Does agitation make gases dissolve faster?

  1. Why is CO2 released when soda is shaked, and dissolves again when the soda is stable?

    My teacher in class today said that soluble gases will dissolve faster in the presence of agitation. In practice (e.g. shaking a bottle of soda), this seems to not be the case. Please explain

    Thank You,

    EJ
     
  2. jcsd
  3. Not really sure ... but in could be that zones of different pressure are created in agitation. The ones with lower than "calm" pressure will ease the opposition of surface tension by bubbles. And the ones with higher should see no effect.

    I assume this is what happens when you hit a beer bottle from top towards the bottom than creates the well known beer fountain. While dropping a bottle on the table does not produce a similar effect at least in intensity.
     
  4. SteamKing

    SteamKing 9,420
    Staff Emeritus
    Science Advisor
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    The CO2 in a can of soda is kept in solution by pressure. When you open the can, this pressure is released and some of the CO2 comes out of solution and forms bubbles.

    http://en.wikipedia.org/wiki/Carbonation

    http://www.livescience.com/32492-why-does-soda-fizz.html

    Adding energy to the soda by shaking the can or tapping on the side will cause some of the CO2 to come out of solution. If the top is opened simultaneously when a lot of the CO2 comes out of solution, then you'll get a soda fountain. :surprised
     
  5. Ygggdrasil

    Ygggdrasil 1,663
    Science Advisor

    Agitation can make gasses dissolve in liquids faster, but this also means that it speeds up the reverse process: gasses coming out of supersaturated solutions. As SteamKing mentioned, opening a can of soda gives a supersaturated solution of carbon dioxide. Because carbon dioxide is above its solutility limit, it will come out of solution, and shaking helps this process occur more quickly. If you were opening a can of liquid which had been de-gased (and had no dissolved carbon dioxide), shaking this solution would help atmospheric carbon dioxide dissolve in the liquid until it reached its solubility limit.
     
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