Sciencemadness Discussion Board - What is the COOLEST reaction you've ever seen/done?

What is the COOLEST reaction you've ever seen/done?

Hey There - 20-3-2014 at 15:16

Just curious

thesmug - 20-3-2014 at 15:55

Mercury thiocyanate decomposition with heat, thermite (FeO and Al powder). So hard to choose between the two!

gdflp - 20-3-2014 at 16:02

Pouring water on burning magnesium granules in a nickel crucible. The nickel gives the fireball a green glow!

copperastic - 20-3-2014 at 16:44

Probably baking soda and vinegar.
Just kidding Im a newbie to chemistry so probably zinc/copper oxide thermite its colored green but the smoke is zinc oxide particles so you dont want to breathe that.

bismuthate - 20-3-2014 at 17:00

BriggsRauchser oscillating iodine reaction (once using barium iodate which I may make a thread on) or some percipitation reactions such as such as FeCl3 and ferricyanides or Pb(NO3)2 and iodides.

Zyklon-A - 20-3-2014 at 17:53

Magnesium burning in chlorine dioxide.

bismuthate - 20-3-2014 at 17:58

Wouldn't that explode?

plante1999 - 20-3-2014 at 18:19

Yes, most certainly. I have doubts he even made chlorine dioxide.. It detonates for no reason.

Zyklon-A - 20-3-2014 at 19:31

Of course it exploded, that's why I said it's the coolest reaction I've ever done.
I filled a steel tube with a mixture of chlorine dioxide and chlorine, (probably made from sodium chlorite and chlorine, although I can't remember,) then I put a burning Mg ribbon in the pipe. Boom! it was quite scary but also fun.

elementcollector1 - 20-3-2014 at 19:44

Just made brass pennies today - not exactly explosive, but very fun to see the color change - although my partner kept insisting we leave the pennies on the burner for far too long, so most of them were burnt... Got 1 or 2 good ones.

Texium - 20-3-2014 at 20:02

I haven't done a whole lot of interesting reactions yet, although I do really like the NH4OH+CuCl2 reaction to produce Schweizer's Reagent. It's such a nice deep blue color and it's very satisfying to see, particularly when you combine the reactants together slowly!

DraconicAcid - 20-3-2014 at 20:07

I did the barking dog reaction once....carbon disulphide burning in nitrogen monoxide. I have my students toss hot steel wool into jars of oxygen every year, too, which is fun.

confused - 20-3-2014 at 20:32

The iodine clock reaction or the dehydration of sucrose with H2SO4

Brain&Force - 21-3-2014 at 10:19

Burning solutions of metal salts in methanol is always fun to do. But one of the coolest reactions I've ever seen is the stepwise reduction of vanadium by zinc amalgam.

The best reaction of all time is the sudden explosion between hydroxylammonium and bromate. I seriously need to try this myself.

Dissolving gallium in aluminum and drenching the amalgam in water is quite fun.

packetforger - 22-3-2014 at 11:50

Well, I always thought that burning magnesium shavings inside a block of dry ice was pretty cool.

Other interesting ones to note would be adding granulated sugar to manganese heptoxide, which "crackles" with little puffs of flame and thick "smoke" of MnO2 (don't inhale it!), magnesium ribbon wrapped in teflon tape, and the numerous thermites (exotic thermites thread on this forum is an excellent resource on those).

Zephyr - 22-3-2014 at 11:59

The coolest reactions I have performed are a boron thermite, the Briggs Rauchser oscillating iodine reaction, and the color change of neodymium chloride.

DraconicAcid - 22-3-2014 at 12:06

Quote: Originally posted by packetforger

Other interesting ones to note would be adding granulated sugar to manganese heptoxide, which "crackles" with little puffs of flame and thick "smoke" of MnO2 (don't inhale it!)....

I once made the mistake of trying to extract dimanganese heptoxide into dichloromethane- the reaction was similar (well, the billowing cloud of MnO₂ was, at least).

packetforger - 22-3-2014 at 12:44

Quote: Originally posted by DraconicAcid

I once made the mistake of trying to extract dimanganese heptoxide into dichloromethane- the reaction was similar (well, the billowing cloud of MnO₂ was, at least).

Did you perchance make the mistake of breathing it in? I was not expecting the billowing cloud the first time, and not wearing a respirator/breathing protection. Sore throat for days

Metacelsus - 22-3-2014 at 13:37

The reaction of aluminum and sulfur to form aluminum sulfide is probably the least cool reaction I've done.

