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Questions 2.12

  1. Name the three (3) physical states of matter. --------------------------
  2. Explain why liquids and gases have no definite shape, but take the shape of the container.---------------
  3. Liquids have definite volume but gases do not. Explain. -------
  4. State the properties that are common to all the three states of matter?--
  5. Explain why
  6. solids have definite shape and volume-------------------
  7. liquids have definite volume but indefinite shape---------------------------
  8. gases have no definite volume.----------------


Answers to Questions 2.12

  1. Solid, liquid, and gas
  2. Particles (molecules) of liquids and gases move freely and randomly; so they spread till they reach the wall of the container. Accordingly, they take the shape of the container.
  3. The upward spread of molecules in liquids is prevented by surface tension. Gases do not have a surface; so their molecules spread freely upwards for as long as there is space. Their volume is therefore the volume of the container.
  4. Tiny invisible particles. Continuous movement of particles. Mass.
    1. Particles in solids vibrate at fixed positions; so they have no tendency to spread out and change shape or volume.
    2. Upward movement of molecules of a liquid is prevented by surface tension; so volume does not change. But they can spread horizontally upto the wall of the container; so they take the shape of the container.
    3. Molecules of a gas move freely and randomly in all directions, but with no surface tension; so they spread out in all directions, provided there is space.