Sciencemadness Discussion Board

Containing Cl gas for long term storage

pepsimax - 30-7-2014 at 01:56

Hi, basic question here but I've never really worked much with gasses.

I'm wanting to trap a small sample of elemental chlorine for my element collection, what's the easiest way to do this? Working with the correct PPE/fumehood etc, is it as simple as filling up an ampoule then sealing? Could I generate some Cl, pipe it off safely to the container, maybe use a tube clamp on the pipe to dispense it accurately and fill?

Or is it just easier to buy a ready made sample.

MrHomeScientist - 30-7-2014 at 05:37

There's been plenty of discussion on this topic before. Search and ye shall find.

Of course it's easier to buy a sample. It will also likely be more expensive, and there's something to be said about the accomplishment of making one yourself. I made my chlorine ampoule simply by leading chlorine gas into it for several minutes to displace the air, then sealing. It's faint, but you can see the green tinge. Woelen has a good description of how he made his on his site. I also toyed with the idea of sealing a tiny amount of liquid chlorine in the ampoule, so that when it evaporates it would fill the container with an easily visible concentration of gas, but I never did go forward with that plan.

Zyklon-A - 30-7-2014 at 09:45

I tried liquid Cl2 as well.
If you do this, get a thick walled ampule, put about 5-10 drops of Cl2 (l) in it, wait for about 90% of it to evaporate, then seal it off. This will allow a little pressure to build, thus making the yellow more visible.

aga - 30-7-2014 at 13:24

Is Element Collection inevitable in chemistry, or are there ways to avoid it ?

Also, when you have a full set, is it possible to resist Using a sample when needed ?

[Edited on 30-7-2014 by aga]

HgDinis25 - 30-7-2014 at 15:15

Quote: Originally posted by aga  
Is Element Collection inevitable in chemistry, or are there ways to avoid it ?

Also, when you have a full set, is it possible to resist Using a sample when needed ?

[Edited on 30-7-2014 by aga]


That's like buying a computer and not want to have a Internet Browser in it ;)

MrHomeScientist - 31-7-2014 at 06:58

For me it was the other way around - I started collecting elements, then the chemistry hobby grew to support that. I started with thermite reactions to isolate pure(ish) metals, then really got interested in chemistry in general. Many of my projects are still focused on wresting pure elements from their compounds for my collection (see my current Nd-magnet experiments).

As for using my samples, it depends on how much I have :) I really, really, really want to throw my 1g of cesium into water, but it was also expensive and hard to find so I've resisted so far! I sacrificed half of my terbium sample to make a fluorescent green salt, which made a great video for my channel and was definitely worthwhile. I don't quite have the full set yet, but I'm closing in. About 12 more samples to go!

AJKOER - 31-7-2014 at 10:55

One could also try placing chlorine hydrate in a closed tube.

As I recall, upon heating the hydrate, chlorine gas separates out and condenses as a liquid in the cool end of the tube.

This would perhaps be a more visible effect then looking at the gas in a tube.

Some background on chlorine hydrate:

- It remains a solid in a open tube until 9.6 C, above which point it decomposes into Cl2 gas and Chlorine water with effervescence. It will remain as a solid in a closed tube below 28.7 C (or 83.7 F), see http://books.google.com/books?id=h4_zgw9DZ1cC&pg=PA103&a... .

- It can be prepared somewhat easily when gaseous chlorine (or liquid Cl2, see Patent 4,678,656 at http://www.google.com/patents/US4678656 ) is combined with water (or water containing ZnCl2,..) cooled in ice, or by mixing Cl2 gas and steam and cooling (see Patent 3,908,001 at http://www.google.com/patents/US3908001 ). The Chlorine hydrate separates out as almost white crystals.

- The cited formula for the hydrate is Cl2.yH2O where y is between 6.01 and 7.63 depending on its preparation path (see "VARIABLE COMPOSITION OF CHLORINE HYDRATESSYNTHESIZED UNDER VARIOUS CONDITIONS", link: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&a... ).

- A good discussion of Chlorine hydrate can be found in "A review of the oldest known gas-hydrate - The chemistry of chlorine hydrate", link: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&a...

xfusion44 - 6-8-2014 at 10:38

Quote: Originally posted by Zyklon-A  
I tried liquid Cl2 as well.
If you do this, get a thick walled ampule, put about 5-10 drops of Cl2 (l) in it, wait for about 90% of it to evaporate, then seal it off. This will allow a little pressure to build, thus making the yellow more visible.


How did you cooled down chlorine? Dry ice, peltier element? I wanted to try with CaCl2 + Ice bath, which should cool down to -40°C, but I dont have CaCl2 yet...

Zyklon-A - 6-8-2014 at 10:42

I used dry ice and acetone, kept the ampule in there for few minutes, while chlorine gas was pumped inside.
It took only several minutes to liquefy it, and it was probably the most fun I've had making an element sample.