Chemical analysis

• describe the method and resulets for the carbonate test- anion test

  add dilute acid if it fizzes it is positive

  should produce co2 turns limewater cloudy
• describe the method and results for the sulphate test- anion test

  add a few drops of HCl to barium chloride if white precipitate appears it is positive
• describe the method and reslts for the halide test- anion test

  add nitric acid + silver nitrate solution it is positive if results in a precipitate

  iodide- yellow precipitate

  bromide- cream precipitate

  chloride - white precipitate
• what is a precipitate

  an insoluable solid in a mixture formed in a reaction (group 1 ions dont form a precipitate)
• write a method to test for cations

  add sodium hydroxide to your solution

  observe and record any change

  add exess sodium hydroxide and record any change
• colour precipitate for...


  copper II - blue

  iron II - green/grey

  iron III - brown

  aliminium - white

  calcium - white

  magnesium - white
• write a method to test for cations - flame tests

  clean a platinum loop by dipping it in HCl and place it in the blue flame until it burns without any colour

  dip the loop into the sample and put it back into the roaring flame

  observe and record the colour of the fame
• what is the colour of the flame for...

  lithium - crimson

  sodium - yellow

  potasium - lilac

  copper - green

  calcium - orange/red
• write a method to identify oxygen

  oxygen - relights a glowing splint
• write a method to identify hydrogen

  hydrogen - a squeaky pop
• write a method to identify CO2

  CO2 - the limewater turns milky
• write a method to identify chlorine

  chlorine - bleached litmus paper
• why do we use a pencil line on the origin line


  pencil is insoluble so wont dissolve
• why would you put a lid on the beaker


  prevents evaporation of the solvent
• what is important about the solvent level

  the solvent must be at a lower level than the origin line so the substance doesnt dissolve in the solvent
• what is the stationary phase


  chromatography paper
• what is the mobile phase


  solvent
• how do we work out the Rf value

  Rf = distance moved by substance / distance moved by solvent