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j_sum1
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Quote: Originally posted by Wizzard  | | Perhaps a light source with a special spectral characteristic to differentiate molten NaOH, molten NaO and molten Na? |
Care to elaborate?
What wavelength are we talking about here? How would this be set up? Are there sufficient differences at play here that you could use a regular
light with a gel filter? (We are talking home science here.)
Interested in what 420mLetc says on electrides and blueness observed.
There are a few videos I need to watch too.
I don't know when my next chance will be to get into the lab. Frustrating.
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Sulaiman
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When I did my quick test with sodium one of the transparent spheres 'jumped' off the filter paper onto the wooden table.
I didn't collect it because it was contaminated with wood / lacquer and was brown.
Assuming that I will 'catch' uncontaminated transparent spheres, e.g under oil.
What can I do to analyse the sphere?
even weighing it will be a challenge,
I could do a titration against very dilute acid (0.1 mL divisions on my burettes)
if I put the sample in water bubbles may indicate hydrogen due to unreacted sodium,
but I don't know how I'd analyse such a small quantity of hydrogen.
How would I look for other sodium/oxygen/hydrogen compounds?
I am clearly out of my depth here, HELP !
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j_sum1
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I am of the opinion that there is no sodium present at the stage when the sphere is transparent. Of course I might be wrong (which would make the
whole thing exceedingly interesting!) I think it is likely to be NaOH with possibly some Na2O. My analysis would be based on that assumption.
If you can catch it in a weighing dish (pre weighed) then you can get its mass. You could correlate this with the initial mass of the sodium. This
is another thing to be said for attempting a reaction in an inert atmosphere. If you can avoid burning off the sodium in air and avoid losses as
fumes and if you can capture the entire lump, then you could do some stiochiometric calculations based on having no losses. That could inform you on
whether there is Just NaOH or also some Na2O present. It will be a bit rough because there are a variety of other avenues for losses including
splattering into the air, and concentrated NaOH solution in the filter paper. The latter can be collected and analysed too if desired.
The next thing I would do is drop it into a conical flask containing some water and try to avoid splashes. Then you can titrate with an acid and that
should tell you how much NaOH/Na2O is in the lump.
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Morgan
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Have any attempts of a direct measurement been taken of this coulombic effect or is it even possible to measure it without destroying the effect?
Would saltwater work better or worse?
I was wondering if you put a needle or pincushion of needles on the surface of the water and ran a connecting wire through the bottom of the vessel
whereupon someone holds the wire to see if they detect any electricity in their fingers when a piece of NaK or Na is set or dropped upon the surface?
If it was saltwater I guess you could forgo the needles and just have some contact with the water or if it perchance was very high voltage tap water
might conduct well enough. Or is this a high amperage low voltage discharge? So many things to consider or facts to be aware of which would negate
this half-baked idea of test. Maybe there wouldn't be any current flow at all to the outside wire.
Tidbit on ohms.
"A Kelvin waterdrop generator might produce 20,000volts at 1/2 microamp. Dividing this voltage by this current gives 40,000,000,000 ohms, forty
gigohms. That's the line between insulator and conductor. Quite different than three ohms! So, if an object is to act as an insulator, its resistance
must be MUCH greater than forty billion ohms! For a Kelvin generator, a ten-megohm piece of wood will act like a dead short, a very good conductor. Is
it any wonder that a bit of surface moisture can convert an insulating object into a conductor? The highest value of resistor commonly available in
catalogs is 33 megohms, and most electrostatic devices will see this device not as an insulator or even as a resistor, but as a dead short."
http://amasci.com/emotor/stathint.html
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Kitsune1
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| Quote: Originally posted by Kitsune1 |
I happen to have some Lithium left over from a few months back which should be ideal for trying this out with. Hopefully I'll be able to find some
time tomorrow to do a few runs, will report back once done.
Really interesting video, a bit on the long side but the content does justify it. |
Just conducted the Lithium experiment multiple times; following the "Transparent Sodium" video as closely as I could.
