Required practicals 1

• Salt


  A compound containing a positive ion (metal ion) and a negative ion (from an acid)
• Sources of metal ions for salts

  • Metal
  • Metal oxide
  • Metal hydroxide
  • Metal carbonate
• Making a soluble salt using an acid


  1. Use dilute acid as limiting reactant

  2. Heat acid to almost boiling

  3. Add small amounts of metal oxide and stir

  4. Stop adding oxide when solution is blue

  5. Filter to remove unreacted oxide

  6. Evaporate solution to form crystals

  7. Allow crystals to form over 24 hours

  8. Dry the crystals
• Copper sulfate


  • Contains copper(II) ion as positive ion
  • Contains sulfate ion as negative ion
• Titration


  A procedure to determine the concentration of an unknown solution by reacting it with a solution of known concentration
• Normally, the titration is repeated several times until two readings within 0.1 cm³ are obtained, and the mean is taken as the final volume
• Investigating what happens when aqueous solutions undergo electrolysis

  1. Pour approximately 50 cm³ of copper(II) chloride solution into a beaker

  2. Place a plastic petri dish with two holes over the beaker

  3. Insert a carbon graphite rod into each hole (electrodes)

  4. Attach crocodile leads to the rods and connect to a low-voltage power supply

  5. Select 4 V on the power supply and switch it on
• Titration practical

  1. Use the pipette and pipette filler to add 25 cm3 of alkali to a clean conical flask.
  2. Add a few drops of indicator and put the conical flask on a white tile.
  3. Fill the burette with acid and note the starting volume.
  4. Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix.
  5. Stop adding the acid when the end-point is reached (when the indicator first permanently changes colour). Note the final volume reading.
  6. Repeat steps 1 to 5 until you get concordant titres .
• Electrolysis

  Wearing safety glasses, add sodium sulfate solution to a beaker, and connect two inert electrodes (make sure they do not touch) to a power supply.Completely fill two small test tubes with sodium sulfate solution and position a test tube over each electrode, then turn on the power supply and observe what happens at each electrode.Any gases produced can be collected in the test tubes and tested (squeaky pop test - hydrogen, relight a glowing splint - oxygen).