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deltaH
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From the wiki of zinc nitrate:
| Quote: | Zinc nitrate is usually prepared by dissolving zinc in nitric acid, this reaction is concentration dependent, with a reaction in concentrated acid
also forming ammonium nitrate:
Zn + 2 HNO3 (diluted) → Zn(NO3)2 + H2
4 Zn + 10 HNO3 (concentrated) → 4 Zn(NO3)2 + NH4NO3 + 3 H2O
On heating, it undergoes thermal decomposition to form zinc oxide, nitrogen dioxide and oxygen.
2 Zn(NO3)2 → 2 ZnO + 4 NO2 + O2 |
Very interesting to see that ammonium nitrate forms!
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aga
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Sheesh ! How the f**k does that happen ?
I get it now. I've been lied to/assumed too much.
All these 'simple' equations are just a Summary of lots of complex reactions going on aren't they ?
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deltaH
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Yeah, basically because zinc is such a powerful reducing agent, it can reduce the nitrate ions into ammonia. The resulting zinc oxide then immediately
reacts with nitric acid to form more zinc nitrate and water. The ammonia immediately forms ammonium nitrate.
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Little_Ghost_again
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Quote: Originally posted by blogfast25  | | Quote: Originally posted by Little_Ghost_again | All I was asking was you said they got more interesting (faster), I wondered if you measured the increase of the reaction as you applied heat,
interesting and faster. You bang on about measuring and experimentation so i assumed you had measured how much faster the evolution of gas was for the
temperature applied.
Apparently not you just did what we all do  |
This outburst appears to be a sequel to another recent rant of yours, here and borne out of spite more than science.
'Banging on' about the need to measure where possible is entirely appropriate on a forum about science. We should ALL do more measuring.
And no, he didn't 'do what we all do': some of us do present actual measurements. You should be supportive of that, rather than show your
petty side, as you're doing here.
As regards aga's experiment on dissolving tin and zinc in HCl, its purpose from what I understand was to prepare the hydrated chlorides of these
elements, not to measure the rate of reaction. He noticed greater activity with the zinc than with then tin and concluded rightly zinc reacts faster.
No measurement was needed here, simple observation sufficed. But to actually measure reaction rate would of course require, well.. some measurement or
other.
So think about that for 5 seconds next time, before you shift into 'nene nenener' mode.
[Edited on 3-10-2015 by blogfast25] |
Your wrong, but somehow I get the impression the impression your one of those I would be wasting my time explaining too, I deeply respect your
knowledge and appreciate your help, but you sure can come across as an arse at times (with all due respect)
Dont ask me, I only know enough to be dangerous
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aga
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2 sides to that.
When people who Know have to repeatedly explain the same thing, i guess it becomes frustrating, and we're all Human here (well, mostly).
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blogfast25
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| Quote: Originally posted by aga | Sn -----------
Well, the Tin refuses to dissolve, and just keeps on clinking about in the beaker.
I feel sure i lost a few hours watching WATER boil off from the solution after the majority of the HCl had boiled away.
Adding fresh 20% HCl gives much finer bubbles, so too much heat was certainly a mistake.
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Remember that HCl forms an azeotrope, so after a while that's what you're boiling off. You CAN'T boil off the HCl and then be left with water.
When reacting something with an acid remember that it is the temperature that affects reaction rate, not 'how fast it boils'. The boiling point of the
azeotrope is constant so hard or slow boiling results in the same temperature and the same reaction rate.
It helps to do these things under reflux or partial reflux: just a simple hour glass can greatly reduce evaporative losses during the dissolution
phase.
I can't vouch for your Sn, but my 99.9 % cut into small pieces dissolves reasonably quickly in simmering 37 % HCl (12 M HCl).
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aga
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The reflux thing was added to the Sn experiment after a while, and seems like good sense.
Looks very much like i've bought 2 piles of metallic crap from ebay.
One was powdered Zinc, the other a solid bar of so-called 99% Tin.
The Bar is likely 60/40 Lead/Tin solder.
The Zn powder has something Other in there.
No idea what the Other could be, yet Instinct says to stuff the Zn powder into Toluene and see what happens.
I'll leave Positive feedback for them both, as i like this sort of thing.
Much more fun than it 'just works' - you learn more when it doesn't.
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blogfast25
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Just how wrong I am is illustrated by the messes you keep creating in your iodine thread. Keep wasting chemicals and deluding yourself you're learning
something. 
[Edited on 3-10-2015 by blogfast25]
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blogfast25
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| Quote: Originally posted by aga | The reflux thing was added to the Sn experiment after a while, and seems like good sense.
Looks very much like i've bought 2 piles of metallic crap from ebay.
