newbchemist
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Lead acetate decahydrate?
Hey everyone
I recently tried making some lead acetate, and copper acetate.
I mainly did this to try and grow some cool crystals, but they also looked like interesting reactions. All the materials were easy to get, so it
seemed like a win.
The reactions were surprisingly active, and both were bubbling off small amounts of gas with the lead creating slightly more. I had watched a video on
the lead acetate, and there was bubbling in their reaction too. The author said it was likely oxygen trapped in the lead.
I was carrying this out in a small shack, and after a while I noticed a mild headache, similar to when soldering for extended periods. Yes, I goofed
up.
The lead reaction had begun to precipitate small white particles out, I'm assuming lead acetate. Also the shack had a heavy scent of acetic acid.
So the question is, what was happening there?
Were the lead acetate particles being ejected from the mixture due to over saturation and light bubbling?
Or, after some research, I found that lead acetate decahydrate has a very low boiling point, of around 20c. I was unable to find any other real info
on it though. Could the bubbling be from the decahydrate being formed and then immediately boiling? Is it even possible to create the decahydrate with
this reaction?
The lead source was fishing weights, and there were a few small black particles that were made as well. The temperature was a comfortable room
temperature. I'm not exactly sure, but it was probably higher than 20c.
Any insight is much appreciated.
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CharlieA
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What chemicals did you use?
What were their sources?
How did you carry out the reaction?
What is the literature reference that you alluded to?
Where did you find the value of 20*C for the boiling point of the decahydrate?
All in all you have omitted so may details of what you did and observed, that is difficult to formulate responses to your questions.
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andy1988
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So you're concerned about lead acetate vapor? I won't comment on your experiment (sorry no knowledge there), but here are some of my insights:
Selenium helps expel arsenic through multiple mechanisms [1] if you expect arsenic impurities in the lead (it isn't just lead vapor you should worry about when soldering, but trace amounts of arsenic/antimony too, in the ppm exposure ranges they're terrible). There is more literature on the matter you can search
for. Selenium yeast or selenite are fine ($2 at Walmart or pick up some Brazil Nuts).
As for the lead, read about Calcium Disodium EDTA. EDTA 'saturated' with calcium, without would be very dangerous to ingest (I don't recall if saturated is the right nomenclature, there may
be a different word for that context). Idea being this would chelate lead preferably over calcium. So... chat with a medical professional who
specializes in environmental medicine, they're far more qualified than I... but they may talk you into very expensive heavy metals testing which I
think is a racket in the U.S. (look at their tiered pricing! robbery!), far more costly than any "preventative" treatment (~$2 vs hundreds $$$), may
as well go on a medical tourism trip to somewhere with a nice beach.
Disclaimer: Content of my writing is intended to supplement, not replace, proper judgment. I disclaim any and all liability for your use of such
content.
EDIT: Selenium I bought, it was about $2.50 in store. Calcium disodium EDTA is also sold over the counter in tablet/capsule form (and powder). But to be
clear if in a form without the calcium it would chelate calcium in your blood too rapidly and risk heart failure (form you'd find in drain cleaner).
Calcium disodium EDTA is put in many food products such as mayonnaise as a preservative, it is generally recognized as safe (GRAS) by the FDA.
 
[Edited on 7-2-2019 by andy1988]
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newbchemist
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CharlieA, you are right. My mistake.
The reaction was between 5% white vinegar, 3% hydrogen peroxide, and some lead fishing weights.
I carried out the reaction by mixing a 50/50 solution of vinegar and peroxide in a glass jar, then adding the weights.
Also I was confusing melting point with boiling point. The decahydrate has a MELTING point of 22c. I am an idiot.
For completeness, I found the 22c melting point first on the lead acetate wikipedia https://en.wikipedia.org/wiki/Lead%28II%29_acetate#cite_note... referencing "Pradyot, Patnaik (2003). Handbook of Inorganic Chemicals. The
McGraw-Hill Companies, Inc. ISBN 0-07-049439-8", and also at the link https://tools.niehs.nih.gov/cebs3/ntpviews/index.cfm?action=...
