Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: missaturn on February 22, 2008, 03:02:57 AM
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I need some guidance for the calculation of concentration of chemicals which I plan to dilute as stock solution. i have three chemicals which provide different information, . How to calculate the concentration of the chemicals so i can prepare a stock solution from them? Below are the information provided:
a)nitrosomorpholine: 1ml, FW 116.12
b)n-nitrosodiethylamine: 10ml, d=0.950, MW: 102.14
c)nitrosopyrrolidine: 99%, FW=100.12, d=1.094
Thanks.
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Dear Missaturn;
You don’t believe you have forgotten some information about your Problem?
Or should it mean that all is mixed together, but in this case what’s the volume/mass of Nitrosopyrrolidine?
I think in this form nobody can solve anything, as nobody (except you) can spend all the missing information.
Please check your Problem once again.
Good Luck!
ARGOS++
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Argos is correct, how can anybody tell you how to prepare a stock solution when you have not provided the necessary infomation on the concentrations or relative ratios of the individual components which are required.
I'm up for the challenge of helping out, but I'm not telepathic (just expected to be ::))
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A stock solution is a concentrated solution that you prepare for later dilution. There are a number of reasons for this. A substance may not be very soluble in water, you'd need say a 0.01 M solution, but you'd never be sure that tiny amount dissolved. You'd prepare a 0.1 M solution in alcohol or other solvent, then dilute in water.
Even if a substance is somewhat soluble, you wouldn't be sure a small amount was well mixed in a large volume. So you'd prepare a somewhat more concentrated stock solution, then dilute for working solution.
Like everyone else said, your protocol should tell you what the stock solution concentration should be, unless they've told you elsewhere, or expect you to ask some local expert, check the flasks in the lab for what's written on them, check published literature, etc.
We can't just suggest 0.1 M or 1 M for a stock solution, because don't know how soluble your solids are, how stable they are in concentrated or dilute solution, or what your application is.