All ten reactions were not dissimilar to the control (Li in water). It seems that this transparency effect might be limited to metals of a greater
reactivity than Lithium. It would be interesting to see this effect in slow motion with K and potentially Rb and Cs though arguably much more control
would be required to record any following effects.
A note, I also tried this with molten lithium but a thick passivation layer of oxide and hydroxide formed very quickly after coming in contact with
the water, thus obscuring the reaction.
Kit
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zed
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http://phys.org/news156104532.html
Might be transparent Sodium. Time will tell.
Pure transparent aluminum was created as a new state of matter by a team of scientists in 2009. A laser pulse removed an electron from every atom
without disrupting the crystalline structure.[3] However, the transparent state lasted for only 40 femtoseconds, until electrons returned to the
material.
A group of scientists led by Ralf Röhlsberger at Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany, succeeded in turning iron transparent
during research in 2012 to create quantum computers.[4][5]
[Edited on 14-3-2015 by zed]
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Morgan
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It just seems like when the charged spikes are forming you could get a wire in there on the metal and directly measure some sort of voltage spike on
the mass of metal when the reaction takes place with water. And if there is a high voltage discharge, maybe you could do something fun with it other
than watching an explosion. Would it be possible to bleed off the charge to create bolt of electricity?
http://www.nature.com/articles/nchem.2161.epdf?referrer_acce...
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Sulaiman
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my experiments with transparent sodium were delayed due to re-starting work after a long absence but I hope to have a go tomorrow or Sunday, so
assuming that I can collect say 1g of the transparent spheres, e.g. in oil
how can I determine Na, Na2O, NaOH etc. content ?
all dissolve exothermically in water to NaOH solution so I guess aqueous analysis is pointless,
suggestions please ......
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Morgan
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I wonder how well plain sodium would work compared to the NaK alloy if you preheated clean sodium in an inert atmosphere and then let it fall on some
water, so that it would be liquid and hopefully more "coulombic"?
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j_sum1
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Ok. I have been back through the videos cited. There are certainly some interesting observations there.
Thunderf00t has been really busy on this and what he has presented looks very sound: although his attention has been on the coulombic explosion of Na
and water without filter paper added. If you haven't seen his videos (cited by several others above -- the long one is best) then I refer to them
several times in what follows, so they may be worth a look.
Another thing I noted is that the original video has the transparent pellet sitting in a fairly deep puddle. When I did the experiment I had the
filter paper dry by comparison. Water was basically wicking through the filter paper to feed the reaction and there was very little liquid visible.
Similar observations however.
Here is a list of open questions. In no particular order.
What exactly is the composition of the transparent pellet?
By what mechanism does this pellet explode?
What is the reaction producing the visible flame?
What causes that flame to be extinguished?
What is occurring that causes the appearance of the pellet to go from dark (blue?) to glowing red to transparent?
Why does the pellet continue to float on water (in Thunderf00t's videos)?
I am both intrigued and convinced by Thunderf00t's observation of gaseous metal -- green in the case of potassium and blue for sodium. He also claims
that the burning is a reaction between the gaseous metal and steam -- which makes sense: especially if the flame has been observed in an inert
atmosphere. I have never seen gaseous metal before. It does seem strongly attracted to the lump of material. That would put the temperature above
760C for potassium, 883C for sodium and my guess is some lower temperature for NaK -- perhaps a kind of azeotrope. There might be a reason why the
gaseous material was observed more easily with NaK.
My guess is that the flame extinguishes when the amount of steam decreases and there just isn't the availability of reactants to sustain a flame.
