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Topic: Iodine Solution  (Read 3989 times)

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Offline defencegrid

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Iodine Solution
« on: January 16, 2017, 01:32:35 AM »
I have a prac that says prepare 20ml of a 0.005M Iodine solution in Potassium Iodine. 
In brackets it tells you how to make a 1M solution of Iodine solution in Potassium Iodine.

it says:

"20ml 0.005M iodine solution (Dissolve 2.0g KI in 40ml water, add 1.25g of l2 and make up to 1L"

What I don't get, is that the molar mass of I2 is 126.90447 .  so 1.25/126.90447 = 0.0098M

So that molarity of that solution is about 0.0098, when we need a 0.005M solution?






Offline mjc123

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Re: Iodine Solution
« Reply #1 on: January 16, 2017, 04:52:31 AM »
126.9 is the molar mass of I, not I2.

Offline defencegrid

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Re: Iodine Solution
« Reply #2 on: January 16, 2017, 08:25:22 PM »
126.9 is the molar mass of I, not I2.

Oh yeah....Great, thank you.

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