pHzero
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Unwanted Analytical grade (AnalR) chemicals
I've recently acquired a few analytical reagents. I don't really need such pure chemicals and I've heard that analytical stuff is pretty expensive and
sought after, so I was wondering if anyone in the UK's looking for any of the following:
NaCl, Sodium Chloride, 500g
NaCl >99.9%
Insoluble matter <0.003%
Acidity (HCl) <0.0018%
Alkalinity <0.05 ml N (nope, I dont get what that unit means either)
Bromide and Iodide <0.005%
... wait, there a really long list of tolerances, let me know if you want to know it.
I have one tub which is still sealed with shrink wrap, one which is opened and looks about 3/5 full and one which is opened and is about 1/5 full. I
cant be sure of the purity of the open ones.
NaHCO3, Sodium Hydrogen Carbonate, 1KG
It was sealed with a tamper-evident thing on the lid when I got it, but I stupidly opened it and broke it. I havent stuck anything in it though, and I
had the lid open for about 2 seconds, so its still pretty pure.
Acetic acid, glacial, 500ml
Opened, almost full
Tetrahydrofuran, THF, 2.5l, stabilised with 0.1% quinol
Opened, probably about 1/5 full, ie about 500ml left.
Sulfuric acid, H2SO4, 2.5l
Almost full. 98% conc. Opened
Xylene
500ml. Opened. Almost full
n-Heptane, 2.5l
Opened. About 2l left.
Methylbenzene/toluene, 1l
A little bit used, probably about 800ml left. Before i knew what analytical grade meant, I used this to damp some cotton wool, which probably
introduced some impurities.
With all of them, let me know if you want to know the limits of impurities or if you want to trade them for something.
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setback
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I'd keep em, especially the sulfuric. It's such a fundamental chemical, I could not imagine chemistry without it. GAA is also pretty useful. Just do
some more reading and start with simple reactions and lab procedures.
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pHzero
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I've got 5l of reagent grade GAA, so I don't really need the AnalaR stuff. As for the H2SO4, I thought I'd be able to trade it for something harder to
get hold of then get more by distilling H2SO4 drain cleaner, but actually I'm not sure that AnalaR H2SO4's worth that much, its probably cheaper than
the drain cleaner...
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MagicJigPipe
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Alkalinity is usually measured in mEq/L (mEq*L^(-1)) or mg/L (I do remember that). I have no idea what they mean by "N", though. A lower case n is
often used in equations to represent a number of moles but "N" should be newtons. Strange.
I'm not entirely sure. Is it how much acid (H+) must be added to a solution to reach a certain pH? We haven't talked about alkalinity at school yet
and I have barely heard of it elsewhere. Could someone perhaps give a brief explanation?
I would certainly buy the NaCl from you if the price was right. Unfortunately, however, I live in the U.S.
[Edited on 5-19-2009 by MagicJigPipe]
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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pHzero
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Quote: Originally posted by MagicJigPipe  | Alkalinity is usually measured in mEq/L (mEq*L^(-1)) or mg/L (I do remember that). I have no idea what they mean by "N", though. A lower case n is
often used in equations to represent a number of moles but "N" should be newtons. Strange.
I'm not entirely sure. Is it how much acid (H+) must be added to a solution to reach a certain pH? We haven't talked about alkalinity at school yet
and I have barely heard of it elsewhere. Could someone perhaps give a brief explanation?
I would certainly buy the NaCl from you if the price was right. Unfortunately, however, I live in the U.S.
[Edited on 5-19-2009 by MagicJigPipe] |
Hmm, I doubt it. You can't really measure acids in ml - 1ml of 98% H2SO4 would have a different effect than 1ml of 10% HCl, or 1ml of 10% HNO3 etc
etc.
I'd have expected the alkalinity to be expressed either as a pH or as a % OH- ions, or maybe equivelant %age of NaOH
Btw, the NaCl impurities list is attached
[Edited on 19-5-2009 by pHzero]
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MagicJigPipe
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Yes, you're right. I meant moles of H+ or H3O+, not mL of a certain acid, though. I thought the "ml" might be a typo. Who knows...