That and the fact that the pellet cools a bit and there is not the same amount of gaseous metal present. At this point there is a thin film of liquid
metal coating a transparent pellet. This continues to react without a flame and eventually the transparent pellet is fully exposed. Possible
reactions for this include:
liquid sodium reacting with steam to produce NaOH / Na2O fumes and H2 gas
liquid sodium reacting with steam to produce NaOH / Na2O liquid that forms part of the pellet and H2gas that is expelled outwards
liquid sodium reacting with H2 to form a hydride
liquid sodium dissolving into the pellet
liquid sodium dissolving into the pellet and forming an electride solution (which would also account for the dark bluish appearance on the
surface)
Of these options My hunch is towards the first even if it is the most boring option.
The glowing red phenomenon might be due to Recalescence but I think it is just normal radiation due to the temperature. As it cools the spectrum
given off drops to the infra side of visible and the droplet is transparent in appearance.
As for what the pellet actually is, there are a number of possibilities.
I think it is basically molten NaOH. This is consistent with the temperatures assumed. Molten Na2O seems like too high of a temperature. Apart from
anything else, there would be a lot more gaseous metal if the temperature reached 1132C necessary to melt Na2O. I don't think there is sufficient
evidence to propose something exotic like transparent metal: however exciting that might be. In my experiment, splattered fragments of the pellet had
exactly the same appearance as NaOH once cooled.
There may be something dissolved in the NaOH however. Proposals in this thread include:
Na2O
H2O
Na
Na+ and e- (an electride solution)
Now we are talking about the reaction at the interface between the sodium and the liquid water on the filter paper. The critical element here appears
to be the inavailability of the water to react with the sodium. This is what distinguishes this experiment from the standard Na in water experiment.
I think there is cause for caution in making assumptions here. Thunderf00t observed the same transparent pellet without filter paper (and so water
more accessible) and noted that (a) atmospheric oxygen was not a factor. The reaction in the ampoule would have quickly used up all available oxygen.
(b) The pellet appears to be less dense than water since it floats. This might give cause to question some proposed compositions of the pellet.
H2O and Na2O are incompatible. deltaH has pointed out the incredibly high energy content of Na2O that is released on dissolution with water. This
might be useful for accounting for the later explosion. I see a continuum:
NaOH+H2O ----- NaOH ---- NaOH+Na2O
I had originally favoured the left side of this continuum: discounting the ability of Na2O to dissolve in NaOH, recognising the affinity that NaOH has
for water and noting that the stuff was sitting in a puddle of water. I am now more inclined to favour the right side of the continuum. There are no
observations that require H2O to be present and the Na2O has more explanatory power.
Which then leaves open what other species may be present.
The possibility of an electride solution is intriguing. (Nice video [url=http://www.periodicvideos.com/videos/liquid_electrons.htm]]here[/url.) I
just don't see the same observations however. I am on thin ground as far as my understanding of such things and I know little abut the required
conditions to form such species. My instinct is to dismiss such an idea for now.
Dissolved Na atoms is also an intriguing idea. I think both this and the electride idea are proposed to explain the explosion of the transparent
pellet at the end: by the mechanism of coulombic explosion. I think they fail in this regard.
The coulombic explosion described ably by Thunderf00t to explain the explosion of Na and water involved the build up of positive ions close together
on the surface of the liquid sodium and a corresponding build up of OH-ions in the water underneath it. When the repulsion force between these ions
of like charge exceeds the surface tension of the liquids present then there is a runaway acceleration that exposes new surface to the reaction.
Thunderf00t considers the rate of reaction to increase exponentially. I would propose that it is governed by a quadratic since the reaction is
occurring on a planar surface. Butt in either case it is not steady state.
The coulombic explosion is dependent on a number of factors. Unclean surfaces, and in particular oxide on the surface seems to inhibit this
behaviour. Addition of a surfactant also suppressed these explosions. And logically, there is a critical density of ions that must be present to
initiate the explosion. This density is unlikely to be reached if the free sodium atoms or ions are at a lower concentration dissolved in liquid
NaOH. I just don't see that coulombic explosion adequately explains the explosion of the pellet. Therefore I see little reason to propose Na or
Na+/e- dissolved in the pellet.
