Simulation rate of reaction – iodine clock

Simulation rate of reaction – iodine clock
The iodine clock reaction is a so called non-continuous method of detecting change during a reaction. In this activity you are going to investigate the effect of concentration and temperature on the rate of reaction of the “iodine clock” reaction.
The reaction you are going to investigate is
2I^-(aq) + S₂O₈^2-(aq)  I₂(aq) + 2SO₄^2-(aq) Reaction 1

I₂(aq) + 2S₂O₃^2-(aq)  2I^-(aq) + S₄O₆^2-(aq) Reaction 2

I₂(aq) + (C₆H₁₀O₅)_n  H₂O  blue complex Reaction 3
In summary, iodide (I^-) and persulfate ions (S₂O₈^2-) react to produce iodine (I₂) and sulphate ions (SO₄^2-) in reaction (1). This iodine is immediately consumed by the thiosulfate ions (S₂O₃^2-) in a pathway described by reaction (2). As soon as all of the S₂O₃^2-ions are consumed, the excess iodine produced in (1) is free to react with starch, turning the solution blue (3). The amount of thiosulfate ions added tells how much iodine had been produced in the time taken for the reaction to turn blue.
Perform the simulation

http://introchem.chem.okstate.edu/DCICLA/iodine_clock.html

1. 
   Use the setting in the simulation for concentrations of I^- and S₂O₈^2-, 25°C. Perform the simulation 5 times or until the time taken for the reaction to occur don´t vary more than 0.01s.
   
2. 
   Change the concentration of I^- and determine the time taken for the reaction to occur as above.
   
3. 
   Change the concentration of S₂O₈^2- and determine the time taken for the reaction to occur as above.
   
4. 
   Use the original setting and investigate how temperature affects rate of reaction.
   

Result: Write down the results in a table. Draw a graph using the data from the temperature simulations. Calculate the rate of reaction.

The report will be assessed on An, Ev and Comm.