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pinxsy
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[*] posted on 28-2-2012 at 22:05
dry ice


If dry ice which is CO2(s) mixed with water, explosion will occur, am i right?

If that is so, what will happen when carbon dioxide gas mixed with steam at high temperature? will carbonic acid be formed, accompanied with explosion?


[Edited on 29-2-2012 by pinxsy]
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Bot0nist
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[*] posted on 28-2-2012 at 22:17


Quote: Originally posted by pinxsy  
If dry ice which is CO2(s) mixed with water, explosion will occur, am i right?
[Edited on 29-2-2012 by pinxsy]


No! No explosion, only explosive decompression of the container, if it's confined! My thinking is that the water is a lot warmer than the sublimation point of dry ice, so it rapidly increases the dry ice's conversion into gaseous CO<sub>2</sub>. Since carbon dioxide in a gaseous state takes up much more volume than solid, dry ice. The rapid expansion will rupture a confined space, if the gas can't escape fast enough. This is not an explosion, or detonation.

[Edited on 29-2-2012 by Bot0nist]




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pinxsy
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[*] posted on 28-2-2012 at 22:36


OHhh! Thank u!
and how do u calculate the volume of the container needed to spare for this 'rapid expansion'?
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[*] posted on 28-2-2012 at 22:53


look up the density of carbon dioxide at STP and calculate out the moles of needed dry ice to fill said container. The most basic math in chemistry. I suggest you learn the basics like significant figures, unit conversions, and most importantly, stoichiometry!

[Edited on 29-2-2012 by Bot0nist]




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[*] posted on 29-2-2012 at 07:07


Quote: Originally posted by pinxsy  
If dry ice which is CO2(s) mixed with water, explosion will occur, am i right?


If you put a piece of dry ice in water, it just bubbles and makes fog. It's a classic spooky halloween / mad scientist effect that I use all the time. If you then confine it in a closed container, bad things happen as Bot0nist said above.

As for carbonic acid, I doubt what you suggested would work. Carbonic acid is formed from a solution of CO<sub>2</sub> in water and exists only in relatively small amounts. I would think that the high temperature and dispersed nature of steam would make the formation of the acid pretty unfavorable. Gases dissolve better in cold solution.
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[*] posted on 29-2-2012 at 07:21


almost shit my pants after reading that first post.
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[*] posted on 29-2-2012 at 08:55


Not to appear rude, but why don't you bother reading up on these sorts of things before posting or even watch a few YouTube videos. Even those who know jack sh*t about chemistry often know what happens when dry ice is mixed with water.

Also, you might want to check out the equilibrium between carbonic acid and CO2/water. The equilibrium lies vastly to the right.




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[*] posted on 1-3-2012 at 17:58


For the results of such an "experiment" check this out:

http://www.salon.com/2002/10/03/askthepilot13/




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[*] posted on 2-3-2012 at 08:09


Nice story, bit how can a block of frozen carbon dioxide meet this description; "And what to do, now, with an extra, sopping-wet bag of ice"??. It's DRY ice.



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[*] posted on 2-3-2012 at 11:34


Quote: Originally posted by Bot0nist  
Nice story, bit how can a block of frozen carbon dioxide meet this description; "And what to do, now, with an extra, sopping-wet bag of ice"??. It's DRY ice.


He thought it was regular ice.




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[*] posted on 2-3-2012 at 12:06


Apparently pure carbonic acid has only been formed in the lab (as of 1998) by
Quote:
"(i) high-energy irradiation of cryogenic CO2/H2O ice mixtures...and proton-irradiation of pure solid CO2..., and (ii) protonation of bicarbonate or carbonate in a new cryogenic technique..."
and it is apparently stable in pure form.
Quote:
"We report that Alpha-H2CO3 can be sublimated and recondensed without decomposition into CO2 and H2O... To examine the stability of H2CO3, we prepared a film of crystalline H2CO3 on a CsI window by sequentially depositing layers of glassy methanolic solutions of 0.1 M KHCO3 and of is similar to 2 M HCl in the form of droplets, then by heating in vacuo from 78 to 200 K to induce protonation of HCO3, sup - and removal of solvent and excess HCl. The infrared spectrum of the film recorded at 200 K is characteristic for Alpha-H2CO3 (Fig. 1, curves 1) ( 10-12). The high crystallinity of the film is indicated by sharpening of bands and pronounced bandsplitting ( 12). The HCO3, sup - was completely protonated, as indicated by the absence of the intense HCO3, sup - band centered at is similar to 1647 cm-1 ( 10, 12). The CsI window with the H2CO3 film was removed from the apparatus together with its holder by breaking the vacuum with Ar (99.999%), and it was then stored in liquid N2."


Carbonic acid in the gas phase and its astrophysical relevance. By: Hage, Wolfgang, Liedl, Klaus R., Hallbrucker, Andreas, Mayer, Erwin, Science, 00368075, 02/27/98, Vol. 279, Issue 5355

[Edited on 3-2-2012 by AirCowPeaCock]




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