Required practicals

• Colour change

  1. change temperature
  2. change concentration
• Required Practical – Colour change - Change temperature

  • Measure 30 cm3 of sodium thiosulfate solution pour into a conical flask.
  • Measure 10 cm3 of hydrochloric acid.
  • Place flask on top of a cross, add the acid, swirl and begin the stop watch.
  • Measure the time taken for the cross to disappear.
  • Repeat the experiment at the same temperature 2 more times.
  • Repeat the experiment at different temperatures.
• Required Practical – Colour change - Change temperature

  Variables

  Independent – Temperature of the hydrochloric acid.

  Dependent – time taken for the cross to disappear

  Controls – Concentration of solutions, starting temperature of sodium thiosulfate, volumes of solutions.
• Required Practical – Colour change- Changing concentration

  • Measure 30 cm3 of sodium thiosulfate solution pour into a conical flask.
  • Measure 10 cm3 of hydrochloric acid.
  • Place flask on top of a cross, add the acid, swirl and begin the stop watch.
  • Measure the time taken for the cross to disappear.
  • Repeat the experiment with the same concentration of hydrochloric acid 2 more times.
  • Repeat the experiment with different concentrations of hydrochloric acid.
• Required Practical – Colour change- Changing concentration

  Variables

  Independent – concentration of the hydrochloric acid.

  Dependent – time taken for the cross to disappear

  Controls – Concentration of sodium thiosulfate, starting temperature of solutions, volumes of solutions.