundings 9 HOMEWORK Q1. Does evaporation lead to a physical change or a chemical change? Q2. List down the differences between boiling and evaporation. Q3. The rate of evaporation will increase in which of the following case? A) Increase in temperature, decrease in surface area B) Increase in surface area, decrease in temperature C) Increase in surface area, increase in temperature D) Decrease in temperature, decrease in surface area Q4. How does the change in temperature and humidity affect the rate of evaporation? Q5. Heat becomes unbearable in summer especially after rain. What is the reason for this? Q6. Why should we wear cotton clothes in summer? Q7. How does the water kept in an earthen pot (matka) become cool during summer? Q8. Why should wet clothes be spread while drying? Q9. Why do we see water droplets on the outer surface of a glass containing ice-cold water? 9C01.4

9C01 – Matter in Our Surroundings 10 Q10. Fill in the blanks: I. Evaporation of a liquid at room temperature leads to __________ (cooling/heating) effect. II. At room temperature, the forces of attraction between the particles of solid substances are __________ (stronger/weaker) than those existing in the gaseous state. III. The arrangement of particles is less ordered in the __________ (solid/liquid/gaseous) state. However, there is no order in the __________ (solid/liquid/gaseous) state. IV. __________ is the change of solid state directly to gaseous state without going through the liquid state. V. The phenomenon of change of liquid into the gaseous state at any temperature below its boiling point is called __________ ADVANCED QUESTIONS Q1. Why do trees acquire more leaves during summer? Q2. Why do surgeons often spray some ether on patient’s skin before performing minor surgery? Q3. Why does a desert cooler cool better on a hot dry day? Q4. When a liquid is in a confined, closed container, an equilibrium exists between the liquid and its gaseous phase, i.e., the amount of liquid being converted to vapors is equal to the amount of vapors being converted into the liquid state. The equilibrium exists due to the fact that some of the particles in the liquid (essentially at any temperature) will always have enough energy to escape the attractive forces of the liquid particles and enter the gaseous state and vice-versa. Just like all gases, these vapors also exert some force on the container. This pressure is called vapor pressure of that substance. In terms of vapor pressure, normal boiling point is defined as: ‘The boiling point of a liquid is the temperature at which its vapor pressure is equal to the pressure of the gas above it, i.e, 1 atm.’ Based on this information, what do you think will happen to the boiling point of a liquid when atmospheric pressure decreases? 9C01.4

9C01 – Matter in Our Surroundings 11 Advanced Practice Problems Q1. Smita wanted to study the rate of diffusion of liquids. She took water in two beakers and poured a drop of honey from the side of one beaker and a drop of blue ink from the side of other beaker. What would she observe? A) Honey diffuses faster than ink B) Ink diffuses faster than honey C) Both honey and ink diffuse at the same rate D) Ink diffuses but honey does not diffuse in water Q2. Study the graph given below and answer the questions that follow: I. What is the physical state of matter at point 1, 3 and 5 respectively? A) 1-Solid, 3- Liquid, 5-Gas B) 1-Solid, 3-Gas, 5-Liquid C) 1-Liquid, 3-Gas, 5-Solid D) 1-Liquid, 3-Solid, 5-Gas II. What is represented by straight lines ������������ and ������������ in the graph? A) Temperature remains same during the change of state B) ������������ represents latent heat of fusion, while ������������ represents latent heat of vaporization C) At ������������, both solid and liquid state co-exist, while at ������������ both liquid and gaseous state co-exist D) All of these Q3. The three most commonly studied states of matter are solids, liquids and gases – all these are made up of small particles called atoms. Atoms, however, are themselves made up of electrons (negatively charged), protons (positively charged) and neutrons (neutral, no charge). Normally, the electrons in a solid, liquid, or gaseous sample of matter stay with their respective atoms. But in a fourth state of matter – called the plasma, many of the electrons wander around freely. A plasma can be created by heating a gas, which decreases or increases the number of electrons. Our sun, the stars that we can see, and even regions of interstellar dust, all consist of plasma. Scientists have even been talking of a fifth state of matter – the Bose – Einstein condensate. The BEC is formed by cooling a gas of extremely low density, about one-hundred-thousandth the density of normal air, to super low temperatures. The BEC happens at super low temperatures – at zero Kelvin (absolute zero), where all molecular motion stops. Scientists have figured out a way to get a temperature only a few billionths of a degree above absolute zero. At that low temperatures, we can create a BEC with a few special elements. Based on this information, match column I with column II and select the correct option from the codes given below regarding five states of matter: A.P.P.