Another question I have that I've often pondered:
Which is correct "ml" or "mL"? I have always used mL because that's what I was taught and also because I always thought a liter was "L". However,
many very educated people still use a lower case "l". I personally don't like it because it tends to look too much like a capital "I" (unless you use
"ℓ" which I always tend to do when writing scientific stuff; so I won't mistake it for a capital "I"). Perhaps there is another unit that uses
a capital "L"? Almost certainly. But what is it?
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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pHzero
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ml's correct. The litre isn't named after someone, so its lower case. If a unit's named after someone, the name's lower case and the symbol's
uppercase. Eg, the joule (J) is named after James Joule, the volt (V) is named after Alessandro Volta, but the litre (l) isn't named after anyone.
We shouldn't be using litres any more, they aren't SI units. Really we should be using cm^3 instead of ml and dm^3 instead of l
I just thought though - maybe ml's an archaic abbreviation for mole?
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DJF90
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Abbreviation for mole is mol. ml and cm^3 are directly interchangeable (i.e. they are exactly the same thing) and so for many instances it does not
matter. When I have to write scientifically I will use cm^3, whereas when I am jotting something down for my own use it will be either notation, just
depends how I feel at the time.
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Lambda-Eyde
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MagicJigPipe: N (Normal) is very much like M (molar), except that it refers to ions instead of molecules or atoms.
In a base, N most often refers to hydroxide ions, so 1N NaOH = 1M NaOH. However, in acids it often refers to H+.
1N HCl = 1M HCl, but 1N H2SO4 = 0.5M H2SO4, because sulfuric acid is diprotic.
Edit: Confused moles with molar, fixed
[Edited on 19-5-2009 by Lambda-Eyde]
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pHzero
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| Quote: Originally posted by Lambda-Eyde | MagicJigPipe: N (Normal) is very much like moles, except that it refers to ions instead of molecules or atoms.
In a base, N most often refers to hydroxide ions, so 1N NaOH = 1M NaOH. However, in acids it often refers to H+.
1N HCl = 1M HCl, but 1N H2SO4 = 0.5M H2SO4, because sulfuric acid is diprotic. |
Ahhh I see... but what does the ml mean? A funny abbreviation for milli-?
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DJF90
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ml means milliliter. Have a look at a prefix table and you'll see what all the letters mean. of course they come before (i.e. are the prefix) to your
unit (eg J (joules), g (grams [note this is also non SI, but still widely used in the lab], l (liters)).
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pHzero
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| Quote: Originally posted by DJF90 | | ml means milliliter. Have a look at a prefix table and you'll see what all the letters mean. of course they come before (i.e. are the prefix) to your
unit (eg J (joules), g (grams [note this is also non SI, but still widely used in the lab], l (liters)). |
I know that's what it usually means, but it doesn't really work in this context... millinormals would though
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panziandi
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mL N means millilitres Normal:
The total alkalinity of a solution X is defined as the millilitres of 0.1000 N sulfuric acid required to adjust a specified volume of solution X to a
pH of 4.3. The sample volume should always be quoted. And before anyone asks 4.3 was chosen because it's outside the buffering range of normal
buffers. Whether this is EXACTLY what fits here I do not know but it certainly explains your odd units! I would guess its the ml N required to adjust
a N solution of teh sodium chloride to precisely pH7.0 (since sodium chloride should be pH7)
Anyway! Keep the AnalaR reagents, from the look of it they are quite old, either BDH or the company that BDH came from H&W. You may be able to
swap them with people, but despite the high purity they are old and of unknown origin / purity and you likely will only have offers of quite mundane
chemicals for exchange. Besides professional chemicals are SEXY and great for write ups! And highly reproducible results can be obtained. If you are
going to blossom with your hobby certainly keeping these chemicals would be most beneficial.
[Edited on 20-5-2009 by panziandi]
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