Random Thread #1

[Swede]

Flying Fish, I'd say you got damned lucky, really. I'm glad you hooked up with good people.

 

Part of my job is flying with a new guy probably 1/2 the time. Very, very few people know about my hobby. When I do bring it up,the vast majority give me a weird look and say "Blown anything up lately?" A couple were cool about it, and looked through some materials I always carry with me. Admittedly, these guys aren't science professors, but they are a typical cross section of society, and the sad truth is, they are ignorant or scared of chemistry in all its forms. Even if you don't mention pyrotechnics,

 

chemistry = drugs or bombs.

 

The worst part is, they assume "It MUST be illegal. It HAS to be, right?" Kind of sucks.

[flying fish]

I should admit that most of the people who've shown a serious appreciation for my hobby are the science-geek types. And naturally, I'm always surrounded by such people . I go to an engineering/applied science school, and all of the managers at my company are physicists and chemists...

[FrankRizzo]

LOL...I just watched an episode of "Systm" the other day on distillation using one of those cheap electric water distillation units. The guest, an attractive woman chemical engineer had a great quote.

 

The quote is @ 1:05 So true

 

http://www.youtube.com/watch?v=KoECuFZOrgw

[50AE]

Hehe, today I met with another chemical supplier, which is cheaper. The guy was very nice... He gave me +300 grams of barium carbonate for free, he said that it couldn't pass the screen and he was too lazy to crush it. I also bought a 1L bottle of nitric acid, 1kg of KNO3 and the rest is 1kg barium carbonate. Today I put stoichiometric ratios of carbonate and nitric acid and I'll let them for a week or two, to wait the nitrate to precipitate.

[Bonny]

Hehe, today I met with another chemical supplier, which is cheaper. The guy was very nice... He gave me +300 grams of barium carbonate for free, he said that it couldn't pass the screen and he was too lazy to crush it. I also bought a 1L bottle of nitric acid, 1kg of KNO3 and the rest is 1kg barium carbonate. Today I put stoichiometric ratios of carbonate and nitric acid and I'll let them for a week or two, to wait the nitrate to precipitate.

 

 

What is the concentration of the nitric acid? It has been recommended (for safety) to use about 25% conc when doing this rxn. Rather than stoichemic amounts, you are better off adding carbonate until the rxn stops (I always add plenty of extra carbonate) to ensure that all the acid has been consumed. Acid is something you do not want left over in your nitrate.The excess carbonate can be filtered out. To clean up the product it should all be dissolved , filtered and recrystallized. See here for more good info;

http://www.pyrosociety.org.uk/forum/topic/...__fromsearch__1

[50AE]

The acid has 58% concentration, didn't have any trouble though.

Yes, I know about the acid, I'll measure the acidity before processing it. I've also read the topic

Also, the carbonate won't be consumed instantly and I'll have to wait some time. So it's better to add some excess of nitric acid, because it may evaporate with time. When the time has passed, I could add some carbonate again, to kill the acidic pH.

 

By the way, on the KNO3 that I bought from this guy it's marked that a 10% solution has a pH of 6.2. The purity is 99.7%. Is this bad ? I'm thinking if I could disgard the using of boring acid.

Edited September 11, 2009 by 50AE

[Bonny]

The acid has 58% concentration, didn't have any trouble though.

Yes, I know about the acid, I'll measure the acidity before processing it. I've also read the topic

Also, the carbonate won't be consumed instantly and I'll have to wait some time. So it's better to add some excess of nitric acid, because it may evaporate with time. When the time has passed, I could add some carbonate again, to kill the acidic pH.

 

I have done this several times and the carbonate is consumed not instantly, but very rapidly, with violent bubbling (add the carbonate in small amounts) . IMO there is no good reason to add any extra acid. ADD EXTRA CARBONATE rather than relying on testing ph to be sure... barium nitrate in solution can have an acidic ph.

[Mumbles]

0.8 pH points is not enough to reduce the need of boric acid. It acts as a buffer in addition to an acid as well. Heck, drinking water can get more acidic than that.

[50AE]

But my carbonate isn't consumed totally, most of it remains on the bottom of the container.

[FrankRizzo]

50AE,

 

I sounds like the carbonate you got was heavily contaminated with sulfate.

[50AE]

I doubt that. I mean, the carbonate is at least 99% pure. Also, it almost all of it has settled on the bottom. A guy who has synthesized barium nitrate before told me that I have to wait a week or two to let it dissolve completely.