[Edited on 23-3-2014 by Cheddite Cheese]

DraconicAcid - 22-3-2014 at 16:06

Quote: Originally posted by packetforger

Quote: Originally posted by DraconicAcid

I once made the mistake of trying to extract dimanganese heptoxide into dichloromethane- the reaction was similar (well, the billowing cloud of MnO₂ was, at least).

Did you perchance make the mistake of breathing it in? I was not expecting the billowing cloud the first time, and not wearing a respirator/breathing protection. Sore throat for days

No- this was at university, so I at least had it in the fume hood both times. (The first time was an accident; the second time was to show off.)

sasan - 24-3-2014 at 02:12

Reaction of Mg KMnO4 and a little sulfur!very fast and exotermic(flash powder)
If you have not try this,then try with these amounts: 7gr KMnO4 and 2gr Mg powder and 1gr sulfur
The more smaller the particles,fater reaction occurs,use less amounts,0.7gr permangenate,0.2 gr magnesium and 0.1gr sulfur,use sunglasses it will be very bright,more than sunlight!!!

forgottenpassword - 24-3-2014 at 04:33

Salt/ice is the coolest I have used at home. I hope to try CaCl2/ice sometime which supposedly gets down to -40C for use with a mercury diffusion pump that I bought.

packetforger - 24-3-2014 at 06:25

sasan - Permanganate flash is quite potent stuff, I would *not* advise mixing up big batches of it like that 10 gram batch. Still very cool stuff though, try iron powder and KMnO4, very very hot mix (sparks and hot fire, not "fast" like flash with my iron filings).

forgottenpassword - try a dry ice/acetone. Gets even colder than that

Zyklon-A - 24-3-2014 at 06:36

I just found out that Walmart and Kroger has solid carbon dioxide. Not sure if you can get it, but it's quite easy to find, and much colder than ice water with a chloride salt.
[edit: typo]

[Edited on 24-3-2014 by Zyklonb]

DraconicAcid - 24-3-2014 at 07:20

Oxidation of cyclohexanol to adipic acid using near-boiling nitric acid is also cool. Also a reaction to be done in the fume hood.

forgottenpassword - 24-3-2014 at 07:58

Quote: Originally posted by Zyklonb

I just fond out that Walmart and Kroger has solid carbon dioxide. Not sure if you can get it, but it's quite easy to find, and much colder than ice water with a chloride salt.

I'm sure I could find it somewhere, but how long would it last? I assume that I couldn't store it for any length of time. -40 C is not too bad and the ingredients are easily acquired and stored. I imagine that most reactions done at -78 C could also be done equally well at -40 C. Perhaps addition rates would have to be lowered slightly but that's not much of a problem.

Zyklon-A - 24-3-2014 at 08:04

Quote: Originally posted by forgottenpassword

Quote: Originally posted by Zyklonb

I just fond out that Walmart and Kroger has solid carbon dioxide. Not sure if you can get it, but it's quite easy to find, and much colder than ice water with a chloride salt.

I have not handled dry ice much, depending on the size of the block and where you store it, it should last for hours.
See this:http://www.eatbydate.com/other/dry-ice/

MrHomeScientist - 24-3-2014 at 09:19

If you have it in a well-insulated container as a large solid block (as opposed to small pellets), it can last a day or two. I've had success with a cooler packed with bubble wrap and taped closed with duct tape. Don't put it in a tightly sealed container of course, because of pressure buildup! I've heard it's a bad idea to store it in your freezer too, because the pressure increase can damage the fridge or pop the door open. Technically you can handle it without insulating gloves as long as you keep it moving around, but I really don't recommend it.

On topic, my favorite reaction of all time is the barking dog. I've done the 'real' version with carbon disulfide many times, but when the sulfur dioxide gas it produces started bothering my throat I switched to a safe version. It replaces the CS₂ with methanol and boric acid. This changes the flame color to green, and seems to greatly speed up the reaction too. Woelen and I talked about it in a thread somewhere, and credit to him for the idea.

nb198 - 24-3-2014 at 17:34

Quote: Originally posted by thesmug

Mercury thiocyanate decomposition with heat, thermite (FeO and Al powder). So hard to choose between the two!

Hey, I made a synthesis video about the mercury thiocyanate! Maybe you'll like it.

Link

[Edited on 25-3-2014 by nb198]

Brain&Force - 24-3-2014 at 18:57

Quote: Originally posted by thesmug

Mercury thiocyanate decomposition with heat, thermite (FeO and Al powder). So hard to choose between the two!

Really, FeO/Al thermite suits you? I'm into more exotic thermites, especially Al/MnO₂.

