SQA
HIGHER
CHEMISTRY


The Effect of Concentration on Reaction Rate

UNIT 1
PPA1

The aim of this experiment is to find the effect of varying the concentration of iodide ions on the rate of reaction between hydrogen peroxide and an acidified solution of potassium iodide.

The course of the reaction can be followed by carrying it out in the presence of small quantities of starch and sodium thiosulphate ions. As the iodine molecules are produced, they immediately react with the thiosulphate ions and are converted back to iodide ions:

This simulated practical is not like a normal simulation, where you press the button and the work is done for you, in this simulation you must take the readings and plot the graphs yourself.

Two versions of the practical have been produced, click on the option that best suits your needs:

  1. A partially completed experiment In this experiment the solutions have been made up and for you, all you have to do is run the experiment and plot the results and draw your conclusions.
  2. A complete experiment In this experiment you must define the volumes of chemicals to used for each run before performing the experiment.
NOTE: To progress through the experiment, click on the "tabs" at the top of the program to change to different screens

Complete the tasks on each screen and then move on to the next tab to the right.

You can browse the different screens if you want at any time, in fact it's probably a good idea to have a look at them all before you start. As you might expect, some things later in the experiment won't work unless you've actually run the experiment.

If you get stuck, use the button at the top right of each screen.