Gases
In gases, the particles are much farther apart from one another as compared to solids and liquids [see Figure 22(c)]. The spaces (or distances) between the particles of a gas are very large. The force of attraction between the particles of a gas is negligible. So, the particles of a gas are free to move in any direction. The positions of particles of a gas as well as the spaces between the particles of a gas are not fixed. The particles of a gas have the maximum movement (or maximum kinetic energy). Due to this, the gases have the most disorderly arrangement of particles. Because of high kinetic energy and negligible forces of attraction, the particles of a gas move with high speeds in all directions. When the fast moving gas particles hit the walls of the container, they exert a pressure (called gas pressure). Thus, a gas exerts a pressure on the walls of its container. The pressure exerted by a gas is due to the collisions of the fast moving gas particles against the walls of the container. When a gas is put in an empty container, it quickly spreads throughout the container and fills it completely. If a gas is heated, the particles of gas start moving faster and faster.
We will now explain the properties of gases. A gas does not have a fixed shape because the positions of its particles are not fixed. A gas does not have a fixed volume because the spaces between its particles are not fixed. Since the particles of a gas are free to move anywhere, it takes the shape and volume of its container. A gas can be compressed easily because its particles are far apart and there are large spaces between them (which can be reduced by compression). A gas has a very low density because its particles are very far apart from one another. A gas fills its container completely because due to high kinetic energy and negligible forces of attraction, the particles of a gas are moving with high speeds in all directions. A gas flows easily because its particles are completely free to move anywhere.
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3. 2. Liquid to Gas Change : Boiling (or Vaporisation)
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4. 2. Latent Heat of Vaporisation (Liquid to Gas Change)
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5. Effect of 'Heating' and 'Cooling' on a Saturated Solution
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6. Classification Of Matter As Solids, Liquids And Gases
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9. Why Solids, Liquids and Gases Have Different Properties
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13. 2. The Particles of Matter have Spaces Between Them
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15. 1. Solid to Liquid Change : Melting
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16. 3. Gas to Liquid Change : Condensation
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20. 1. Latent Heat of Fusion (Solid to Liquid Change)
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24. 1. The Particles of Matter are Very, Very Small
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26. 4. The Particles of Matter Attract Each Other
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28. 3. The Particles of Matter are Constantly Moving
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29. Characteristics of Particles of Matter
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30. 4. Liquid to Solid Change : Freezing
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31. Two More States of Matter : Plasma and Bose-Einstein Condensate
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38. The Common Unit Of Temperature and Si Unit Of Temperatre
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39. To Show That Solids and Liquids Cannot be Compressed but Gases Can be Compressed Easily
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44. To Show that Liquids do not have a Fixed Shape but they have a Fixed Volume
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45. To Show the Presence of Water Vapour in Air
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49. Gases Can be Liquefied by Applying Pressure and Lowering Temperature
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50. To Show that Gases do not have a Fixed Shape or a Fixed Volume
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