There's this one luminous clock reaction which is really unusual. I believe it was on the Periodic Table of Videos channel. I myself haven't seen too many cool reactions, but I'd like to burn ytterbium and samarium, produce reduced europium compounds, and perform the iodine clock reaction. Or better yet, invent a new type of clock reaction.

Of the reactions I have seen, I particularly like the chemical chameleon with peroxide and burning magnesium. Copper complexation is also quite interesting.

Zyklon-A - 25-3-2014 at 05:44

Copper oxide thermite, copper carbonate thermite and copper sulfate thermite (all with aluminum as reducer.)
Copper metal flash powder: 4Cu + KClO₄ → 4CuO + KCl.
I haven't done this one yet, but Botanist told me about it, and I will do it whenever I can get more copper sulfate. (To make copper powder: CuSO_4(aq) + Al → Al_{2[/sub(SO₄)₃ + Cu.)}

Texium - 26-3-2014 at 08:25

Quote: Originally posted by Zyklonb

I haven't done this one yet, but Botanist told me about it, and I will do it whenever I can get more copper sulfate. (To make copper powder: CuSO_4(aq) + Al → Al_{2[/sub(SO₄)₃ + Cu.)}

Yeah, we did a series of copper related reactions in chemistry class for our midterm lab, starting with copper wire, and eventually ending with copper powder by that method, except we used zinc instead of aluminum to replace it. That was pretty cool, and one of the reasons that I decided to start doing my own experiments. Even though I've always been interested in chemistry, that lab probably catalyzed my decision to do more than just read about it.

DraconicAcid - 26-3-2014 at 09:10

Quote: Originally posted by zts16

Does every college/university in North America do a version of that lab? I've attended two and taught at four, and I don't recall any college not doing that one...

Texium - 26-3-2014 at 09:46

Well maybe so, but this is in high school!

Steam - 26-3-2014 at 14:49

Probably the decompression of Iron Oxalate under heat, then poring out the pyrophoric iron!

or the reaction of bromine with aluminium!

Nitro-esteban - 5-4-2014 at 20:46

Probably burning potassium picrate or a mixture of ammonium perchlorate, charcoal, and sodium benzoate. For some reason it burns with a very bright yellow flame.

Oscilllator - 5-4-2014 at 21:11

The other day I ate some methylene blue. It turns your urine an incredible bright blue-green colour!

thesmug - 5-4-2014 at 21:29

How much, Oscillator?

sasan - 5-4-2014 at 22:18

Try CS2 vapors and N2O gas in a measuring cylender
Very beautiful and produce a very nice blue light

Mailinmypocket - 6-1-2015 at 05:50

The Beloisov-Zhabotinsky reaction can be absolutely amazing when done with exactly the right concentrations/dyes to make growing concentric rings. Disturbing the system with a toothpick causes entirely different patterns to occur almost organically.

kecskesajt - 6-1-2015 at 06:20

P-nitroaniline and hot H2SO4.

Mailinmypocket - 6-1-2015 at 07:24

I forgot about that one! Got some aniline coming so perhaps a small synthesis of p-nitroaniline is in order

careysub - 6-1-2015 at 07:52

Quote: Originally posted by MrHomeScientist

If you have it in a well-insulated container as a large solid block (as opposed to small pellets), it can last a day or two. I've had success with a cooler packed with bubble wrap and taped closed with duct tape.

The best cheap commonly available insulations I am aware of are foil-faced polyisocyanurate (PIR*) rigid panel, and expanded polyurethane rigid panel. I find the foil PIR panel cheaply in my local Box Box Hardware stores. It would be interesting to takes a sheet of this stuff, cut it up and duck tape it into a multi-layer dry ice box to see how long a standard dry ice block will last.

*Not an obvious acronym. I don't know why it is not PIC.

feacetech - 6-1-2015 at 16:36

Silver tree is quite nice

silver nitrate and mercury

j_sum1 - 6-1-2015 at 18:18

My students always ask for sodium and sulfur. PPE essential. Keep quantities very small (0.05g of Na) and grind in pestle and mortar. Makes 'em jump.

subsecret - 6-1-2015 at 19:19

Burning magnesium, manganese heptoxide and methanol, and decomposition of ferrous oxalate. I also test paint for lead (for my brother's projects), and I enjoy precipitating lead (II) sulfide with sodium sulfide, after the sample is dissolved in nitric acid.

unionised - 7-1-2015 at 05:14

The coolest reaction I did was when I was a student.
I prepared bis toluene chromium. Cr(C₇H₈)₂
The kit was mainly a large round flask surrounded by liquid nitrogen and containing a tungsten coil and connections so it could be heated by the passage of an electric current.