[FrankRizzo]

On second thought, as Bonny said, the acid concentration is likely too high. Not from a safety standpoint, but from a chemical one.

[TheEskimo]

Anybody know what happened to cplmac2? I wish he'd do whistle rockets again; I love watching those beastly things on YouTube.

[Mumbles]

He's back around. He's been posting in the HE Section a little bit.

[skyisthelimitinc]

Youtube flagging!!

 

I dont know if this is off topic but i wanna talk about it anyway

 

I have quite a few rocket video´s on my channel, and it seems that there is someone trying to make problems with those videos, how can a rocket film be flagged as:

 

This video may not be suitable for minors!!!!

 

that mean in reality, you cant watch firework if you are under 18, and have to stay inside on new years eve or fourth of july, does this make any sense?

 

does anyone have a good idea how to upload normal firework videos without getting flagged?

 

skyisthelimitinc.

[TrueBluePyro]

yeah, its all pretty stupid and this has been talked about already really there is not much you can do. Here are a few things you can try while uploading you videos:

 

Dont name it as "Homemade firework".

Dont record the part where you light the fuse.

Dont post the formula, if someone wants the formula, PM it to them.

 

I think thats about it, its all pretty wierd and it all started happening to people at the same time, someone is just out there to get rid of the oyro videos....That is why we have pyrotube. Not as good, but your videos are safe.

 

-TBP

[skyisthelimitinc]

yeah, its all pretty stupid and this has been talked about already really there is not much you can do. Here are a few things you can try while uploading you videos:

 

Dont name it as "Homemade firework".

Dont record the part where you light the fuse.

Dont post the formula, if someone wants the formula, PM it to them.

 

I think thats about it, its all pretty wierd and it all started happening to people at the same time, someone is just out there to get rid of the oyro videos....That is why we have pyrotube. Not as good, but your videos are safe.

 

-TBP

Thanks TBP, ill go a head and edit some of the tags;)

[mike_au]

This afternoon I tried making CuCl2 to soak into some wood for coloured fire.

 

My plan was:

 

2HCl + CuO -> H2O + CuCl2

 

HCl has a molar mass of 36.4, CuO is 79.5 and my bottle of HCl says "300g/L".

 

So...I start with 450ml of acid which gives 135g or 3.7mol of actual HCl.

That should require 1.85mol or 147g of CuO to react completely yielding 1.85mol or about 250g of CuCl2.

 

When I added the CuO to the HCl it bubbled reasonably vigorously and produced a small amount of white precipitate. After adding over 160g of CuO there was still no sign of undissolved CuO and the mixture when dropped onto bicarb soda reacted strongly so I added a bit more, and more, and more...

 

I ended up adding almost 500g of CuO and it was still acidic. In the end I took a small amount of the mixture and neutralized it with strontium carbonate, that solved the immediate problem of getting the firewood soaking, but now I am wondering why it took so much CuO.

 

Have I stuffed up the equations (again!)? Obviously the bubbling and precipitate indicate some sort of contamination but surely that couldn't cause the amount of CuO required to more than triple. Could the acid be stronger than it claims (900g/L sounds a bit excessive so I assume this isn't the problem)?

[Mumbles]

HCl maxes out around 380g/L, and that is only stable at near freezing temperatures so it's not some super HCl you have. Your formulas all look right.

 

Ah the joys of inorganic chemistry. You see, transition metals are tricky things. There are few possible things going on here. Firstly, the white precipitate indicates the formation of at least a small amount of Copper (I) chloride, Cu2Cl2. They have different colors luckily enough in solution:

 

Cu (I) Chloride

http://www.phy.ohiou.edu/~chemclss/liquidCuCl.jpg

 

Cu (II) Chloride

 

http://farm3.static.flickr.com/2232/1507328635_5c137d3c5e_m.jpg

 

To make matters more complicated, it can form complex ions such as [CuCl4]2-, which is kind of a lime green color

 

http://www.woelen.nl/chem/experiment_with_cucl2.htm

 

Also, CuCl2 is naturally acidic, having a pH of 3.6 at a 0.2M soln. Next time just leave it after adding the appropriate amount of reagents, and evaporate.

[mike_au]

CuCl2 is naturally acidic, having a pH of 3.6 at a 0.2M soln.