So the next question is what causes the transparent pellet to eventually explode? And, perhaps more critically, what prevents that mechanism from
occurring earlier?
To get an explosion there must be some kind of runaway mechanism where the reaction accelerates.
Na2O + H2O --> 2NaOH certainly releases a significant quantity of energy. However, I don't see how this can cause a runaway reaction. And I don't
see what might prevent this reaction from occurring until a critical point is reached.
Maybe the following occurs...
O2- + H2O --> 2OH-
These OH- ions would then repel and the Na+ ions in the transparent pellet would also repel. This could potentially cause the phenomenon observed.
And just like the coulombic explosion observed with regular sodium, this reaction needs for the repulsion forces to exceed the surface tension forces
for a runaway to occur. Wild speculation here of course.
This leaves the question of why the pellet does not sink in the ampoule that Thunderf00t experimented with. I have nothing to propose except the
leidenfrost effect and maybe some additional surface effects. Hot liquid NaOH in contact with water will produce some steam -- just because of its
temperature but also because the dissolution of NaOH when it occurs is exothermic and may also boil some water. I am not sure this is an entirely
satisfactory explanation. But it does explain limited contact between the pellet and the water and hence the delay in explosion and also the observed
buoyancy.
A couple more lines of investigation.
1.
It has been proposed (by me) that the chief difference that the filter paper makes is that the water is less available to the reaction. This causes
the reaction to proceed differently from the standard Na/water scenario. I think that this is a simplification. One of the things that I think
happens is that the sodium metal is now sitting in a very concentrated solution of NaOH in water. In the standard Na/water experiment the reaction is
Na + H2O --> NaOH + ½H2. I think that in a concentrated solution, some of the sodium may react with the sodium hydroxide:
Na(l) + NaOH(aq) --> Na2O(l) + ½H2(g)
I think this goes a long way to explaining why the same Na/water explosions are not seen. Remembering of course that unclean Na surface has been
shown to inhibit or delay the explosion of sodium in water.
I propose an experiment where a lump of sodium is dropped into a very concentrated solution of NaOH without filter paper present. My hypothesis is
that it will behave much the same way as the filter paper experiment.
(Concerning the experiment where Thunderf00t dropped NaK into an ampoule of water, I think that the reaction proceeded at a faster rate than the water
could diffuse the reaction products and therefore the metal was sitting in rather concentrated NaHO/KOH solution.)
2.
I think it is worth investigating the behaviour of liquid NaOH when it is dropped into (a) water, (b) a concentrated NaOH solution and (c) wet filter
paper. this will give some insight into what the transparent pellet is comprised of.
3.
Anyone equipped to observe the reaction between gaseous sodium or potassium and steam? I don't think it would be that helpful to describe what is
happening here but it sure would be cool to watch.
That's my thoughts for now. I don't know when I will get a chance to try this stuff.
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deltaH
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A test for the Na2O + NaOH hypothesis is simply to melt a mixture of those in a spatula and drop them onto water. This will also help to see if a
solution can be formed in the first place and to what concentration.
As for the presence of electride, the blue colour is indicative of that, but that is still a rather dilute electride (concentrated electrides are gold
in colour). It also appears to be transient, so to be honest, I don't think it's very important.
As for the coulombic explosion hypothesis, while very sexy, I'm not that convinced yet, especially after seeing the numbers for the heat of Na2O
hydration.
The safe money is on Occam's razor 
[Edited on 21-3-2015 by deltaH]
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Morgan
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First the transparent sodium coming into question and now the coulombic explosion possibly falling by the wayside. Maybe it's nuclear. ha
This morning before getting out of bed and not fully awake, I wondered if the NaK that was dropped into water forming the spikes, what else might be
causing the alloy to do that. Are there other examples of spikes forming in such a manner or something similar to draw upon for insight? Could you
suddenly put a high voltage charge on a drop of NaK and make it behave/spike similarly using a high voltage source?
