Practicals

• 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
• 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 solution on chromatography paper

  2. Hang paper in beaker of water, water moves up by capillary action (mobile phase)

  3. Lighter particles move further up paper than heavier ones (separation)

  4. Calculate Rf value (distance solute moved / distance mobile phase moved)
• Water purification


  1. Heat water in flask, collect condensed water (distillation)

  2. Removes salts and microbes, produces potable water
• Identifying ions


  1. Flame test for metal ions

  2. Add acid and barium chloride to test for carbonate, halide, and sulfate ions
• If you've purified water well, you shouldn't see positive tests for sodium or chloride ions