Required Practicals

• Independent variable


  • The thing you change
• Dependent variable


  • The other thing that changes as a result which you measure
• Control variables


  • Things that could change but we keep them the same throughout in order to ensure the results are accurate
• Always say what piece of equipment you use for each measurement, don't just say measure the length of the object
• State the flipping obvious, if you think surely they don't want me to put that, put it down anyway as you never know what marks you might pick up
• Talk about the accuracy of measurements, how will you reduce errors and uncertainties
• Do multiple or repeat measurements or readings to calculate a mean
• Write answers in bullet point format, it helps you and the examiner keep track of how many points are being made
• Making salt crystals


  1. Heat concentrated sulfuric acid in a beaker

  2. Add excess copper oxide

  3. Filter out unreacted copper oxide

  4. Gently heat the solution in an evaporating basin over a water bath to get solid copper sulfate crystals
• Electrolysis


  1. Put solution in a beaker

  2. Use two carbon electrodes, connect to power supply

  3. Positive electrode (anode) is oxidised, negative electrode (cathode) is reduced

  4. Depends on reactivity of ions in solution
• Temperature changes


  1. Carry out reaction in insulated poly-ion cup with thermometer

  2. Add reactants, record maximum temperature reached

  3. Repeat with increasing volumes of alkali

  4. Plot graph to find amount of alkali needed to neutralise acid
• Rates of reaction


  1. Measure volume of gas produced over time

  2. Or measure time for reaction mixture to become cloudy

  3. Change independent variable like temperature or concentration
• Chromatography


  1. Spot sample on chromatography paper

  2. Hang paper in solvent, let it move up by capillary action

  3. Calculate Rf values to identify components
• Water purification


  1. Distil water to leave pure water

  2. Use knowledge of flame and precipitate tests to identify ions
• Neutralisation titration


  1. Measure volume of alkali with pipette

  2. Add acid from burette slowly until indicator changes colour

  3. Use moles to calculate unknown concentration
• Flame test


  • To identify metal ions
• Precipitate tests


  • To identify non-metal ions like carbonate, halides, sulfate