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November 01, 2025, 01:09:20 pm
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Author Topic: vea's chem question!  (Read 1005 times)  Share 

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vea

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vea's chem question!
« on: March 29, 2011, 09:15:43 pm »
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Hi guys, this thread will contain all my nooby questions for chem. :)

To start off:

In a gravimetric analysis of sulfate in fertiliser, we are precipitating sulfate as barium sulfate.

Before we actually precipitate the sulfate, we added 3ml of 2M HCl. Now I know that the H+ ions are used to make the precipitation specific, preventing OH- from precipitating with Ba2+ and also preventing CO3 2- from precipitating, but what is the purpose of the Cl- ions? I have written down that it is to make sure there are a lot of contaminating Cl- ions but I'm not too sure why you would want this?

Thanks in advanced.
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wildareal

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Re: vea's chem question!
« Reply #1 on: April 28, 2011, 12:04:00 am »
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It is just a spectator ion to keep the Barium ion stable so that it can swap and form Barium Sulphate.
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Wildareal '11

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vea

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Re: vea's chem question!
« Reply #2 on: April 28, 2011, 12:27:34 am »
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Haha I had it cleared up but thanks for the reply!
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