170 replies to this topic

[n5p29]

is the black one granite?
I also have seen the blue one somewhere before, but I can't recall it.

[Mbob61]

Are those crystals on the final one? Its a little hard to make out.
If not, i would guess something like Calcium Carbonate.
Also, bad times, i have left my old chem books at home so all this will be from memory

Mike

[Chyros]

scope, on 28 Sep 2010, 15:23, said:

If the blue one isn't copper sulfate, it's probably hydrated Copper Nitrate (anhydrous form is white)

Is the black precipitate Iron Sulfide? Is the first one Methyl Red?

It's a copper salt, but not copper nitrate . Copper nitrate is more of an extremely deep blue:

it's not a shade of green. This compound is darker and clearly has a bit of green in it.

The black stuff isn't iron sulfide, which is dark brown. This compound is a very very very dark purple - so dark that it appears black under most circumstances. In terms of colour it's probably the compound with the most concentrated colour I know of. Solutions of this are very strongly coloured even in extreme dilution.

The red one is indeed methyl red, correct .

Quote

is the black one granite?

No. Granite is a metal salt, true enough, but is a mixture of a lot of different things. This solid is pure.

Mbob61, on 28 Sep 2010, 16:55, said:

Are those crystals on the final one? Its a little hard to make out.
If not, i would guess something like Calcium Carbonate.
Also, bad times, i have left my old chem books at home so all this will be from memory

Mike

It's crystals indeed, but not calcium carbonate. This compound is chemically very different, as it is extremely soluble in water for example, but it is elementally comparable. It's not a calcium salt, but a potassium salt instead. Still, good guess - really white solids (i.e. not colourless but pure white) are very often calcium salts.

Edited by Chyros, 28 September 2010 - 21:37.

[Shirou]

Could post a video of yourself inhaling Sulfur hexafluoride. Should work wonders with your voice

Anyway for the last one I was thinking about is oxidised magnesium, but it doesn't really make sense to keep that stuff around I guess. Since you've already spoiled that its a potassium salt which would make me guess potassium chloride though I have never seen it in such crystalized form.

Edited by Shirou, 29 September 2010 - 10:02.

[Destiny]

If Chyros does it with helium I'm going to laugh myself to death

[deltaepsilon]

Ground up sherbet.

[Chyros]

Shirou, on 29 Sep 2010, 11:54, said:

Could post a video of yourself inhaling Sulfur hexafluoride. Should work wonders with your voice

Anyway for the last one I was thinking about is oxidised magnesium, but it doesn't really make sense to keep that stuff around I guess. Since you've already spoiled that its a potassium salt which would make me guess potassium chloride though I have never seen it in such crystalized form.

SF₆ is too expensive for me to just lift it from the lab - I'm not even sure we actually have it in our work group's storeroom (I'd have to check). Don't count on it though . Oxidised magnesium, in other words magnesium oxide, is a good guess, but it is powdery and doesn't appear in crystals like that. The colour of MgO is extremely white though, so you're not far off there. KCl IS crystalline, but has a cubic crystal structure that is basically identical to NaCl or kitchen salt. It is also slightly more transparent than this compound. Keep going though!

Destiny, on 29 Sep 2010, 12:02, said:

If Chyros does it with helium I'm going to laugh myself to death

We do have helium, but it's quite expensive . I'm not sure how I'd be able to get some of that .

deltaepsilon, on 29 Sep 2010, 14:42, said:

Ground up sherbet.

...no .

[Shirou]

Naturally school allowed us to burn magnesium ribbons for the bright light that comes off the slow reaction. It was that the sixth looked like it contained lots of those ribbons stuffed together in a container which is what made me think of it mainly.

On the SF6 well yeah I guess its quite expensive. May also be better to keep it at bay seeing how the shit is thousands of times more powerful a greenhouse gas than CO2. Dont want anyone on your roof after posting such a video xD.

Edited by Shirou, 29 September 2010 - 23:00.

[Destiny]

Wow Chyros, is helium really that expensive? Dang, if only hydrogen has those squeaky properties

[Chyros]

Quote

Naturally school allowed us to burn magnesium ribbons for the bright light that comes off the slow reaction. It was that the sixth looked like it contained lots of those ribbons stuffed together in a container which is what made me think of it mainly.

Heh, yeah, I suspected that already - the magnesium ribbon experiment is extremely common in high school. Good try though .

Quote

On the SF6 well yeah I guess its quite expensive. May also be better to keep it at bay seeing how the shit is thousands of times more powerful a greenhouse gas than CO2. Dont want anyone on your roof after posting such a video xD.