When you look at this https://www.youtube.com/watch?v=LmlAYnFF_s8#t=15m58s it seems the metal is as flat as a pancake and even causing a concavity in the water at
T=0.3ms (right frame). So could it be at least entertained that some separation of the drop allowed water to break through the layer of metal and then
become superheated, jetting away in a needle/spike manner?
For some reason I thought of these examples of electrical discharge, just some left field associations
Making Electron Trees with a Linear Accelerator
https://www.youtube.com/watch?v=xoKloJwmLjI
2.5 million volts at 3,500 amps with a piece of acrylic
"Some specimens spontaneously self-discharge while being irradiated by the beam, causing bright flashes and bangs ..."
https://www.youtube.com/watch?v=9Po35g23fYI
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j_sum1
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There's something about the paper.
I am not totally unserious here. There are some very confusing things going on.
I have just spent an hour finishing off a bottle of sodium fragments and did about 30 or 40 trials with highly oxidised slivers of sodium ranging in
size from about 0.02 to 0.1 grams.
I have largely ignored the phenomenon of the transparent bead exploding. That is highly reproducible when the conditions are right. I have been
focussing on certain observations that always proceed the explosion. Namely:
The liquid metal sphere turning dark bluish almost black.
The sphere bursting into bright yellow flame
The flame extinguishing leaving a bead that may still appear black but quickly turns to glowing red and then to transparent
Here are some observations.
Filter Paper below the sodium
All above effects were observed consistently on wet filter paper.
The effects were observed when there was a puddle of liquid on the paper -- depth sometimes greater than radius of the sphere.
The effects were observed on damp paper without any additional water.
The effects were observed when the sodium was pushed through a perforation in the paper but was somewhat constrained by the paper edge.
Reaction with NaOH solution without paper
The effects were not observed on a glass petri dish containing concentrated NaOH solution. Several depths and concentrations were attempted ranging
from barely wet through to a deep dish. Concentration was in excess of 50% NaOH with some fresh prills of NaOH thrown in for good measure.
I think that is the end of that hypothesis.
Effect of plastic
The effects were observed with a plastic petri dish and moderately concentrated NaOH (maybe 25%) to a depth of 1.5mm. The sodium burst into flame and
burnt a hole in the plastic which prompted a change to glass.
Paper on top of sodium
The effects were not observed when wet filter paper was placed on top of the sodium. Again the amount of water was varied. On a couple of occasions
the sodium remained in the centre of the dish and fizzed mildly. This occurred both with just a damp paper and also with up to 5mm of water poured
over the top. Generally however the sodium skated around below the paper. The paper tended to balloon up with the H2 evolved. When the sodium made
it to the edge of the paper it did suddenly go dark and burst into flames. I did not see it go transparent the couple of times I saw this. (I did
crack a petri dish though.) The flame extinguished and left some unreacted sodium.
Submerged sodium
The effects were not observed when the sodium was submerged in a wide test tube of water and held there with a wad of steel wool.
The effects were not observed when the sodium was submerged in a test tube of water and held there by a wad of tissue paper. Instead, a bubble of H2
built up under the tissue paper and the appearance of the whole reaction was exactly the same as the standard Na on water.
The effects were observed when the sodium was sandwiched between a disc of filter paper and a wad of tissue paper and the whole thing submerged in a
test tube full of water. First a quantity of H2 built up separating the papers somewhat. Then I saw the pellet turn dark blue and burst into flame.
The fumes produced prevented me from seeing if the sphere had gone transparent. There was a bit of a pop but it was hard to say whether this was the
same as a small pellet explosion.
Add to this the intriguing observations made by Thunderf00t with his NaK in an ampoule. There were some obvious differences to the set-up:
NaK not sodium
No paper at all
Very small volumes
Very clean metal
Ampoule open to air but limited oxygen available in top of ampoule.
The additional observations from his experiment
Obvious green metallic gas
Blue seen after the flame extinguished. (I have observed this on occasions too.)
