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Topic: calculating equilibrium constants from titration  (Read 11388 times)

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Offline allisonsb02

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calculating equilibrium constants from titration
« on: October 17, 2006, 05:41:00 PM »
I just performed an experiment on chemical equilibrium of iodine in cyclohexane where I2 + I gives I3. A cyclohexane with iodine layer and an aqueous layer were formed so that the concentrations of I2 in the two phases could be compared. We titrated with thiosulfate to the endpoint after adding starch and KI. We obtain thiosulfate volumes and have initial concentrations of KI and I2. I am not sure how to calculate the concentration of I2 for each layer. Then from there I need to calculate the distribution constant and the equilibrium constant. I'm not sure how to make any of these calculations. Can anyone help?

Offline Borek

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Re: calculating equilibrium constants from titration
« Reply #1 on: October 17, 2006, 06:08:21 PM »
What have you titrated, as it is not clear from your post.
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Offline allisonsb02

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Re: calculating equilibrium constants from titration
« Reply #2 on: October 17, 2006, 08:44:53 PM »
Sorry I was freaking out since I didn't know what I was doing. It ended up being fairly easy. It just involved simple stoichiometric calculations. I got it figured out!!!

Offline Borek

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Re: calculating equilibrium constants from titration
« Reply #3 on: October 18, 2006, 02:45:15 AM »
At least outline the procedure for others.
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Offline allisonsb02

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Re: calculating equilibrium constants from titration
« Reply #4 on: October 19, 2006, 08:16:01 PM »
I titrated with 0.1M thiosulfate into an aqueous layer of iodine in cyclohexane using starch as an indicator. The amount of aqueous layer used was 50 mL. To calculate the concentration of I2:

=(volume titrated)(0.1M)(1 mol I3/ 2 mol S203)(1 mol I2/ 1 mol I3)(1 / 0.05L)

which gives the molarity of I2 in the aqueous layer. This experiment was titled "Chemical Equilibrium in Solution" and this was just one part of the calculations.

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