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# iodine clock watch

1. hi i kinda need help from other members because for my iodine clock experiment, i am going to start my experiment can anybody tell me which variables are changes and how do you work out concentration from your results, cheers
2. (Original post by writemaster)
hi i kinda need help from other members because for my iodine clock experiment, i am going to start my experiment can anybody tell me which variables are changes and how do you work out concentration from your results, cheers
i thought you said you lost your results in your other post, so which is true?
3. yep i did loose my results thats why am going to do my experiment again i cannot remember wchich variables i have changed lol orry if it confused lol. can you help me?
4. (Original post by writemaster)
yep i did loose my results thats why am going to do my experiment again i cannot remember wchich variables i have changed lol orry if it confused lol. can you help me?
Ermm, iodine clock is famous in most a level investigation. Key thing here is to find the order of the reactants in the rate equation.
You mix acid, hydrogen peroxide and iodide. The reaction rate is monitored by quenching the solution with thiosulphate and time recorded for the clear solution to go dark blue is recorded.

After some time the solution always changes color to a very dark blue, almost black.

Variables,
To find let say the order with respect to H+, change only concentration of H+ in each experiment(say do at 4 different H+ concentration), but maintain the same concentration of the other reactants

Then do the same for the other reactants, changing only one variable at a time.

Then you can get the orders and form the rate eqn.

You can also calculate the activation energy of the reaction; change only the temperature at which reaction takes place, but keep the concentrations of all reactants used constant. Then look up how to use the Arrhenius eqn to calculate this.

p/s - please don't use "text" language here
5. thank you for yo ur reply

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