9C01 – Matter in Our Surroundings 12 Column I Column II a) Liquid i. Highly compressible b) Gas ii. Definite volume c) Plasma iii. Super low density d) Bose – Einstein condensate iv. Super energetic A) (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv) B) (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv) C) (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii) D) (a)-(iii), (b)-(i), (c)-(ii), (d)-(iv) Q4. Choose the correct statements about plasma state I. The state consists of super energetic and super excited particles II. The particles of plasma state are in the form of ionized gases III. The plasma can be found on stars IV. Colour of plasma glow depends on temperature of gas only A) I, II and III B) I and II C) II and III D) All of these Q5. Diagrams ������, ������ and ������ show how the particles of a substance are packed at different temperatures The given graph shows the temperature changes which occur on warming the substance. In which region of the graph would all the particles be packed as in ������? A) I B) II C) III D) IV Q6. Given figure shows the effects of pressure and temperature on the changes among three states of matter. Which of the following given statements is correct? I. Change 1 is carried out under high temperature and low pressure II. Change 4 is carried out under low temperature and high pressure III. Change 2 is carried out under low temperature and high pressure IV. Change 3 is carried out under low temperature and high pressure A) II and III B) I and II C) I, II and IV D) I, II and III Q7. The various physical properties of a substance may include A) Colour, odour and taste only B) Hardness, solubility and density only C) Melting point and boiling point only D) All of these A.P.P.

13 Avanti 9C01 Matter in Our Surroundings CBSE Practice Problems

14 Avanti 9C01 Matter in Our Surroundings CBSE Practice Problems

15 9C01 – Matter in our Surrounding – Olympiad Practice Problems INSTRUCTIONS Answer each of the following questions. 1. When liquid starts boiling, the heat energy further supplied A) Is lost to the surroundings as such B) Increases the temperature of the liquid C) Increases the kinetic energy of the particles in the liquid D) Is absorbed as latent heat of vaporization by the liquid. 2. Crystallisation technique is better than simple evaporation technique as _________. A) Some solids are evaporated with solvent B) Some solids decompose or some may get charred on heating to dryness C) Some impurities may remain dissolved in the solution even after filtration, which on evaporation contaminate the solid D) Both (B) and (C) 3. Look at the given heating curve for a pure substance carefully and answer the following question: What is the physical state of the substance at point ? A) Solid B) Gas C) Liquid D) Liquid & gas both 4. Look at the given heating curve for a pure substance carefully and answer the following question: Which points on the graph show no change is state? A) B) C) D) (A) & (C) both Avanti – 9C01 – Matter in our Surrounding – Olympiad Practice Problems ss

5. Suppose that figure 1 and 2 represent the heating curves for substances and respectively. 16 What conclusion can be drawn regarding the melting points and boiling points of substance and substance ? A) Substance has a higher melting point and a higher boiling point than substance . B) Substance has a higher melting point and a higher boiling point than substance . C) Substance has the higher melting point but substance has the higher boiling point. D) Substance has the higher melting point but substance has the higher boiling point. 6. The microscopic view of three different substances are shown in the given diagram. , and are temperatures and , and are the forces of attraction of the particles of the respective states. Choose the correct order among the following. A) < < and < < B) > > and > > C) < < and > > D) > > and < < 7. Match Column I with Column II and select the correct option from the codes given below. Column I Column II a. Drying of clothes on a windy day i. Time taken for evaporation increases b. Liquefaction of gases ii. Decreasing pressure and increasing temperature c. Change in state of dry ice from solid to gas iii. Increasing pressure and decreasing temperature d. Less cooling effect of sweating in coastal areas. iv. Rate of evaporation increases A) a – i, b – ii, c – iii, d – iv B) a – iv, b – iii, c – i, d – ii C) a – iii, b – iv, c – ii, d – i D) a – iv, b – iii, c – ii, d – i 8. Sakshi put hot water in the ice tray and kept it in the freezer compartment of a refrigerator. If she could measure the temperature of the content of the ice tray as a function of time then, which of the following graphs would correctly represent the result? A) B) Avanti – 9C01 – Matter in our Surrounding – Olympiad Practice Problems ss

