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If you have chemistry questions....

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If you have chemistry questions....

squiggly 463 Replies 202,472 Views
Page 12 of 24 · Replies 221–240 of 464
#221
Hey squig
I am trying to create this formula

99.0 wt% as Na4EDTA•4H2O
83.2 wt% as Na4EDTA
64.0 wt% as H4EDTA

I have the Na4EDTA = also known as Tetrasodium EDTA and H4EDTA = Ethylenediaminetetraacetic acid.

Correct?

How many mg/liter of each do I add??
Will they both dissolve in water?
Should I mix them in their own solution and then combine them once dissolved?
thanks
 
#222
shaggyballs said:
I am trying to create this formula

99.0 wt% as Na4EDTA•4H2O
83.2 wt% as Na4EDTA
64.0 wt% as H4EDTA

I have the Na4EDTA = also known as Tetrasodium EDTA and H4EDTA = Ethylenediaminetetraacetic acid.

Correct?

How many mg/liter of each do I add??
Will they both dissolve in water?
Should I mix them in their own solution and then combine them once dissolved?
thanks
Click to expand...
This is a general chemistry question from hell

Why do you want to include both the hydrate and the dehydrated forms of the Sodium EDTA? That doesn't really make sense to me. Once you make a solution of the stuff its all going to be hydrated anyway.

Secondly, it is not possible to create a solution that is 99% w/w of one substance and 83.2% w/w of another. That would be 182.2% -- not possible.

You can make three separate solutions each with those w/w percentages and then mix them together--but that won't yield you a solution that is 99% X, 83.2% Y, and 64% Z.

Also these seem a bit suspect as a 99 wt% solution is extremely unlikely to be a solution. Here's why.

To make a 99%(w/w) solution you would take 99grams of your solute Na4EDTA•4H2O and mix it with 1 gram of your solvent (if water this is 1mL because water @ room temperature has a density of ~1g/mL). I can't think of anything of which 99grams will dissolve into a mL of water.

Get back to me when you figure out exactly what it is you need and I'll be happy to help.
 
#224
squiggly said:
​

This is a general chemistry question from hell

Why do you want to include both the hydrate and the dehydrated forms of the Sodium EDTA? That doesn't really make sense to me. Once you make a solution of the stuff its all going to be hydrated anyway.

Secondly, it is not possible to create a solution that is 99% w/w of one substance and 83.2% w/w of another. That would be 182.2% -- not possible.

You can make three separate solutions each with those w/w percentages and then mix them together--but that won't yield you a solution that is 99% X, 83.2% Y, and 64% Z.

Also these seem a bit suspect as a 99 wt% solution is extremely unlikely to be a solution. Here's why.

To make a 99%(w/w) solution you would take 99grams of your solute Na4EDTA•4H2O and mix it with 1 gram of your solvent (if water this is 1mL because water @ room temperature has a density of ~1g/mL). I can't think of anything of which 99grams will dissolve into a mL of water.

Get back to me when you figure out exactly what it is you need and I'll be happy to help.
Click to expand...
http://www.dow.com/versene/products/edta.htm
I think this is a powder or crystal form.
probably the reason for low moisture.
I would like to know what the ratio of Tetrasodium EDTA to H4EDTA = Ethylenediaminetetraacetic acid.

I will be using it for chelation and or early flush
 
#225
shaggyballs said:
http://www.dow.com/versene/products/edta.htm
I think this is a powder or crystal form.
probably the reason for low moisture.
I would like to know what the ratio of Tetrasodium EDTA to H4EDTA = Ethylenediaminetetraacetic acid.

I will be using it for chelation and or early flush
Click to expand...


You need to tell me what ratio you're looking for and I can tell you how to get to it.

H4EDTA is fine, the Hydrogens tell you it's an acid so there is no reason to write the whole name out.

You're not giving me enough information here.
 
#227
shaggyballs said:
I am trying to recreate a close version of the versene 220
I am unsure of the ratio of EDTA acid to EDTA salt to use for a pre-flushing agent.

more info here
http://www.dow.com/versene/products/edta.htm
Click to expand...


Looks to me like it's just EDTA, which is itself a chelant. You don't need to mix H4EDTA with Na4EDTA so far as I can tell. They've simply done the assay under different conditions because they molecule dissociates when it is in solution, and can be protonated (H4EDTA) when the pH is low.

In short, you're over thinking this.
 
#228
Made an account just to ask this: I am trying to do an isomerization of THC, however it requires ~18m sulfuric acid. Surprise surprise you can't just get this from the store. Do you know of a substitute for sulfuric acid that won't get the FBI wanting to search my anus for terrorists?

PS: It's nice to see another chemist who loves the plant.
 
#229
Timothy Craven said:
Made an account just to ask this: I am trying to do an isomerization of THC, however it requires ~18m sulfuric acid. Surprise surprise you can't just get this from the store. Do you know of a substitute for sulfuric acid that won't get the FBI wanting to search my anus for terrorists?

PS: It's nice to see another chemist who loves the plant.
Click to expand...


You really need a very strong acid like sulfuric for this process to work, HCl won't do the trick.

You can substitute phosphoric if you can get a hold of it, but that's more likely to get he FBI on your nuts (as phosphorous compounds play a bigger role in reactions which produce explosive agents typically).

So far as I know sulfuric acid is not on the homeland security watch list, you should be safe to pick up a concentrated solution on ebay/ioffer/something like that.

When doing this process please understand that the original synthesis you are likely reading from is working with a purified THC concentrate. To get the results you want it is important to purify your crude extract by chromatography (over silica).

