Matter in our surrounding
- 2. MATTER Anything which occupies space and has mass is called matter. 2
- 3. CHARECTERISTICS OF MATTER The particle of matter are very very small. The particles of matter have space between them. The particles of matter are continuously moving. The particles of matter attract each other. 3
- 4. The particle of matter are very very small. TO SHOW THAT PARTICLES OF MATTER ARE SMALL Take 2-3 crystals of potassium permanganate and dissolve them in 100mL of water. Take out approximately 10mL of this solution and put it into 90mL of clear water. Take out 10mL of this solution and put it into another 90mL of water. Keep diluting the solution 5-8 times. Observance : this experiment shows that just a few crystals of permanganate can colour a large amount of water(say 1000mL). Conclusion : 4
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- 6. The particles of matter have space between them. TO SHOW THAT PARTICLES OF MATTER HAVE SPACE BETWEENTHEM We take about 100 mL of water in a beaker. And mark the level of water in the beaker with a marking pen. Now add 50gm of sugar to the beaker and dissolve it by stirring it with a glass rod. When all the sugar has dissolved, we get a sugar solution. Now look at the level, is it at the same level or it is displaced? OBSERVANCE : WE WILL FIND THAT EVEN AFTER DISSOLVING 50gm OF SUGAR, THE VOLUME HAS NOT INCREASED. CONCLUSION : THE PARTICLES OF MATTER HAVE SPACE BETWEEN THEM. 6
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- 8. The particles of matter are continuously moving. THE BEST EVIDENCE THAT PARTICLES OF MATTER ARE CONSTANTLY MOVING COMES FROM THE STUDIES OF DIFFUSION AND BROWNIAN MOTION. EXAMPLES:- a) when we light an incense stick (agarbatti) in one corner of a room, its fragrance spreads in the whole room quickly b) When a few crystals of copper sulphate are placed at the bottom of a beaker containg water, then water in the whole beaker turns blue slowly. 8
- 9. The particles of matter attract each other. There are some forces of attraction between the particles of matter which bind them together. 9
- 10. CLASSIFICATION OF MATTER Early Indian philosophers classified matter in the form of five basic elements- the ‘panch tatva’ – air, water, earth, fire and sky. Modern scientists have evolved two types of classification of matter based on its physical properties and chemical aspects. 10
- 12. SOLID In solids, the particles are closely packed. Solids have a fixed shape and a fixed volume. Solids cannot be compressed much. Solids have high densities. They are heavy. Solids do not flow. Solids have great force of attraction. 12
- 13. LIQUID In liquids, the particles are close together, but they are not as close as in solids. Liquids have a fixed volume but they have no definite shape. Liquids take the shape of vessel in which they are placed. Liquids cannot be compressed much. Liquids have moderate and high densities. They are usually less dense than solids. Liquids generally flow easily. 13
- 14. GAS Gases have neither a fixed shape nor a fixed volume. Gases can be compressed easily. Gases have very low densities. They are very, very light. A gas is much lighter than the same volume of solid or gas. Gases flow easily. In solids, the particles are much farther apart from one another as compared to solids and liquids. 14
- 15. BOSE-EINSTEIN CONDENSATE The BEC happens at super low temperatures. We have talked about temperature scales and Kelvin. At zero Kelvin (absolute zero) all molecular motion stops. Scientists have figured out a way to get a temperature only a few billionths of a degree above absolute zero. When temperatures get that low, you can create a BEC with a few special elements. Cornell and Weiman did it with rubidium (Rb). 15
- 16. PLASMA A plasma is a gas that has been energized to the point that some of the electrons break free from, but travel with, their nucleus. Gases can become plasmas in several ways, but all include pumping the gas with energy. A spark in a gas will create a plasma. 16
- 17. DIFFUSION The spreading out and mixing of a substance with another substance due to the motion of its particles is called diffusion. Diffusion is a property of matter which is based on the motion of its particles. Diffusion is fastest in gases and slowest in solids. The rate of diffusion increases on increasing the temperature of the diffusing substance. Diffusion is fastest in gases and slowest in liquid. 17
- 18. SI UNIT OF TEMPREATURE The common unit of measuring temperature (like melting points, boiling points, etc.). There is another scale of temperature called kelvin scale of temperature which is used by the scientist mainly for research work. The SI unit of measuring temperature is kelvin (K). 18
- 19. CHANGE OF STATE OF MATTER 19
- 20. EFFECT OF CHANGE OF TEMPERATURE By increasing the temperature, a solid can be converted into liquid state; and the liquid can be converted into gaseous state. By decreasing the temperature, a gas can be converted into liquid state; and a liquid can be converted into solid state. 20
- 21. SOLID TO LIQUID: MELTING The process in which a solid substance changes into a liquid on heating, is called melting (or fusion). The temperature at which a solid substance melts and changes into a liquid at atmospheric pressure is called melting point. The melting point of a solid is a measure of the force of attraction between its particles (atoms or molecules). When a solid is heated sufficiently, it changes its physical state and becomes a liquid. 21
- 22. LIQUID TO GAS: VAPORISATION The process in which a liquid substance changes into a gas rapidly on heating is called boiling. The temperature at which a liquid boils and changes rapidly into a gas at atmospheric pressure, is called boiling point of the liquid. The boiling point of liquid is a measure of the force of attraction between it’s particles. When a liquid is heated, it changes its physical state and becomes a gas. 22
- 23. GAS TO LIQUID: CONDENSATION The process of changing a gas( or vapor) to a liquid by cooling, is called condensation. Please note that condensation is reverse of boiling. 23
- 24. LIQUID TO SOLID: FREEZING The process of changing a liquid into a solid by cooling, is called freezing. Freezing means solidification. Please note that solidification is reverse of melting. The state of matter can be changed by changing the temperature (by heating or cooling). 24