C) D) 17 9. Melting and boiling points of some substances are listed in the given table : Substances Melting point (° ) Boiling point (° ) I 190 180 II 250 240 III 200 190 IV 215 182 Fill in the blanks by choosing an appropriate option. The substances which are liquid at 185° are and and the substance which is a liquid over the largest range of temperature is . A) – II, – III, – IV B) – I, – II, - III C) – I, – IV, – IV D) – I, – IV, - I 10. The melting and boiling points of few substances are given as Substances Melting point (° ) Boiling point (° ) I 180 381 II 64 759 III 0 100 IV 117 78 Following diagrams show three different states of matter at different temperatures. Out of the given substances which would exist as , and ? B) – III, – I, – IV D) – IV, – II, – I and II A) – IV, – II, – III C) – II, – IV, – I 11. Melting and boiling points of elements , , and are given in the table. Element Melting point (° ) Boiling point (° ) 189 186 219 183 7 58 20 222 Which of the following statements is/are correct? I. Elements and are liquids at room temperature. II. Element exists as a liquid while element exists as a gas at room temperature. III. When element is cooled from 70° to 10° , its particles get closely packed. A) I and II only B) I only C) I and III only D) III only Avanti – 9C01 – Matter in our Surrounding – Olympiad Practice Problems ss

12. Melting and boiling points of four substances are given in the table. 18 Melting point (° ) Boiling point (° ) 130 30 120 75 0 110 41 182 Which of the substances can be distilled using the given apparatus? A) and only B) and only C) only D) All of these. 13. How is brownian motion caused? A) Due to temperature fluctuations within the liquid phase. B) Due to attractions and repulsions between the charges on the colloidal particles. C) Due to impact of molecules of the dispersion medium on the colloidal particles. D) Due to pressure variations within the liquid phase. 14. Two different solutions and are poured into beakers of the same size in the figure. After two days, becomes lighter than . Which of the following conclusions are not true? i) Evaporation only takes place in . ii) Evaporation does not take place in . iii) The rate of evaporation of is higher than the rate of evaporation of . A) i) and ii) only B) i) and iii) only C) ii) and iii) only D) i), ii) and iii) 15. Which of the following water molecules , , or can easily escape to form water vapour? A) B) C) D) 16. A drop each of two non-corrosive and non-irritating liquids and at a temperature of 22° are placed on the skin. Liquid gives a more cooling sensation than liquid . Avanti – 9C01 – Matter in our Surrounding – Olympiad Practice Problems ss

Which of the following can be said about the liquids and ? 19 A) Liquid has higher boiling point than that of liquid . B) Liquid has higher latent heat of vaporisation than that of liquid . C) Liquid has lower latent heat of vaporisation than that of liquid . D) The boiling points of liquid and are equal. 17. A sample of a pure solid compound is heated until it melts completely. The compound is then allowed to cool until it solidifies again. The graph shows how the temperature of the compound changes with time. In which region of the graph both the liquid and the solid are present? A) A to B B) C to D C) B to C D) A to B and C to D 18. A gas can be best liquefied : A) By increasing the temperature B) By lowering the pressure C) By increasing the pressure and reducing the D) None of these temperature 19. Decrease in pressure causes _________ and increase in temperature causes _________. A) Decrease in intermolecular spaces, increase in kinetic energy of molecules B) Increase in intermolecular spaces, decrease in kinetic energy of molecules C) Decrease in intermolecular spaces, decrease in kinetic energy of molecules D) Increase in intermolecular spaces, increase in kinetic energy of molecules 20. The boiling point of a liquid is the temperature at which its vapor pressure is equal to the pressure of the gas above it. The normal boiling point of a liquid is the temperature at which its vapor pressure is equal to one atmosphere (760 torr). At higher altitudes: A) Boiling point of a liquid increases B) Boiling point of a liquid decreases C) No change in boiling point D) Melting point of solid increases 21. Latent heat of vaporisation is used to : A) Overcome the forces of attraction between molecules in solid state. B) Increase the kinetic energy of molecules in liquid state. C) Overcome the forces of attraction between molecules in liquid state. D) Increase the kinetic energy of molecules in vapour state. 22. In the case of the latent heat of fusion it is the heat required to change a substance from a solid to a liquid or vice versa while the latent heat of vaporization from a liquid to a gas or vice versa. Specific heat gives the amount of heat energy required for heating a substance of unit mass by 1° . Mercury is used as a thermometric liquid because it has: A) Lowest latent heat of fusion B) Lowest specific heat among all the liquids C) High specific heat among all the liquids D) Can’t say Avanti – 9C01 – Matter in our Surrounding – Olympiad Practice Problems ss