I placed a piece of chromium in the coil and evacuated the flask then started to leak a slow stream of toluene vapour into the flask- when it hit the walls it froze instantly.
I then connected the coil to a power supply and fed about a kilowatt of power into so it glowed white hot- not quite hot enough to melt the chromium, but hot enough that it sublimed into the vacuum.

On the walls of the flask the chromium and toluene co-condensed to form a greyish mixture.

Once the experiment had run for a few hours (during which my colleague and I poured several gallons of nitrogen into the cooling bath to keep it cool) I disconnected the power, and let the flask warm up again.
As the toluene melted it reacted with the chromium atoms that were stuck into the frozen matrix to produce the desired Cr[0] complex.

I'd say that the melting point of toluene -95C is pretty cool for working with individual Cr atoms.

[Edited on 7-1-15 by unionised]

Little_Ghost_again - 10-1-2015 at 15:38

Taking a solution of calcium chloride and adding conc sulphuric acid and watching calcium sulphate drop out snow white onto the bottom of the beaker, it was simple and easy but there was something about watching a solid of one substance start to appear from a liquid of another.

Youtube has a wealth of practical demonstrations

franklyn - 11-1-2015 at 00:14

http://www.youtube.com/watch?v=FofPjj7v414
http://www.youtube.com/watch?v=0KFAoqODZok
http://www.youtube.com/watch?v=hGn7aSe8e6w
https://www.youtube.com/watch?v=nadpcadav1I

I had the thought what would one of those color changing ' clock ' mixtures look like if it were to be made into a sudsey foam.

This is remarkable for the ease of preparation of a non-Newtonian fluid.
http://www.youtube.com/watch?v=_0J4dRqg7CE
Casein extraction from milk. Here's a thought, what about mixing this with the starch made above. Bullet proof properties ? Hmm.
http://www.youtube.com/watch?v=VFvik_THcNQ

.

Mailinmypocket - 11-1-2015 at 12:29

Quote: Originally posted by franklyn

http://www.youtube.com/watch?v=FofPjj7v414
http://www.youtube.com/watch?v=0KFAoqODZok
http://www.youtube.com/watch?v=hGn7aSe8e6w
https://www.youtube.com/watch?v=nadpcadav1I

I had the thought what would one of those color changing ' clock ' mixtures look like if it were to be made into a sudsey foam.

This is remarkable for the ease of preparation of a non-Newtonian fluid.
http://www.youtube.com/watch?v=_0J4dRqg7CE
Casein extraction from milk. Here's a thought, what about mixing this with the starch made above. Bullet proof properties ? Hmm.
http://www.youtube.com/watch?v=VFvik_THcNQ

.

I thought the oscillating foam idea was too cool to not attempt. The first attempt was a fail, it was the Belousov-Zhabotinsky reaction with ferroin as the indicator. On a test tube scale both reagents were prepared and in one tube was added half a drop of Sunlight soap. After mixing both reagents together the tube was sealed and shaken violently to create suds. The mix stayed red but did not change colors, it did however do the usual slow production of bubbles accompanied by the bromine odor.

Another attempt was done but this time using methyl cellulose to thicken the mix and hopefully get color changing foam. It seems to work. A lot of ferroin is needed to make the bubbles appear colored and foam is really hard to produce even by shaking the tube hard... (Methyl cellulose isn't soap after all) The color changes aren't very dramatic either. Now having had some success I'll try and tweak the mixes to see if something else works better and post some pictures or video! Neat idea Franklyn!

Sniffity - 18-1-2015 at 20:26

Done, as in personally done?

Sodium in water, methanol + dissolved salts (Emission spectrum, as a demo for my students). I also LOVE using Brady's reagent (2,4-DNPH) to detect carbonyl groups. And the classic elephant toothpaste!

Seen?

Decomposition of Mercury Thiocyanate, Barking Dog, Sodium + Chlorine gas, etc... too many!

Sulaiman - 8-2-2015 at 06:52

one of my favourites is 'thunderstorm in a bottle' e.g https://www.youtube.com/watch?v=Nyzlt-dVgWQ

easy to do and impressive for a small audience (family, friends etc.)

add a little of the permanganate at a time
use methylated/de-natured alcohol, acetone is too violent.

using the bottom 1/4 of a conical flask reduces splashing.

Hawkguy - 8-2-2015 at 12:01

I once made my friend eat a banana and drink a big ol' sprite. I'd recommend that one for sure. Before you do it yourself, first give your little siblings the opportunity to make a coin, and also so you see what it'll be like.