Of Acids, Titrations and fickle normality.

Composition and transformation of substance.

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Re: Of Acids, Titrations and fickle normality.

#21  Postby natselrox » Apr 22, 2010 10:26 am

0.04 and 36%...makes sense.
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Re: Of Acids, Titrations and fickle normality.

#22  Postby Oeditor » Apr 30, 2010 10:58 pm

A bit late to ask now, but I'm puzzled. I had to make some dil HCl from conc and being about 13 years away from a lab had to settle for gravimetry using the kitchen scales. At about 36%, conc HCl is about 10 molar. Diluting it 1/10 by weight makes it about 1 molar, by 1/100 makes it M/10. Maximum error of about 20% if you assume it has a specific gravity (well, we are talking normality, not molarity here) of 1.0. So how did you end up being out by a factor of 2?
Supplementary questions:
1)Are you just being old fashioned using normality, or is it still conventional in your parts?
2)How come you are diluting conc HCl to get N/10? Has your lab no molar HCl? I had to because the local lab suppliers wouldn't sell me any molar HCl in case I was making bombs (honest) but the pharmacy where I get my regular medicines was happy to sell me half a litre of conc.
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Re: Of Acids, Titrations and fickle normality.

#23  Postby GenesForLife » May 01, 2010 6:41 am

It is extremely conventional in our very outmoded way of doing science, , but I agree, the volume/volume method of dilution is remarkably streamlined.
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Re: Of Acids, Titrations and fickle normality.

#24  Postby rainbow » May 03, 2010 6:21 am

Oeditor wrote:1)Are you just being old fashioned using normality, or is it still conventional in your parts?

There is nothing 'old fashioned' about Normality. We use it often. It is a convenient measure.
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Re: Of Acids, Titrations and fickle normality.

#25  Postby GenesForLife » May 03, 2010 11:19 am

While it is convenient, Rainbow, in my field, in actual research (that isn't at the undergrad level) we use liquid-liquid dilutions (stock diluted to working solutions) which is ideal in the case of a liquid such as HCl
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