States of matter

• properties of solids:

  • strong forces of attraction between particles
  • particles are closely packed in a fixed position
  • definite shape and volume
  • particles vibrate in a fixed position
  • If you heat up the solid the particles gain energy and vibrate more which weakens the force between them
• properties of a liquid:

  • weak forces of attraction between particles
  • particles are free to move
  • particles stick together and are compact
  • they have a definite volume
  • shape can flow to fit a container
  • If you heat it up the particles gain energy and move around faster
• properties of a gas:

  • very weak forces of attraction
  • particles are free to move
  • Don't have definite shape or volume
  • always fill the container - spread out
  • constantly moving with random motion
  • when the particles are heated up the gas will expand and the pressure will increase
• when a gas turns into a liquid its called condensing
• when a liquid turns into a solid its called freezing
• when a solid turns into a liquid its called melting
• when a liquid turns into a gas its called evaporation
• pure substance - contains only one type of compound/element
• pure substances have melting and boiling points at a specific temperature
• Impure substances - A mixture of two or more substances that are not chemically bonded together
• Impure substances have a range of melting and boiling point temperatures
• Formulations - mixture that has been prepared using a specific formula
• formulations have a precise amount of different components and have a particular function
• this is simple distillation

  
• This is fractional distillation

  
• simple distillation is used when you need to separate a liquid from a solution
• Fractional distillation is used when you need to separate mixtures of liquids
• mixture - solid in a liquid that doesn't dissolve
• Solution - solid in a liquid that does dissolve
• filtration - separate insoluble solids from liquids
• Filter paper has small holes which allows water to pass through but not solids.

  
• This is evaporation

  
• paper chromotography is used to separate different dyes in an ink.
• chromotogram - pattern of spots left on the chromatography paper
• mobile phase - a liquid or gas that carries the solvent through the stationary phase
• stationary phase - a solid or liquid material that remains fixed in place while the mobile phase passes through it.
• Rf value = distance travelled by substance divided by distance travelled by solvent
• The three types of waste are: domestic, agricultural and industrial
• For domestic and agricultural waste we have to remove any organic matter or harmful microbes which could pollute fresh water.
• For industrial waste we have to remove any harmful chemicals
• sewage treatment consists of 3 main steps:

  1. screening
  2. sedimentation
  3. biological breakdown
• sewage sludge and effluent are produced as byproducts of treating waste water
• sewage effluent is produced under aerobic conditions
• sewage sludge is produced under anaerobic conditions, which produces methane which can be used as a fertiliser
• potable water - water that is safe to drink
• criteria for potable water:

  • levels of dissolved substances need to be fairly low
  • ph between 6.5-8.5
  • no micro-organisms