Based on that it was likely just particles being ejected due to the small amount of bubbling? I figured that due to the high solubility of the lead
acetate, and the low concentration of acetic acid and hydrogen peroxide that all of it would easily dissolve. The solution should have been like 96%
water?
Andy1988, I was more just curious about what was happening. The EDTA page was a good read though, and I did look into some tests. Yes they are quite
expensive. I opted for some iron and zinc supplements, and a healthy diet.
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Ubya
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my solution also has this white precipitate, and if i remember correctly this happened also to other members of the forum
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fusso
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When I made Pb acetate, I used PbO from chem suppliers, not random fishing weights, and I got no white insoluble ppt. Not sure if the white ppt is
from As(impurity in commercial Pb)+H2O2=insoluble white stuff.
[Edited on 190207 by fusso]
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Ubya
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Quote: Originally posted by fusso  | When I made Pb acetate, I used PbO from chem suppliers, not random fishing weights, and I got no white insoluble ppt. Not sure if the white ppt is
from As(impurity in commercial Pb)+H2O2=insoluble white stuff.
[Edited on 190207 by fusso] |
i don't think it's arsenic, it's too much
anyway, when i'l filter the solution i'm going to do some test on the white precipitate
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Pumukli
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The standard potential of Pb is -0.125 V or about so it dissolves in vinegar even without the extra H2O2.
The dissolution of Pb releases (small) H2 bubbles.
You mixed in some H2O2 which either helped to oxidise the surface of the lead pellets or not. It may helped to accelerate the dissolution this way. I
suspect that a small part of the H2O2 was catalitically converted into O2 (and water). So some O2 bubbles could also be seen. (Of course, you could
not tell them apart from the H2 bubbles.)
The process surely produced some water soluble (= toxic) Pb2+ ions trapped in miniscule water (+ vinegar, H2O2) droplets. This is an unhealthy
reaction, because one can breathe in these small droplets.
How much did you actually breathe in?
Who knows. :-) Probably less than 1 mg Pb all in all. You will survive. Next time do such reaction in a hood or outside and don't intentionally smell
the bubbling mixture!
The white precipitate was probably the hydrolised lead-acetate, Pb(OH)2 or Pb(OH)Ac or something like that. Your starting vinegar was 5%, it was
diluted to roughly 2.5% - which is a fairly dilute acetic acid solution, and was diluted even more as the dissolution progressed. Pb2+ salts hydrolise
in plain water, if you try to dissolve them you would get a white, opalescent "milk"-like solution. This opalescens can be repressed and cleared by
adding some acid. The best acids for such a purpose are nitric or acetic acids because the Pb2+ salts of these acids have a high solubility.
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newbchemist
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Fusso, yeah I am regretting my choice of lead source.
Pumukli, that all makes sense. I don't think I took too much in, but I definitely learned a lesson.. assuming those brain cells survive the lead
poisoning that is.
Jokes aside, stay safe peeps. I'll never be running another experiment without proper ventilation and safety measures.
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Tsjerk
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That amount of white precipitate is not going to be As or Sb, it is zinc. Zinc is a common additive for lead, making it more mouldable.
Acetic acid by itself will make you feel dissy.
Thank you guys (fusso) for spreading chemo-phobia.
Edit: do you want a clean solution of lead? Filter of the precipitate.
[Edited on 7-2-2019 by Tsjerk]
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unionised
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| Quote: Originally posted by Tsjerk | That amount of white precipitate is not going to be As or Sb, it is zinc. Zinc is a common additive for lead, making it more mouldable.
Acetic acid by itself will make you feel dissy.
Thank you guys (fusso) for spreading chemo-phobia.
Edit: do you want a clean solution of lead? Filter of the precipitate.
[Edited on 7-2-2019 by Tsjerk] |
I'd bet against that for two reasons.
Molten lead and molten zinc do not mix.
That's how this works
https://en.wikipedia.org/wiki/Parkes_process
And also most zinc compounds are reasonably stable/ soluble.
I'd check to see if the white material is tin (IV) oxide.
