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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Alexis7 on February 25, 2013, 10:35:08 PM

Title: Iodide Persulfate Kinetics Experiment Question
Post by: Alexis7 on February 25, 2013, 10:35:08 PM

Hello,

Maybe you guys have done this experiment before...

But anyways I'll lay out what's given...

The reaction is:

2 I(aq)  +    S208(aq)  -----------> I2(aq)          +           SO4(aq)

The rate= k  [ I   ]^a[S208]^b

[KI] = 0.1M                             [NaCl]= 0.10M             
[Na2S2O3]= 0.005M                 [Na2SO4] = 0.10M 
[K2S208]= 0.10M                     [CuSO4]= 0.01M

For the first experiment. Contents of test tube A were poured into test tube B, and it created a blue-violet complex, it took 133 seconds for a colour change.

Test tube A: 10.0ml of KI(aq) and 5.0 ml NaS2O3(aq)
Test Tube: 10.0 ml of K2S208 and 1.0 ml starch (aq)               

Anyways I need to calculate the concentration of [ I ] , [S208], along with the rate constant and and initial rate.

I know how to calculate the initial rate and rate constant easily, but to do that I need to find the concentration but for some reason I just can't figure out how to calculate the concentration of [ I ] and [S2O8].

It seems to be the easiest part, but I simply have to clue where to start. Will M1V1=M2V2 work?

Does anyone have any tips or advice where I can start to find Concentration. Everything else is easy I just have difficulties solving for it for some reason.

Thanks anyways

~Alexis

Title: Re: Iodide Persulfate Kinetics Experiment Question
Post by: Borek on February 26, 2013, 04:28:00 AM

Quote from: Alexis7 on February 25, 2013, 10:35:08 PM

Will M1V1=M2V2 work?

That's the way. It is just a matter of correctly calculating V₁ and V₂ (not that it is difficult).