Text 2506, 54 rader
Skriven 2007-06-08 08:40:07 av Björn Forsström (2:203/614.61)
   Kommentar till text 2498 av Michiel van der Vlist (2:280/5555)
Ärende: Soda Streamer
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 BF>> All that pressure in a tiny plastic bottle....

 MvdV> As small bottle is stronger (can handkle a higher pressure) than a
 MvdV> larger bottle with the same wall thickness. And yes, that PET stuff is
 MvdV> very strong...

It sure is.

 BF>>>> There must be a very fast chemical reaction between the water and the
 BF>>>> carbon dioxide, otherweise the bottle would blow up, letting out all
 BF>>>> that pressure.

 MvdV>>> It is not a chemical reaction, but a physical one. CO2 is soluble in
 MvdV>>> water.

 BF>> OK, that's what I thought.

 MvdV> Both water (H20) and Carbon Dioxide (CO2) are polaric liquids. Both

You had me confused for a while here. H20 and not H2O....

 MvdV> molocules have a net electric dipole moment. So the one fits nicely into
 MvdV> the other.

Isn't it chemical then......?

 BF>> So the CO2 isn't compressed in the water?

 MvdV> Oh, it is compressed, what I meant is that the CO2 molecules fit in
 MvdV> between thge water molecules, so that they sort of take less space than
 MvdV> when they are in there together than they would, were they in seperate
 MvdV> bottles. But it is still under pressure. That is why the CO2 comes out
 MvdV> in bubbles when you open the bottle.

Ok, I'm starting to understand now.

 BF>> Is that why I have to add the taste after having cabonated it? When I add
 BF>> the taste there are CO2 bubbling so it almost flows over.

 MvdV> The taste (mostly sugar I guess) is not a polar liquid, therefore it
 MvdV> reduces the solvability of the CO2. When you add it, the solution
 MvdV> becomes over saturated and the excess CO2 boils off. That way you end up
 MvdV> with a new equilibrium where you have a saturated solution.

 MvdV> If you do it the other way around, it is more difficult to get the CO2
 MvdV> into the the solution in the first place and so you end up with less CO2
 MvdV> in it.

Sounds reasonable.
Thanks.

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