*looks at SF₆ molecule*

Hmmm, yeah, seems about right .

Destiny, on 30 Sep 2010, 4:21, said:

Wow Chyros, is helium really that expensive? Dang, if only hydrogen has those squeaky properties

Well, it's not as if it costs a fortune, but it's not as cheap as you would expect for something you can pull from the air. Yes, interestingly helium is very common pretty much everywhere in the universe you could be bothered to look, but it's quite rare on earth, comprising only roughly one half of a thousanth of a percent of the atmosphere by volume. Which is not a lot. Worse, you need some pretty rough techniques to refine it, since other atmospheric gases condense at -200 deg C roughly, meaning you need to put in a lot of effort to obtain it (ultracold fractional distillation).

To give some idea of the pricings:
He 57L canister, lowest purity - €190
SF₆ 227 g canister - €409

Perhaps if I look at the lab supervisor nicely I'll get some helium, got SF6 isn't gonna happen if I'm not gonna do a reaction with it .

[Chyros]

I'll give the solutions of the solids.



Methyl red was guessed correctly - it is a commonly used pH indicator when in solution, which is red in acidic and yellow in basic environments. The solid itself is also extremely red - such a pronounced colour is typical for azo dyes like this.
Copper acetate's bluish colour easily gives away that it's a copper compound as you guys quickly picked up, too. The acetate salt is IMO one of the most beautifully coloured copper compounds with its deep blue-green colour.
Ferrocene is the quintessential orange compound - orange solids are fairly rare, but this one is quite well-known and cheap. It's of high relevance in organometallic chemistry because it has very "standard" properties - a schoolbook example in OrgMetChem.
Potassium permanganate is one of the most well-known chemical compounds, since everyone has to to titration in high school and the titrant is almost invariably a solution of this. Even very dilute solutions have a deep purple colour, and the solid is so dark purple that it appears black. I'm sure a lot of you secretly knew this one .
Nickel bromide is the hardest to guess here. I couldn't find a picture that quickly, but it is a yellow-ochre compound, and as you can see, it appears speckled with light green.
Cobalt acetate - powdered in the pic, which belies its more crystalline colour - has a perhaps rather surprising colour for cobalt, which is traditionally more associated with blue. In truth, cobalt takes on quite a few colours, the red-pink colour being quite unique to cobalt (though cobalt chloride looks almost identical).
Tripotassium phosphate (pic not shrunk to show the crystal structure) is a fairly boring potassium salt, like pretty much any potassium salt. It's just very white and has a needley crystal structure.

I'm letting the question of why the NiBr₂ is speckled, stand, though. I'm sure you guys can work it out .

[deltaepsilon]

Ground up choc chips.

[BeefJeRKy]

Wow can't believe I didn't think of Potassium Permanganate! It was indeed one of the most used chemical compounds especially when we were learning Kinetics etc..

[Chyros]

Quote from LPTPW:

Chyros, on 29 Sep 2010, 0:17, said:

Destiny, on 29 Sep 2010, 0:10, said:

When he's done trying to stop messing with aqua regia

I use this fairly often actually ^^ .

And I wasn't lying - I present you my vid on aqua regia ^^ .



In case you are wondering, aqua regia is a mixture of nitric and hydrochloric acid. Th resulting acid is very powerful - even experienced lab practitioners avoid using this compound. Well, inorganic chemists do - for us synthetic organic chemists, it's not that spectacularly dangerous at all . Aqua regia is so corrosive that it can even dissolve some noble metals, notably gold and platinum. It is used a lot in the lab for cleaning certain pieces of glassware that have very persistent stains, or are otherwise hard to clean. Stirring bars are also commonly stored in aqua regia to clean them thoroughly. This vid tells of the use of aqua regia in the lab as well as other means of cleaning glassware / chemical destruction.

[Destiny]

Had a bit of comedic effect there, but it was enlightening Moreeeeeeee~







Also, what neutralizes bacon oil? Pouring it down the sink is rather...bad.

Edited by Destiny, 05 October 2010 - 15:46.

[ΓΛPTΘΓ]

Very interesting. Shame that I am more of a physicist than a chemist.

[Chyros]

Destiny, on 5 Oct 2010, 2:50, said:

Also, what neutralizes bacon oil? Pouring it down the sink is rather...bad.

You mean lard? Like anything, it's best to dissolve it first. Soap is capable of making many apolar and therefore water-insoluble compounds soluble in water because it has both polar and apolar characteristics, so some strong soap and hot water might do the trick. It you're looking for a bit more hardcore methods, washing petrol, turpentine or thinner will dissolve fats and oils in clothing for example, and if your drain is clogged up a saponification agent like sodium hydroxide (drain cleaner, basically) will get rid of it.