 

Aah, that is probably my major problem right there. I guess I should invest in some universal indicator and research my products a bit better next time. I'll set up the left overs to filter for a day or three and then evaporate them and see what comes out.

 

Thanks

[FrankRizzo]

This afternoon I tried making CuCl2 to soak into some wood for coloured fire.

 

My plan was:

 

2HCl + CuO -> H2O + CuCl2

 

HCl has a molar mass of 36.4, CuO is 79.5 and my bottle of HCl says "300g/L".

 

So...I start with 450ml of acid which gives 135g or 3.7mol of actual HCl.

That should require 1.85mol or 147g of CuO to react completely yielding 1.85mol or about 250g of CuCl2.

 

When I added the CuO to the HCl it bubbled reasonably vigorously and produced a small amount of white precipitate. After adding over 160g of CuO there was still no sign of undissolved CuO and the mixture when dropped onto bicarb soda reacted strongly so I added a bit more, and more, and more...

 

I ended up adding almost 500g of CuO and it was still acidic. In the end I took a small amount of the mixture and neutralized it with strontium carbonate, that solved the immediate problem of getting the firewood soaking, but now I am wondering why it took so much CuO.

 

Have I stuffed up the equations (again!)? Obviously the bubbling and precipitate indicate some sort of contamination but surely that couldn't cause the amount of CuO required to more than triple. Could the acid be stronger than it claims (900g/L sounds a bit excessive so I assume this isn't the problem)?

 

By adding the sodium bicarb to the solution of copper chloride, you've ended up with a precipitate of copper oxychloride and a solution of sodium chloride.

[mike_au]

By adding the sodium bicarb to the solution of copper chloride, you've ended up with a precipitate of copper oxychloride and a solution of sodium chloride.

 

I wasn't adding the sodium bicarb to the solution (actually I did try that on a small sample to see how much it stuffed up the colour, and it stuffed it up pretty well).

 

I was dripping the solution into a pile of bicarb to see if it was still acidic (my crappy pH test strips don't work properly on a coloured solution).

 

I did use strontium carbonate to neutralize some of it at the end, so I guess I have copper oxychloride and strontium chloride.

 

Oh well, it was fairly green when I put a gas torch to it, so I think it will still turn out OK. Hopefully if I just boil off the rest of the mix it will work even better.

 

As a side note, I've been trying to figure out how CuCl2 has a pH of 3.6 (Where is the hydrogen?), and I've just realised I don't understand lewis acids :/ I wish I had paid more attention in chemistry class.

[Mumbles]

The water complexes with copper through the oxygen, which weakens the O-H bond, making the [H+] concentration somewhat higher.

[flying fish]

Here's an end-of-semester nighmare... Organic Chem test is tomorrow morning and I haven't even STARTED studying!!!

 

I've been so bogged down with other stuff that I haven't had time. This isn't the final exam... It's more like "Final A" ..."Final B", the real final, is next week. But screwing up this test could still seriously screw up my chances of passing, which would really suck since it's supposed to be my last term of undergrad and all.

 

The major topics and NMR/IR spec (determining structure/functional groups based on spectra), radical reactions, And some other various reactions that I can't even seem to remeber what they are at the moment. This is not good at all... How did it come to this, LOL? And why am I posting on the internet rather than studying?!

 

To make matters worse, I have another critical test in a math class that I haven't done one bit of studying for the following day. This is just not cool at all. I think I'm going insane!

[Richtee]

Here's an end-of-semester nighmare... Organic Chem test is tomorrow morning and I haven't even STARTED studying!!!

 

I've been so bogged down with other stuff that I haven't had time. This isn't the final exam... It's more like "Final A" ..."Final B", the real final, is next week. But screwing up this test could still seriously screw up my chances of passing, which would really suck since it's supposed to be my last term of undergrad and all.

 

The major topics and NMR/IR spec (determining structure/functional groups based on spectra), radical reactions, And some other various reactions that I can't even seem to remeber what they are at the moment. This is not good at all... How did it come to this, LOL? And why am I posting on the internet rather than studying?!

 

To make matters worse, I have another critical test in a math class that I haven't done one bit of studying for the following day. This is just not cool at all. I think I'm going insane!

Dude. You are one of the APPARENTLY most intelligent people I have had occasion to meet. You got this far- at one of the best schools in the country for a reason, and the reason was not luck. Suck up and git-R-done. I KNOW it's in there.