One was powdered Zinc, the other a solid bar of so-called 99% Tin.
The Bar is likely 60/40 Lead/Tin solder.
The Zn powder has something Other in there.
No idea what the Other could be, yet Instinct says to stuff the Zn powder into Toluene and see what happens.
I'll leave Positive feedback for them both, as i like this sort of thing.
Much more fun than it 'just works' - you learn more when it doesn't. |
You're quick to jump to conclusions here.
Determine the density of your Sn bar, before claiming it's lead tin solder. With lead tin solder you should probably see some poorly soluble PbCl2
precipitate, during dissolution.
Density, easy method: http://oxfordchemserve.com/density-of-solid-objects-archimed...
Re. the Zn, are you sure of the quality of the HCl? Small amounts of Fe can manifest itself when you're boiling in, even is previously you didn't find
it.
[Edited on 3-10-2015 by blogfast25]
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aga
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Determining the Density of the Tin bar or the Zinc powder is painfully Obvious.
Yet i did not think to do that.
DOH !
Clear Thinkers Win again.
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blogfast25
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| Quote: Originally posted by aga | Determining the Density of the Tin bar or the Zinc powder is painfully Obvious.
Yet i did not think to do that.
DOH !
Clear Thinkers Win again. |
Seriously, try it. Fraudulent Fleabayers, IF that is what's happening here, deserve tar and feathers.
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aga
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Tar ?
I can make loads of that.
Any Organic Synth yields loads !
One of my dogs (alledgedly) has an affinity for feather production.
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blogfast25
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| Quote: Originally posted by aga | Tar ?
I can make loads of that.
Any Organic Synth yields loads !
One of my dogs (alledgedly) has an affinity for feather production. |
I suggest going through the 'proper channel' (in case of malfaisance) and not use your knowledge of the seller's address to serve 'rough justice'.
[Edited on 3-10-2015 by blogfast25]
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Little_Ghost_again
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| Quote: Originally posted by blogfast25 |
Just how wrong I am is illustrated by the messes you keep creating in your iodine thread. Keep wasting chemicals and deluding yourself you're learning
something.
[Edited on 3-10-2015 by blogfast25] |
noobs are meant to waste chemicals and make mistakes, but seems I am in good company! I might be able to salvage some of my mess, or I stand a better
chance than this
http://www.sciencemadness.org/talk/viewthread.php?tid=32782
Seems knowing it all and calculating the shit ouyt of everything is no guarantee afteral.
By all means have a go at my appalling technique but be careful thats one hell of a fall from a horse that high
Dont ask me, I only know enough to be dangerous
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blogfast25
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Keep the straw men coming and keep thinking you're scoring points that way: no one said anything about "knowing it all and calculating the shit ouyt
[sic] of everything being a guarantee".
You don't seem to realise just how illogical you sound here: it's not a guarantee, so that's a reason for not doing it? I seem to remember your dad's
a scientist, maybe you should ask him about that?
No one said anything about your technique either but in your iodine thread you seem to wilfully ignore advice from those who know how that reaction
works and w/o any worthwhile results.
You must truly despise Antoine Lavoisier, considered by many the father of modern chemistry and an obsessive when it came to measuring and recording.
[Edited on 4-10-2015 by blogfast25]
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Little_Ghost_again
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you are wrong again, i didnt ignore advice, I did the experiment then posted after it went wrong, i didnt have any H2O2, its not so OTC here. I tried
to follow a nurdrage video simple as that.
I have ordered more chemicals and when they arrive then I will try what was recommended. That still dosnt explain why I followed a procedure exactly
like it was done and got a different result.
I would love to have the resources and chemicals like some have, but I dont and I dont have the money to get many.
I used good quality acid and the iodide was from you so the assumption is seeing as I hadnt opened it then it is what it says on the tin (so to
speak).
I also figured nurdrage was highly thought of enough that his video would be fool proof. I got one to work (sort of) but low yield, the other I dont
know what happened. So it isnt the case of not following peoples advice, far from it
Dont ask me, I only know enough to be dangerous
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aga
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You did it different and not 100 the same i guess, or they missed out some important detail in the procedure (assuming everyone knows whatever it was)
which happens a lot.
Nurdrage is highly thought of. Lots of great videos.
No chemical reaction is totally foolprof.
I'm a foool, and have proven lots of simple procedures can easily fail in the wrong hands.
You really do seem to be taking all this too seriously.
So what if stuff goes wrong ?
So what if someone says something you dont like ?
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aga
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Sn----------
The Tin finally dissolved with the addition of some Nitric acid, although mild heating was also required to get a non-boring reaction rate.
Following the B25A method (blogfast25/Archimedes) the Tin bar density came out as 7.35g/cm<sup>3</sup> which is close enough to call it
pure.