It's also probably better to put it in the toilet than in the sink .

NB: I should add that you shouldn't pour washing petrol or turpentine or stuff like that down the drain either . If you pour it down a drain, make sure it's not more exotic than soap.

ΓLambdaRhoTauThetaGamma, on 5 Oct 2010, 18:14, said:

Very interesting. Shame that I am more of a physicist than a chemist.

It's not too late to turn to the right path, young padawan . We have stuff infinitely more exciting than any of this ^^ .

Edited by Chyros, 05 October 2010 - 17:42.

[Destiny]

Soap...soap...we only have dishwashing agents here and I don't think mom will like me using body soap to wash the plate...

[Chyros]

Destiny, on 5 Oct 2010, 20:22, said:

Soap...soap...we only have dishwashing agents here

Any detergent will do - I won't believe you can't even have soap over there .

Edited by Chyros, 05 October 2010 - 22:02.

[Chyros]

Also, I'll give the answer for why the nickel bromide is speckled.

Nickel bromide or NiBr₂ is a so-called hygroscopic material. This means that it can pull moisture from the air and incorporate this into its crystal structure. Many many many everyday compounds are hygroscopic: kitchen salt for example. this will then form lumps and clog up your salt pot, so many people put in, for example, grains of rice. Rice is also hygroscopic and in fact more so than kitchen salt, preventing the salt from forming lumps.

In the case of NiBr₂ the absorbed moisture (three molecules of water per unit of NiBr₂) will actually change the molecular properties: you will get NiBr₂.3H₂O which is not ochre but light green. So the green speckles are NiBr₂.3H₂O formed as a result of the anhydrous (ochre) NiBr₂ being exposed to the moisture in the atmosphere for a while. If you left the container open for long enough, the whole top would turn green.

Edited by Chyros, 07 October 2010 - 16:17.

[BeefJeRKy]

I'll admit I suspected either hydration or some oxidation reaction.

[Generalcamo]

Can you demonstrate how much all the elements in group one of the periodic table react with other objects? I know sodium is one (Not the one in table salt)...

[Chyros]

Grand Kapitan Camo, on 15 Oct 2010, 0:27, said:

Can you demonstrate how much all the elements in group one of the periodic table react with other objects? I know sodium is one (Not the one in table salt)...

You want me to drop caesium in water . Not gonna happen mate, I'm not supposed to blow up stuff, let alone stuff that expensive . I use sodium metal quite often though, which I dissolve in methanol and then boil. Sodium's kept in jars stored under kerosene. I had a picture of one somewhere, but I seem to have lost it. I'll make another one tomorrow.

I can explain why they are so reactive though. I'll do that tomorrow as well, I'm really tired atm.

Here's a vid showing the effects of small amounts of alkali metals in water. They're all really reactive but some obviously more so than others. This particular vid is a lot more truthful than others you'll find - the well-known Brainiac one for example was faked.



One thing though: the sodium in table salt is sodium, just not elemental (metallic) sodium. The element is the same, the sodium in NaCl isn't a "different" sodium from just metallic sodium .

[Generalcamo]

Actually, table salt is sodium merged with chlorine, making it stable. You do NOT want to put pure sodium on your french fries, especially if there greasy...









EDIT: French fries? Or French Fires?

Edited by Grand Kapitan Camo, 16 October 2010 - 01:15.

[Libains]

Grand Kapitan Camo, on 16 Oct 2010, 2:15, said:

Actually, table salt is sodium merged with chlorine, making it stable. You do NOT want to put pure sodium on your french fries, especially if there greasy...

Almost complete fail in this statement. Chyros never said the sodium wasn't stable, he was just pointing out that the element is the same in both the pure metal, and the common table salt. the bonding with chlorine does produce the stability, however. And finally, putting pure sodium on greasy chips wouldn't be that much of a big deal - it reacts violently with water, and greasy chips are coated in oil, which is exactly what is used to keep sodium from becoming volatile (oil or kerosene). Sodium will react with water in the palm of your hand, however, but not to a degree by which you're likely to get more than slightly scalded - the entire metal needs to be contained in a reasonably large volumme of water to prove volatile on the levels that people expect of it.

Also, a quick point to note regards sodium form a biologist's perspective, you may want to check out this: http://en.wikipedia....%2B/K%2B-ATPase - without this pump nerves would not function and we'd all be well and truly dead. Never underestimate the importance of an element, just because it looks nasty on the surface