salts

• always soluble

  sodium, potassium, ammonium, nitrates
• most sulphates are soluble except for lead sulphate, silver sulphate and barium sulphate
• most chlorides are soluble except lead chloride and silver chloride
• most hydroxides are insoluble except from sodium hyrdoxide, potassium hydroxide and ammonium hydroxide
• most carbonates are insoluble except from potassium carbonate, sodium carbonate and ammonium carbonate
• acids release hydrogen ions, and are therefore the proton donors
• alkalis release hydroxide ions in water, making them the proton acceptors
• alkali + acid -> water
• acid + metal -> salt + hydrogen
• acid + metal oxide -> salt + water
• acid + metal hydroxide -> salt + water
• acid + metal carbonate -> salt + water + carbon dioxide
• hydrochloric acid makes a metal chloride
• nitric acid makes a metal nitrate
• sulphuric acid makes a metal sulphate
• phosphoric acid makes a metal phosphate
• excess is used for making soluble salts that are not SPA salts
• excess reaction:

  • Measure 50cm3 of acid into beaker
  • Plate beaker on hotplate and heat acid to around 50c
  • Add small spatulas of an insoluble oxide, hydroxide or carbonate into the warm acid and stir
  • Keep stirring until no more of the reactant disappears
  • Filter mixture into an evaporating dish
  • Heat filtrate until some of water is evaporated in order to make a saturated solution
  • Leave the saturated solution to cool and crystallise
• titration: used for making SPA salts, which are always soluble
• titration:

  • Fill burette with acid using a funnel
  • Record initial volume
  • Use a pipette and pipette filler to take out a 25cm3 sample of an alkali
  • Transfer sample to a conical flask
  • Add a few drops of indicator and place on a white tile to emphasise colour change
  • Run acid from burette into conical flask whilst swirling until colour change is noted
  • Record final burette reading
  • Repeat the experiment without any indicator by using previous measurements
• precipitation: used for making insoluble salts
• precipitation:

  • Mix together the solutions of 2 insoluble salts
  • Filter the mixture through filter paper using a funnel and a conical flask
  • Was the residue/precipitate left on the filter paper with distilled water
  • Pat the residue/precipitate dry or leave in a warm oven until completely dry
• copper sulphate crystals: excess
• making copper sulphate

  • Measure 50cm3 of sulphuric acid into a 150cm3 beaker
  • Place the beaker on a hotplate and heat acid to around 50c
  • Add small spatulas of copper oxide powder into the warm acid and stir
  • Keep adding copper oxide powder and stirring until no more disappears
  • Filter the mixture into an evaporating dish
  • Heat the filtrate until some of the water has evaporated in order to make a saturated solution
  • Leave the saturated solution to cool and crystallise
• lead sulphate: precipitation
• • Mix together lead nitrate solution with sodium sulphate solution in a beaker
  • Stir well
  • Use filter paper to filter the mixture into a conical flask using a funnel
  • Wash the residue with distilled water
  • Leave the residue to dry in a warm place
  • Pat dry
• Litmus:

  acidic - red

  alkaline - blue
• Phenolphthalein:

  Acidic - colourless

  Alkaline - pink
• Methyl orange:

  Acidic - red

  Alkaline - yellow
• Universal: 

  Acidic - red

  Alkaline - purple