Transparent pellet floats on water.
There are a lot of things I cannot explain here.
Thunderf00t's claim that the flame is gaseous metal reacting with steam cannot be sustained. It seems that some oxygen availability is required. (I
am going to guess that some air was trapped in the test tube experiment I conducted.)
[edit]Maybe I should retract that. It appears that it is possible to get underwater flames with no access to oxygen at
all. See below. Which leaves me wondering why I did not observe the flame and the colour changes when the sodiumwas covered in a sheet of filter
paper.[/edit]
It seems that some kind of interaction with the paper is a contributing factor -- one that is not duplicated by glass.
A certain degree of contact with the paper seems to be needed -- something that does not occur when the paper is on the sodium but does occur when the
sodium is on the paper. Of course the NaK experiment puts paid to that generalisation.
So I am unsure exactly what reaction is taking place in the flame.
Then there is the blue which could be explained either by Na gas or by an electride. Both are intriguing. I am not sure how you would determine
which (if either) is correct.
And all this is before considering the transparent pellet, its composition and what makes it explode,
There is a whole lot going on here.
[Edited on 23-3-2015 by j_sum1]
[Edited on 24-3-2015 by j_sum1]
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j_sum1
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Just for fun.
Wrap a small clean piece of sodium in a tissue paper and twist it tightly. Submerge it in water. I used a wide test tube. Allow the bulk of the
paper to get wet before fully submersing to minimise the amount of air in the tissue.
Step back and watch the excitement. Underwater flames are always cool to watch.
(And it seems that I might have to modify some of my earlier thoughts.)
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deltaH
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I once did an experiment where I poked a wooden kebab stick into a small pool of very hot molten sodium hydroxide. A vigorous reaction occurs
producing a carbonaceous char and gas that is flammable with a yellow flame, if memory serves correctly? The wood is probably hydrolysing, but to
what exactly? Perhaps a retro aldol reaction is chopping up the cellulosic material into small flamable volatiles.
Perhaps something similar is going on here between the filter paper and hot molten bead.
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j_sum1
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| Quote: Originally posted by deltaH | I once did an experiment where I poked a wooden kebab stick into a small pool of very hot molten sodium hydroxide. A vigorous reaction occurs
producing a carbonaceous char and gas that is flammable with a yellow flame, if memory serves correctly? The wood is probably hydrolysing, but to
what exactly? Perhaps a retro aldol reaction is chopping up the cellulosic material into small flamable volatiles.
Perhaps something similar is going on here between the filter paper and hot molten bead. |
It's a thought.
But the paper seems to be relatively unscathed. I am drawing blanks whenever I think about it. Nothing I have come up with fits all the
observations.
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deltaH
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No, then that doesn't sound right, the wood definitely formed a lot of black char, so you would expect the paper also to blacken if this happened. The
water is probably cooling it sufficiently. Must be something else then.
[Edited on 25-3-2015 by deltaH]
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deltaH
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The plot thickens:
https://www.youtube.com/watch?v=PDRWQUUUCF0
Sodium chloride, WTF? Look at that shockwave, OMG!
What makes sodium chloride so special and not the other salts? I'm sad he didn't try molten sodium hydroxide, but I'm guessing that goes boom too.
I have a speculative hypothesis... the anion needs to be strong hard bases (HSAB theory). But, why does that matter?
While I think water is entering, mixing and superheating, I think there is more at play than just a physical process. Some kind of fast water
conduction (like fast ion conduction)? I wish this would be studied more because I think there is unusual phenomenon at play here.
[Edited on 11-3-2016 by deltaH]
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j_sum1
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Interesting.
Agree that NaOH would be a sensible salt to try. As would KCl.
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Pok
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I made a similar observation during the reaction of potassium with water a few years ago. I also thought of "transparent metal" but very soon I found
the explanation in the literature (Leidenfrost effect of molten KOH):
with photoflash only the smoke and the purple flame is visible:
When the flame extinguishes, the smoke formation also stops and a transparent little ball is visible which is running over the water:
detail of the ball:
another ball:
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j_sum1
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I get that Pok, but there are still a bunch of unanswered questions.