- 25. LATENT HEAT The heat energy which has to be supplied to change the state of a substance is called its latent heat. Latent heat does not raise the temperature. But latent heat has always to be supplied to change the state of a substance. Why temperature does not rise? The latent heat which we supply is used up in overcoming the forces of attraction between the particles of a substance during the change of state. Latent heat is of two types- i) Latent heat of fusion. ii) Latent heat of vaporization. 25
- 26. LATENT HEAT OF FUSION The heat energy which is required to change the state of matter from solid to liquid is called latent heat of fusion. 26
- 27. LATENT HEAT OF VAPORISATION The heat energy required to change the state of matter from liquid to gas is known as latent heat of vaporization 27
- 28. SUBLIMATION The changing of a solid directly into gas on heating, and of vapors into solid on cooling, is known as sublimation 28
- 29. EFFECT OF CHANGE OF PRESSURE The physical state of matter can also be changed by changing the pressure. Gases can be liquefied by applying pressure and lowering temperature. 29
- 30. EVAPORATION The process of a liquid changing into vapor( or gas) is called evaporation. FACTORS AFFECTING EVAPORATION Temperature: the rate of evaporation increases on the increasing of temperature. Surface area: the rate of evaporation increases on the increasing of surface area. Humidity: when the humidity of air is low, then the rate of evaporation is high. Wind speed: the rate of evaporation increases on the increasing of wind speed. 30
- 31. COOLING CAUSED BY EVAPORATION The cooling caused by evaporation is based on the fact that when a liquid evaporates, it draws (or takes) the latent heat of vaporization from ‘anything’ which it touches. By losing heat, anything gets cooled. 31
- 32. PRESENCE OF WATER VAPOUR IN AIR Presence of water vapour can be shown by following: We take a steel tumbler and put some well crushed ice into it. Wipe the tumbler with a cotton cloth to make the surface clear and dry. Allow the ice tumbler undisturbed for 5 minutes. Observance: a large number of tiny droplets of water appear on the outer surface of the tumbler. Reason : the air around the steel tumbler contains water vapour in it. When these water vapor come in contact with cold, outside surface of tumbler, they condense to form tiny drops of liquid water. 32
- 33. KEY POINTS 1. Matter- Matter is anything which occupies space and has mass is called matter. Air and water, sugar and sand, hydrogen and oxygen etc. Matter is made up of very small tiny particles. Particles of matter have space between them they attract each other. 2. Classification- On the basis of physical properties, matter is classified as solids, liquids and gases. On the basis of chemical properties, matter is classified as elements, compounds and mixtures. • Solids- Solids have strong molecular force and a definite shape and size solids can neither flow nor be compressed. • Liquids- Liquids have weak intermolecular flow and large intermolecular spaces. Liquids do not have a definite shape but can flow. • Gases- Gases have weak intermolecular flow, high compressibility, and no definite shape and volume. 3. Physical properties of matter- Matter is made up of particles which are very small in size. Everything around us is made up of tiny pieces or particles. The particles of matter are constantly moving (they are in motion).The particles which make up matter are atoms and molecules. 4. Interchange in states of matter- Matter can change its state in solid, liquid or gas depending upon the type of matter. 5. Diffusion- The mixing of a substance with another substance due to the motion or movement of its particles is called diffusion. It is one of the properties of materials. The diffusion of one substance into another substance goes on until a uniform mixture is formed. Diffusion takes place in gases, liquids and solids. 33
- 34. 6. Latent heat- Latent heat is the heat energy which has to be supplied to change the state of a substance. Latent heat does not increase the temperature of a substance. But latent heat has to be supplied in order to change the state of a substance. Latent heat can be of fusion or of vaporization. 7. Sublimation- The changing of a solid directly into vapours on heating and of vapours into solid on cooling, is known as sublimation. When these solid substances are heated, their particles move quickly and they separate completely to form vapor (or gas). Similarly when these vapor (or gas) is cooled, these particles slow down so quickly that they become fixed and form a solid. 8. Evaporation- The process of conversion of a liquid into vapour (or gas) at its boiling point is called evaporation. Some particles in liquid always have more kinetic energy than the others. So, even when a liquid is well below its boiling point, some of its particles have enough energy to break the forces of attraction between the particles and escape from the surface of the liquid in the form of vapour. Thus the fast moving particles of a liquid are constantly escaping from the liquid to form vapor or gas. Temperature, surface area of liquid, humidity, and wind speed are fators that affect evaporation. Evaporation causes cooling effect. 9. Effect of Change of Pressure: The physical state of matter can also be changed by increasing or decreasing the pressure to it. Gases can be liquefied by applying pressure and lowering temperature. When high pressure is applied to a gas, it gets compressed, and when in addition to it we lower its temperature, it gets converted into liquid. So, we can also say that gases can be turned into liquids by compression and cooling. 34
- 36. WHAT ARE CHARECTERISTICS OF MATTER? Below are the characteristics of matter The particle of matter are very small. The particles of matter have space between them. The particles of matter are continuously moving. The particles of matter attract each other. 36
- 37. What do you mean by following terms- (a) evaporation (b) sublimation (c) condensation Answer: a) The process in which a liquid substance changes into a gas rapidly on heating is called evaporation. b) The changing of a solid directly into gas on heating, and of vapors into solid on cooling, is known as sublimation. c) The process of a liquid changing into vapor( or gas) is called evaporation. 37
- 38. Define latent heat of fusion and latent of vaporization. The heat energy which is required to change the state of matter from solid to liquid is called latent heat of fusion. The heat energy required to change the state of matter from liquid to gas is known as latent heat of vaporization 38
- 39. THANK YOU 39