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Homework Help: Finding the Concentration of H3CO2 in a CO2+H2O reaction.

  1. Mar 8, 2012 #1
    1. Find the equlibrium constant if there is 0.030moles/L of Carbon Dioxide going in the forward direction and water is in excess to form Carbonic Acid (H2CO3)

    2. Relevant equations
    [products]/[reactants] = K

    3. The attempt at a solution
    I'm trying to figure out how Carbon Dioxide in the atmosphere will affect the chemistry of the oceans. From my research I've found that CO2(g) = CO2(aq) in water is 1.45 g/L where I deduced a equilbrium of 0.030 moles/L. My next step is where I have to figure out how much Carbonic Acid is made (CO2 + H20 = H2CO3) when I know that the equlibrium for the forward direction is 0.039 L/mol. So:


    which based on what I know translates to
    [H2CO3]/(0.03)[[H2O] = 0.039L/mol

    However, L/mol is not the same as mol/L and I need to find the concentration of [H2CO3] because after that I need to figure out the K values for H2CO3 = H++HCO3
    HCO3 = H++CO3

    *sorry, I do apologize but I'm not sure how to get the "reversible reaction" symbol on the physics forums, so I just used an "=" sign :wink:*

    ps. I was read on wikipedia that the solubility of Carbon Dioxide is 1.45g/L at 25 degrees C at 100kpa. The pressure, is that including the rest of the atmosphere? or just the carbon dioxide alone? because I've calculate the partial pressure of the CO2to be 11.6139 pa at sea level.
    Last edited: Mar 8, 2012
  2. jcsd
  3. Mar 13, 2012 #2
    Should I give anymore detail?
    More explaination?
    More of my working Out?
    was the layout incorrect?
    ... or do people just don't like me...
  4. Mar 13, 2012 #3


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    Staff: Mentor

    There are thick books written on the subject. Just carbonic acid is not enough to analyze anything, although you can be sure increasing partial pressure of CO2 lowers water pH. Google for seawater chemistry.
  5. Mar 16, 2012 #4


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    Last edited: Mar 16, 2012
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