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Homework Help: Need help with a topic discussed in class

  1. Apr 30, 2006 #1
    we were given this topic about soft drinks. The question is:

    Ideally, soft drinks are bottled under high pressures and are stored in a refrigerator in a closed container. Explain why these conditions ensure the best (i.e. least flat) beverage. Write an equilbrium equation in your answer.

    Any help would be appreciated.
  2. jcsd
  3. Apr 30, 2006 #2


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    Science Advisor

    The carbonation in soft drinks is due to Carbon Dioxide gas dissolved in the liquid, as the CO2 escapes from solution, the soda goes flat.

    The solubility of Carbon Dioxide in water (or any gas in a liquid for that matter) is influenced by the temperature and pressure. Gasses are more soluble in liquids at lower temperatures and at higher pressures.

    CO2 (g) + H2O (l) <---> H2CO3 (aq)

    When carbon Dioxide dissolves in water it forms Carbonic acid. Carbonic acid is not very stable and will decompose into Carbon Dioxide gas and water if given the chance.
    An equilibrium is established between the Carbon Dioxide above the liquid (out of solution) and the Carbon Dioxide which is dissolved in the liquid. Under higher pressures and/or lower temperatures, the equlibrium is shifted to the products side of the reaction (formation of H2CO3), and under higher temperatures and/or lower pressures, the equilibrium moves more toward to the reactant side (formation of CO2 gas).
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