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Homework Help: Chemistry - Reaction in humid air

  1. Jun 20, 2010 #1
    1. The problem statement, all variables and given/known data

    Sulfur dioxide reacts with humid air to produce Sulfure trioxide. Find the chemical equilibirum.

    2. Relevant equations

    3. The attempt at a solution

    I wrote out that:

    SO2 + O2 + H2O(g) --> SO3 + H2O(g)

    And balanced, I obtain:

    2 SO2 + O2 + 2 H2O(g) --> 2 SO3 + 2 H2O(g)

    Is this the correct formula for the reaction of SO2 with humid air?
    I seem to find that the H20 doesn't react at all, it is basically endups as H2O at the end of the reaction.

    Thanks for letting me know if I'm on the right track.

  2. jcsd
  3. Jun 20, 2010 #2


    User Avatar

    Staff: Mentor

    If water is present on both sides of the equation in identical quantities, it cancels out. If its presence is necessary for the reaction, it can be treated as a catalyst, so you should write H2O above the arrow.

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