Tuesday, 8 May 2012

Change of state

I don't understand why this is highlighted bold in the specification, showing that it's for Single Science, because this is so simple. 

5.7 understand that a substance can change state from solid to liquid by the process  of melting

5.8 understand that a substance can change state from liquid to gas by the process of evaporation or boiling

5.9 recall that particles in a liquid have a random motion within a close-packed irregular structure

5.10 recall that particles in a solid vibrate about fixed positions within a close-packed regular structure

State of matter
Arrangement of particles
Movement of particles

  • Closely packed together, usually in a regular pattern, occupying minimum space.

  • This results in solids having high densities.

  • Vibrate about fixed positions only. Held in position by very strong intermolecular bonds.
  • This explains why solids have fixed volumes and shapes.

  • Randomly arranged with the particles slightly further apart as compared to that of solids.
  • This results in liquids having  relatively high densities.

  • Free to move about but confined within the vessel containing it. Have attractive forces between particles.
  • This explains why liquids have fixed volume but will take the shape of vessels containing them.

  • Very far apart. Particles are randomly arranged and will occupy any available space.
  • This results in gases having very low densities.

  • Particles have very little attraction between them and move about randomly at very high speed.
  • This explains why gases have no fixed volume and shape, and why they are highly compressible.

1 comment:

  1. theze images cannot be viewed and i am only dissappointed about it! would be helpful with pix... :)
    anyway this is very much helpful than our own teachers.! well thank u! :D


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