The Tin is said to 99.24% pure.
There were some particles left after dissolution, so the liquid was filtered.
Gravity filtering is SLOW.
I'd switch to a vac setup, however the flow seems to continue so it will be left overnight.
Zn ---------
Looking up the ebay listing, no claim to Purity was ever made, and the Zinc powder was suggested for use in pyro applications.
Testing some powder with ethyl acetate did not get anything to separate (it was thought that some sugar or something organic was included).
Annoyed with the Brown sludge that had resulted from dissolution in 20% HCl, some NaOH was added (no LG2.485, measuring was not done here - this is
like poking different sticks at a frog to see if it jumps).
Immediately some cottage cheese formed, presumably zinc hydroxide, and friends.
This was filtered, and washed with water 3 times then dunked back into a beaker.
Adding fresh HCl brought back the brown/grey liquid.
So, it goes white/grey cottage cheese in Basic conditions and brown/grey liquid in Acidic.
What happens at pH 7 ?
Start adding the sodium bicarbonate (powder).
Lots of fizzing.
The bubbles carry with them a brown oily nastiness to the top of the beaker.
Eventually, at around pH 6, the solution begins to form solid granules at the bottom and a clearer yellowish liquid in the middle, with the brown gunk
as a froth on top.
Filtering yielded a yellowish clear liquid and a lot of white residue coated wth the oily material.
Yellow stuff will be boiled down tomorrow to see if it goes brown again.
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Little_Ghost_again
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| Quote: Originally posted by aga |
You did it different and not 100 the same i guess, or they missed out some important detail in the procedure (assuming everyone knows whatever it was)
which happens a lot.
Nurdrage is highly thought of. Lots of great videos.
No chemical reaction is totally foolprof.
I'm a foool, and have proven lots of simple procedures can easily fail in the wrong hands.
You really do seem to be taking all this too seriously.
So what if stuff goes wrong ?
So what if someone says something you dont like ? |
Yeah a couple of things hit a nerve and I reacted badly, for what its worth I sent an apology to blogfast. Nurdrage has two videos making iodine one
was the way I did it and the other used hydrogen peroxide. I really think I added too much water or not enough acid the first time, I should have kept
the liquid as I now think I could have saved it.
What I didnt count on was how bloody hard I found it to get into a container!! my gloves and jacket are black with the stuff, but despite this I did
get the iodine I needed. The real kicker however was the plate came up blank after all that lol.
Thanks for the voice of reason, and appologise all round for getting petty. I got touchy because I am just not good enough at the maths for this.
I love the experimentation but I am struggling with the working out side.
Congrats on the procedure by the way.
Dont ask me, I only know enough to be dangerous
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j_sum1
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| Quote: Originally posted by aga | Sn -----------
Well, the Tin refuses to dissolve, and just keeps on clinking about in the beaker.
I feel sure i lost a few hours watching WATER boil off from the solution after the majority of the HCl had boiled away.
Adding fresh 20% HCl gives much finer bubbles, so too much heat was certainly a mistake.
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Tin doesn't refuse to dissolve. But it does take some patience and persuasion.
I put a pellet of Sn in a test tube with some concentrated HCl and a tiny stir bar and it rattled around for a couple of weeks, but eventually got
there.
Implying that most of us are human, or nearly all of us are mostly human?
Just askin'
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aga
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All it needs is practice, same as Maths or anything else.
As you can see, i've failed with this Zn 'procedure' (if it can be called that) however you just need to keep marching on until it works, then you
Know How.
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aga
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There are some Humans here.
That's all i can say. The rest is classssified.
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blogfast25
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| Quote: Originally posted by aga |
Immediately some cottage cheese formed, presumably zinc hydroxide, and friends.
This was filtered, and washed with water 3 times then dunked back into a beaker.
Adding fresh HCl brought back the brown/grey liquid.
So, it goes white/grey cottage cheese in Basic conditions and brown/grey liquid in Acidic.
What happens at pH 7 ?
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It's likely that some of (all?) the brown stuff gets co-precipitated. When you redissolve, you're then back to square one.
[Edited on 4-10-2015 by blogfast25]
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aga
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DOH !
Oh well, not too much of a bother.
It's the SnCl2 i was really after.
The ZnCl2 was an afterthought.
Needs some actual Zinc as a starting material and not some mixed gunk.
Will still boil the pants off it tomorrow to see if it goes brown again.
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blogfast25
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| Quote: Originally posted by aga |
Needs some actual Zinc as a starting material and not some mixed gunk.
Will still boil the pants off it tomorrow to see if it goes brown again. |
Zinc battery cases? Nicely cleaned up?
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