chemistry topic 2

• Solids

  • Fixed shape
  • Fixed volume
• Liquid

  • Takes containers shape
  • Fixed volume
• Gas

  • Takes on containers shape
  • Takes on containers volume
• Lattic means fixed shape
• Which particle arrangements have the most energy

  Gas
• Solid to gas

  Sublimination
• Gas to solid

  Deposition
• Gas to liquid to solid

  Condensing and freezing
• Pure substance is only made up of one element or compound
• Mixture is lost of substances mixed up toghether but not BONDED
• What do impure/mixtures melt over

  Range of tempatures (shown by slanted line on grap)
• What do pure substance have

  Specific melting and boiling point (shown by flat line on graph)
• Filtration is used to separate insoluble solid from liquid

  
• Crystallization is used to separate soluble solid from solution(soluble solids dissolve in liquid to form solution)
• Crystallization steps

  1. Solution is heated by bunsen berner
  2. Liquid in solution evaporates
  3. Solution is more concentrated
  4. Solid crystals form on edge of dish
  5. When liquid evaporates dry crystals left behind
• In simple distillation the liquids have to have different boiling points to be seperated
• Distillation apparatus consists of flask, condenser, thermometer, delivery tube and water bath
• Simple distillation steps(seperatingpurenwater from salty seawater )

  1. Heat solution in flask attached to condensor
  2. As solution heats the part of liquid with lowest boiling point evaporates first(water evaporates)
  3. Water then travels as vapor through condenser and turns into pure liquid

  
• Potable water is water that is safe to drink and is free from harmful bacteria and other microorganisms
• Fractional distillation is when we want to separate two or more substances which all have similar boiling points but are not miscible (do not mix together).
• How to make waste and ground water potable

  1. Sedimentation(large insolubleproducts will sink to bottom of )
  2. Filtration(filter all small particles out)
  3. Chlorination(remove any pathogens or microorganisms)
• Simple distillation is used to seperate solvent from solution
• Making sea water portable using distillation

  1. Filter seawater
  2. Boil it
  3. Water vapour is cooled and condensed
• Water used in analysis must be pure because any dissolved salts could react with substance you are analysing leaving you with fake result
• Changes of state are physical changes . Why aren't they chemical changes??


  No new substances are formed during changes of state
• If given tempature is below melting point it's a


  Solid
• If given tempature is above boiling point


  Gas
• If given tempature is between melting and boiling point it's a 


  Liquid
• During melting evaporating and boiling the particles gain energy, which is used to break or overcome:

  some of the bonds between particles during melting

  • all the remaining bonds between particles during evaporating or

  boiling
• For freezing and condensation to happen what needs to be transferred 


  Energy
• Why do particles lose energy during freezing and condensation 


  As the bonds form between the particles.