[Edited on 7-2-19 by unionised]
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fusso
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What?! Why?? I don't understand:O
[Edited on 190207 by fusso]
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Tsjerk
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| Quote: Originally posted by unionised | | Quote: Originally posted by Tsjerk | That amount of white precipitate is not going to be As or Sb, it is zinc. Zinc is a common additive for lead, making it more mouldable.
Acetic acid by itself will make you feel dissy.
Thank you guys (fusso) for spreading chemo-phobia.
Edit: do you want a clean solution of lead? Filter of the precipitate.
[Edited on 7-2-2019 by Tsjerk] |
I'd bet against that for two reasons.
Molten lead and molten zinc do not mix.
That's how this works
https://en.wikipedia.org/wiki/Parkes_process
And also most zinc compounds are reasonably stable.
I'd check to see if the white material is tin (IV) oxide.
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Ok, fair enough. I had the same white precipitate when I were dissolving "lead". I thought it was zinc. But tin sounds more reasonable when I think
about it.
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andy1988
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Sorry if I did this, it wasn't my intention. I've been building a box fan to extract solder fumes from my basement and researching arsenic toxicity so
such stuff has been on my mind. I just thought that the selenium-arsenic metabolism thing was quite neat and saw an opportunity to mention it.
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DraconicAcid
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I've long loved the idea of doing liquid-liquid extraction using two molten metals, but it would probably still be possible to dissolve a small amount
of one into the other. Water and ether aren't miscible, but the ether layer of a liquid-liquid extraction still needs to be dried, since water will
dissolve in it to a concentration of a few percent.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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MrHomeScientist
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Back to the OP, whenever you react anything that produces a gas, an aerosol/mist of tiny droplets of solution is produced. You usually don't want to
be inhaling that, especially if your solution might contain especially toxic materials like lead. Don't worry about it in this case, because your
exposure was so small, but it might be wise to take better precautions in the future. Not only to protect your health, but also your equipment (from
possibly corrosive mist). A fume hood is always great if you can get one, of course, but even just capping the flask with a stopper or some paper
towels will eliminate that risk.
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j_sum1
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A little tip I learned from MrHomeScientist in one of his videos.
Whenever you are doing chemistry with lead, mix up a spray bottle of sodium carbonate solution. Spray all surfaces when done or even as you go. You
will render the lead harmless: PbCO3 is very insoluble. You will also find out just how far your aerosol has gone.
Not a substitute for a fume hood but a mask sprayed with the solution will protect your breathing.
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newbchemist
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That is good advice. I actually covered the top with a dry paper tower once I noticed it was more than just oxygen escaping. I did not however prepare
a sodium carbonate solution.
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phlogiston
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Lead carbonate can still become soluble in the acidic environment of the stomach.
I've also used the spray bottle method, but prefer to fill i t with sodium sulfate solution.
Lead sulfate is even less soluble than the carbonate, and should not redissolve even when ingested/inhaled.
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MrHomeScientist
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Great idea phlogiston! I used carbonate because I had a lot on-hand, but I'll switch to sulfate for anything in the future.
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AJKOER
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I would recommend inexpensive and widely sold Epsom Salts (a hydrate of Magnesum sulfate) as the most likely available reagent in place of Na2SO4.
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Also, the reaction of Pb with H2O2 and vinegar I believe is electrochemical in nature. Try adding a small amount of KNO3 as an electrolyte. You could
use less H2O2 by increasing contact with oxygen from air.
However, vapors rich in Pb could be even more of a problem especially using an air pump.
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Some points from prior readings with Lead exposure, a report from a teen helping his dad in breaking down Lead batteries suffering from 'brain fog'.
Young developing minds appear to be more sensitive to Pb.
Some sources suggest that Pb released into the environment is a problem and more research is suggested to understand pathways (see, for example, https://www.sciencedaily.com/releases/2008/07/080711125733.h... ). Other sources claim that dropping a heavy Lead weight on your foot is the more
serious threat! I personally after some experimenting (see http://www.sciencemadness.org/talk/viewthread.php?tid=71008#... ) with Pb have decided to avoid it.
[Edited on 12-2-2019 by AJKOER]
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