I am confident that the transparent bead is either molten NaOH or Na2O or a mix of the two. And I am pretty sure that some leidenfrost effect
prevents it from reacting immediately. I think the transparent bead explosion occurs when the bead cools somewhat and the leidenfrost effect
diminishes. And I think the "explosion" is driven by heat of dissolution when the bead contacts the water.
But still unanswered...
Why does this transparency phenomenon only happen when the paper is present?
Why does the sodium burst into flame with the paper present but this does not happen with water only?
What is the blue-black skin that appears?
And now, thanks to deltaH, what is going on that molten NaCl and perhaps some other salts interact with water in an explosive way that is not observed
with borax, sodium bicarbonate and other salts? I don't think thebackyardscientist's explanation is complete enough to account for the
observations or adequately describe a mechanism.
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deltaH
Dangerous source of unreferenced speculation
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Previously in this thread I had calculated that the heat released by a molten Na2O combined with hydration gives similar energy outputs as a TNT
explosion, so I thought this was enough to explain the bang, BUT
we observe a bang with even just molten NaCl, which leads me to believe that the explosion DOESN'T have hydration occurring, that happens slowly in
the prior step resulting in strong heating (the stage when the bead turns red?)
The explosion seems to be due pure to a later stage portion where the product is in very hot molten form. NaOH for the case of sodium, probably. The
chemical reaction stage doesn't seem too important, it might 'merely' be the engine that get's the final salt bead to a high enough temperature, i.e.
it's not that very high initial reaction heats that causes the explosion 
The main question, why the sudden detonation-like explosion at the end and why with certain molten salts only?
One very important observation thebackyardscientist makes is that 'just' molten salt isn't enough, it has to be very hot molten salt.
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Pok
potassium Prometheus
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I don't think that this is true. With potassium no paper is needed. The same for sodium (probably, haven't tried it).
| Quote: Originally posted by j_sum1 | | Why does the sodium burst into flame with the paper present but this does not happen with water only? |
The paper prevents the sodium from running away. The heat can build up locally so that the hydrogen (not the sodium) inflames. Maybe some sodium
vapour (which ignites) starts this reaction. This could be the reason why in the case of potassium there is always a flame visible (lower boiling
point).
@delta-H: why at the end? Because the Leidenfrost effect stops.
And concerning the NaCl/H2O explosion: the youtube video shows reference where possible explanations are given for the molten salt explosion. There is
alot of literature, e.g. here. It doesn't have anything to do with strong bases or so. Molten metals can show the same behaviour.
[Edited on 12-3-2016 by Pok]
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deltaH
Dangerous source of unreferenced speculation
Posts: 1663
Registered: 30-9-2013
Location: South Africa
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Mood: Heavily protonated
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Thanks for that literature Pok. It is very extensive, I think the answers I seek are probably there.
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MeshPL
Hazard to Others
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Has anybody tried to poke that sodium with a glass rod? Or in any other way? Or to pick it up using coffe grater? Or to dump liquid N2 on it? Or to
use ethanol or any other solvent with varying amounts of water? Or to drop sodium into an acid or something simmilar? (I realised I've never seen
dumping sodium into actual acid, only water and ammonia and alcohols. Reaction of Na with >90% HNO3 could be fun )
Edit: reactions of acids with sodium are not much more fun than reaction of water. There are some videos on youtube. Well, in one of them I've seen
slightly simmilar behaviour of sodium to the transparent sodium in Thoisoi2 video:
https://youtu.be/X_vMr-3P0KQ
But only with Na in 4M H2SO4. The sodium blob ignites and fizzes, than stops burning, goes dark gray and than pops, it kinda omits transparent stage.
[Edited on 12-3-2016 by MeshPL]
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