states of matter

• describe the arrangement of particles in solids

  • tightly packed together in a regular arrangement
• describe the movement of particles in solids

  vibrate in fixed positions
• describe the arrangement of particles in liquids

  • close together but able to move past each other
• describe the movement of particles in liquids

  • vibrate and move around each other
• describe the arrangement of particles in gases

  well separated with no regular arrangement
• describe the movement of particles in gases

  • vibrate and move freely at high speeds
• compare the relative energies of particles in solids, liquids and gases

  • particles in a solid = least amount of energy
  • particles in a gas = most energy
• what does 'interconversion of state' mean?

  • when matter changes from one state to another
  • due to changes in temperature/ pressure
• what is the name for the state change from solid to liquid?

  melting
• what is the name for the state change from liquid to solid?

  freezing
• what is the name for the state change from liquid to gas?

  evaporation
• what is the name for the state change from gas to liquid?

  condensation
• describe the forces between particles in solids

  • strong forces of attraction between particles which keeps them in fixed positions
• describe the forces between particles in liquids

  • weaker attractive forces than solids
• describe the forces between particles in gases

  • weakest intermolecular forces
  • so particles are in random movement
• how does a physical change differ from a chemical change?

  • physical change: changes in forces between particles- particles themselves remain the same + chemical properties remain the same
  • a chemical change: affects the chemical properties of the substance
• True or false? 'Physical changes are relatively easy to reverse'

  • true
  • relatively easy to reverse: no new product is formed during changes of state
• what is the term for when a solid changes straight into a gas?

  sublimation
• describe what happens with the particles when a solid is heated and melts into a liquid

  • heated: particles absorb thermal energy-> converted into kinetic energy
  • particles in the solid vibrate more
  • causes solid expand until structure breaks + becomes a liquid
• describe what happens with the particles when a liquid is heated and evaporates into a gas

  • heated: particles in a liquid expand
  • some particles on the surface gain sufficient energy to overcome intermolecular forces + evaporate
  • at boiling point: all of liquid particles gain enough energy to evaporate
• substance A melts at -183 degrees and boils at -50 degrees. What state is A at -90 degrees?

  liquid
• what is the interconversion of state from a solid to a gas?

  sublimation