[langstonwf2]

if you place sodium in a container of water you will have a solution of sodium hydroxide right? and if you boil the water out will you have pure sodium hydroxide or will it evaporate along with the water?


also could you make small amounts of sodium from molten sodium hydroxide with out an inert atmosphere (small like a few milligrams small)

does anyone have a link of what molten sodium hydroxide looks like?

http://www.sas.org/E...hem/column.html This website makes making sodium seem easy is it really that simple?

-thanks

This post has been edited by langstonwf2: 19 June 2008 - 04:15 PM

[DrP]

You will be able to reduce it down to a white solid. Just to check (I'm sure you know this but just to be safe) the initial reaction is very violent! i.e. it explodes with enough sodium! It is (or was) a standard demonstration in schools as to the reaction of groupI metals with water.

[ChemSiddiqui]

DrP is right, it is a voilent reaction. but as per your suggestion it is true that sodium hydroxide is obtained. well to be exact, sodium hydroxide 'crackles' when you heat it and I actaully have never heard about the molten sodium hydroxide. Try Wikipedia, it might help!

[YT2095]

evaporating to dryness will likely result in Na2CO3 as the majority product unless you do this in an inert atmosphere also.

[langstonwf2]

what if i just let it naturally evaporate?

[YT2095]

even worse, sorry :(

[jdurg]

Yeah, sodium hydroxide is a CO2 magnet. It is why you don't prepare standard solutions of NaOH using old bottles of solid NaOH, or you don't make standard solutions ahead of time if the concentration is critical. All of the alkali hydroxides do a good job of removing CO2 from the air. I believe that most chemical CO2 scrubbers are KOH or NaOH.

[Ladeira]

DrP said:

It is (or was) a standard demonstration in schools as to the reaction of groupI metals with water.

It is. :cool:

[DrP]

Ladeira said:

It is. :cool:

Maybe in Rio - not sure if we can still do it here in the UK. I'm only going by what someone told me so I could be wrong, but I think the health and safety crowd put a stop to it. How can we check this out?

[hermanntrude]

here in newfoundland the schools aren't allowed sodium or potassium on site.

colleges are, though :) I could have rubidium and cesium if i wanted

[DrP]

You can have cesium but not sodium!!?!?! Whats that about then?!

[hermanntrude]

no no, I can have both. I work at a college, not a school, and that's why.

[Ladeira]

DrP said:

Maybe in Rio - not sure if we can still do it here in the UK. I'm only going by what someone told me so I could be wrong, but I think the health and safety crowd put a stop to it. How can we check this out?

Of course the demonstration Na + H2O is made by experienced teachers and inside a fume hood in Chemistry Technician schools (or college, I don't know how are Technician Schools named over there).
And those demonstrations usually come with phenolphthalein to prove the existence of Sodium Hidroxide.
I don't think it's dangerous since used the sodium is used in low quantity.

[hermanntrude]

Ladeira said:

Of course the demonstration Na + H2O is made by experienced teachers and inside a fume hood in Chemistry Technician schools (or college, I don't know how are Technician Schools named over there).
And those demonstrations usually come with phenolphthalein to prove the existence of Sodium Hidroxide.
I don't think it's dangerous since used the sodium is used in low quantity.

nevertheless, in some places it has caused accidents and has been banned in schools

[Ladeira]

who said is not here anymore =\

BTW, i've found a cool stuff (i don't know if the elements they used were really alcalyne metals (IA))...
http://www.youtube.c...h?v=85Q1ahrUgm8

[hermanntrude]

that video has been proven to be a hoax. It turned out they had explosives to cause the explosions, and caesium was not involved at all.

Actually, there is a website somewhere with videos of five grams of caesium and five grams of rubidium being dumped into water, and surprisingly they're not as violent as you'd imagine. This is explained by the fact that 5 g of cesium contains less moles of atoms than five grams of sodium or potassium, since each atom weighs so much more.

[John Cuthber]

I doubt that the Health and Safety people banned it.
http://www.hse.gov.uk/myth/
Paranoind shcoolteachers and/ or their lawyers might have put a stop to it.
Incidentally, re "that video has been proven to be a hoax."
Who proved it and where?

[Gilded]

John Cuthber said:

Incidentally, re "that video has been proven to be a hoax."
Who proved it and where?

There had been suspicions, and eventually it was confirmed by Sky TV:
http://www.badscienc...ening-standard/

[Ladeira]

hermanntrude said:

that video has been proven to be a hoax. It turned out they had explosives to cause the explosions, and caesium was not involved at all.

Actually, there is a website somewhere with videos of five grams of caesium and five grams of rubidium being dumped into water, and surprisingly they're not as violent as you'd imagine. This is explained by the fact that 5 g of cesium contains less moles of atoms than five grams of sodium or potassium, since each atom weighs so much more.

I was suspecting... It was very sensacionalist.

Well, i've never thought by this point of view... the explanation based on quantity of matter in this case was very interesting, as everyone thinks the same weight of cesium would make a enormous explosion.

[Ozone]

For critical drying and CO2 removal, eg. for conditioning GC carrier gas, etc. we usually use a layercake of LiOH and molecular sieves.

YT is correct, the carbonate is a problem even in very fresh mixtures and a small peak can always be seen when using it to match eluent with anion exclusion chromatography. This is a plus, however, when you want to know the precise carbonate content so that you can correct titrant concentration.

Another fine demonstration if to melt some lithium in a glass container over sand. Nice!

Terms like "risk management" and "ambulance chasing lawyer" have largely ruined the fine art of scientific demonstrations. Collapsing cans, colored fire and small explosions tend to gain attention a bit more readily than "computer simulations". Pity.


Cheers,

O3