pomegranate
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GA3 gibberelic acid Molarity v.s ppm, discrepancies and vagueness in stock from various purities
GA3 gibberelic acid Molarity v.s ppm, 90% 99% 100%(for base calculations) discrepancy of legitamate information on stock solutions, from different
purity ranges or brand names ect.
the data on the net seems to refer to 90% purity GA3 gibberelic acid, 1mg/ml is called 1000ppm
but there is supposed 99% available as well (whether it is 99% or 90%, i don’t know)
but when i worked out the Molarity of it.....
I gotta say i'm stumped though, because i calculated the mols of water in a Liter at room temp, then multiplied by avagadro's number to get the number
of molecules of water, then i divided it by a million and divided that by the calculated the molecules from the mols of GA3 in a so called 1000ppm
solution, .9g pure GA3 /1L H2O, and i got about 46.95ppm
I wonder why? I also calculated it so the molecules of GA3 were divided by the total molecules of H2O and GA3, instead of just the solvent, H2O, still
not close, about 46.95ppm (oh, so i actually realized the decimals that changed were the ones that were rounded off, so same number after significant
digits lol
Either way, i don't get it. ?
i don’t understand their definition of ppm and if they actually only use an unscientific standard which changes for every damned compound they use
arbitrarily !?.
is it me, what am i doing wrong, i’ll put up my math later when i redo it (i tried using different atomic masses from their +-x amounts compared to
the given mass for gibberelic acid and indidnit with water. i was also wondering about if the binding energy (i know not nuclear) of the molecule
could lighten it somewhat but i figured that was unlikely a relevant amount. i just forgot which values i went with but still i don’t think that
order of magnitude change is at all close, of course. i just mean that when i redonthe math, my ppm will likely be off a little.
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CharlieA
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ppm is just that: you yourself posted correctly that 1 mg per mL is 1 ppm. That is because 1mg in 1 mL (for aqueous solutions) is 1 mg per 1000mg.
ppm is independent of the substance dissolved. For dilute solutions, covert the mg(or g) of the substance in 1L of solution to moles and this is the
molarity. You don't need to know the moles of water unless you are trying to calculate the MOLALITY (molarity). For these calculations, you also don't
need to use Avogadro's number. If you have a basic chemistry textbook, it should have a chapter or large section defining the various types of
concentrations used to describe solutions. Good luck with your calculations.
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Metacelsus
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1000 ppm (as OP wrote)
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pomegranate
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and they mean of the 90% purity.?
so i would have to calculate for 99% and “100%”ideal ?
do they base it on the base compound or the industrial purity standard ? :/
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CharlieA
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So what's wrong with being off by a factor 10E3? It's just a SWAG!!!
I also have a problem with reading. I have 2 new pairs of glasses, 1 specially for reading and I feel blinder than ever!
Oh well; I guess this is just my birthday rant rebelling against the infirmities of old age.
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morganbw
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I think that this is added to water?
If you are after 1000 ppm that would be one gram to a solution made up with this included equaling one liter. This is with 100% by weight solute.
If you have a 90% by weight solute divide 100/90. That will give you the proportion to use to figure out how much of the acid to use.
Instead of using one gram per liter of solution you would use 1.11 gram per liter to equal 1000 ppm.
I think you are possibly overthinking this.
Good luck.
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pomegranate
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eh, maybe, but it seems so vague, because there is “rapid dissolve” which is likely not 100% pure and they say to do the same thing, 1g per 1L for
1000ppm. sigma aldrich’s first search term is 90% so idk, it’s all over the place. but sigma does list it is used between 0.01 and 5 mg/ml .
i had run calculations on my ppm error if .9g/L .9mg/ml was actually 99% or visa versa, it’s not a big ppm change but it doesn’t allow fine
tuning, ie: if the data is all over the place with people using the “fast dissolve” or “quick dissolve” or whatever, being at 90% (.9g
actual/L but listing their ppm as ideal 1g actual/L
i guess it isn’t going to be too fine tuned anyway, because my scale is +-5mg accuracy ?precision, so if i put 50mg on it could be maybe 1st
recalibrated and weighed and repeated twice and averaged. idk and divided in solution to 5 or 10 parts for later solutions
meh
[Edited on 4-3-2019 by pomegranate]
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