I've been told it "works" without doing this, but you'll be doing an untested procedure in terms of reaction products.
 
#230
Head down to your local auto parts supplier. Sulfuric acid is used as battery acid.
 
#231
FYI: Advanced Nute's pH down is very strong phosphoric acid.
 
#233
I've got one for you. How does Drip Clean work chemically? Its label suggests it's derived from phosphoric acid (H3PO4) and potassium oxide (K2O) and works at very low concentration (0.4 mL/gal).
Is there a logical way these chemicals would reduce salt build up, or is H&G likely hiding its true composition from us?
 
#234
They will both exist in ionic forms in solution and will pull other ions out with them. The build up of ions is what eventually causes salts to build up by any number of pathways.
 
#235
squiggly said:
They will both exist in ionic forms in solution and will pull other ions out with them. The build up of ions is what eventually causes salts to build up by any number of pathways.
Click to expand...

Thanks for the help in understanding, but I don't quite. What's special about these particular ions? I feed my plants an ion soup every day - including K and P - but some we worry about building up while others clean up after them? I suppose it would make sense if it was to be used alone - as a flushing agent - but H&G says it is to be "administered at every feeding", so it's mixed in with everything else.
 
#236
cctt said:
Thanks for the help in understanding, but I don't quite. What's special about these particular ions? I feed my plants an ion soup every day - including K and P - but some we worry about building up while others clean up after them? I suppose it would make sense if it was to be used alone - as a flushing agent - but H&G says it is to be "administered at every feeding", so it's mixed in with everything else.
Click to expand...


It has to do with coordination chemistry. Sorry I can't get more specific than that, it's heady shit.
 
#237
Squiggly I ran across this and it made great sense to me and I have been conditioning my RO for about a year now and don't have the big swings in Ph anymore, is this info correct? oir is this wrong?

Thanks bro

How to buffer reverse osmosis water
Here is a great tip for those who use reverse osmosis water to buffer your water and help stabilize pH. There are two ways, both efficient.
- For those who prefer simplicity, all you have to do is add 20% tap water to your reverse osmosis water.
- For the purists who do not want to use tap water, or whose water is particularly bad, here are two easy steps:
1 – First increase your pH up to 10.0 with pH Up or potassium carbonate
2 – Then bring it down to 6.0 with pH Down
In both cases you’ll obtain water well adapted to hydroponic nutritive solutions, while avoiding untimely pH fluctuations.
You need to raise pH first because the “buffer” elements have a very high pH or very low pH. You can start by adding acid, but then you will need pH up to raise your pH.
You need to buffer R.O. water simply because pure water has no buffering capacity. It is subject to big swings in pH every time you add something to the solution, making it unsuited for cultivation. Using pure R.O. is a classic source of failure.

If you’re using reverse osmosis water, add 50-100 ppm of Cal/Mg; this helps to buffer your water so nutrients absorb better.

What happens is that the basic/alkaline components (mainly calcium) that are responsible for the high PH (as in 7.3 or 7.6) also buffer it together with the more neutral components. As soon as you add SOME acid, the basic elements neutralize it in 24 hours, but loose some potency, respectively get eliminated partially within the "reaction". If you repeat that process, the alkaline components- and their buffer capacity get lower and lower until the alkaline buffer is "gone". The "last" time you add ph-down/acid to your water, it will drop drastically to perhaps under 5. This mostly happens when a week PH down is used repeatedly. With Nitric acid at 75 or 95 %, this will not happen; it will get the alkaline elements down in one shot. But that is the stuff that burns through concrete floors like alien blood and it's truly not everyone's cup of tea.
PH of boiled water of 8.4 after 13 hours of boiling is "normal" because you evaporate lots of water, while calcium and other alkaline elements (already responsible for the high pH) remain in the water and hence will be present in higher concentration and push up the pH. There may also be some chemical reaction and transformation within these 13 hours of boiling, I don't know of.
Nutrients generally lower and buffer a certain pH, that's what any mineral composition with an acidic sum, added and dissolved in water does anyway. NUTRIENTS are actually made to lower the PH, as the usual 7+ is not suited. The only difference is that some manufacturers point this out explicitly while others don't. Some manufacturers may indeed add some more of specific components like mono potassium phosphate that helps lowering and buffering such Ph, but that's pretty much it. As a side effect (when running higher EC) you may have excessive Phosphorus that will result in Ca deficiency.
But in this context it is important to know that a higher nutrient concentration will lower the pH more than a weaker ratio. Hence in some cases it's not a bad idea to simply (slightly) increase the nutrient concentration by a click or two. It's also a reason why some manufacturers recommend higher concentrations as needed, and some commercial growers push the nutrient concentration higher.
If the PH of the base water is too high, most nutrients can't bring it down to around 6 and that's (only) where pH down- as in acids or other components are required. In ANY case it is always best to have, use or get water that is around and not (much) over 7.
RO water is fine, but take care what nutrients you use, as with some extra acidic nutrients (many are developed with areas in mind that have an excessive amount of calcium carbonate in the (well)water) you may end up with an unwanted but extraordinary low PH as well.
Attention, Ph and EC are interconnected; EC reading of a nutrient solution will not be the same at PH 5.0 as it is at 7.0!

 
#238
Thats sounds like a not to great idea woodsmeh^....just my .02
 
#239
My wife makes me drink baking soda and citric acid every morning.
It tastes terrible.
Is she trying to kill me?
 
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