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Topic: Titration  (Read 2268 times)

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Offline HusamEddin

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Titration
« on: January 03, 2013, 08:34:10 AM »
Hi there :)
if we have a sample of .1 grams
this sample contains Mg(OH)2
the Mg(OH)2 in the sample has been titrated by 10ml of .08M HCl
calculate the percentage of Mg(OH)2 in the sample

I suggest the answer would be like the following:
number of moles of HCl is
.08X10/1000 = .0008 mole
one mole of Mg(OH)2 is titrated by 2 moles of HCl
So at the end point , Mg(OH)2 will has half the number of moles of HCl , ie>>.0004 mole
mass = #moles * molar mass
= .0004 * 58 = .0232 grams

percentage = .0232/.1 *100% = 23.2%


is it all right like that ? because some people told me that my answer is totally wrong !!!
help :(

Offline Hunter2

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Re: Titration
« Reply #1 on: January 04, 2013, 01:25:17 AM »
I would say its ok.

Offline ironnica

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Re: Titration
« Reply #2 on: January 04, 2013, 11:07:53 AM »
It all looks good. To get a more accurate answer, I would use gmm of 24.3g/mol instead of 24 but that would not put your answer off by much in comparison to what I assume you've been told.

Did you titrate the whole lot of the sample against HCl or just take some of the sample (i.e. taking some of a known volume of solution)?

Offline HusamEddin

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Re: Titration
« Reply #3 on: January 05, 2013, 11:49:20 AM »
didn't got your question  :-\

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