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Homework Help: Carbon dioxide from an antacid tablet

  1. Jan 16, 2012 #1
    1. The problem statement, all variables and given/known data
    Let’s say the % concentrations of CaCO3 (table 5) you obtain from trial #1 and #2 are consistent, while the concentration obtained from trial #3 is significantly higher. Demonstrate, how and where, a wet flask could be involved to explain such a result. Explain in great details.

    2. Relevant equations
    The equations under Calculations

    3. The attempt at a solution
    Alright, so we did a lab with calcium carbonate and antacid today, reacting each with HCl and measuring the pressure/temperature before the reaction and then after the reaction. From this we can find the volume, amount, mass, etc. I have no idea as to how to approach this question, it seems as it wouldn't depend on whether the flask is wet or not - because a wet flask with release more CO2 but how does that contribute to the final concentration of calcium carbonate in an antacid tablet? Any hints would be appreciated.
  2. jcsd
  3. Jan 17, 2012 #2


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    Staff: Mentor

    Wet flask will not release MORE CO2. CO2 will start evolving before you start to collect it, so you will not collect everything.

    Imagine you collected all of the gas and it was 44g of CO2 - how much CaCO3 was present?

    Now imagine gas started to evolve too early and instead of 44g you collected only 1g. Use the same stoichiometry to calculate how much CaCO3 was present. Is it a positive, or negative error?
  4. Jan 17, 2012 #3
    There would be a LOWER concentration of CaCO3 then! So the answer to the question would be NO, because if anything it would be a lower a concentration? Of course I have to back that up with reasoning + stoich. To answer your question, there would be 1g of CaCO3. What do you mean by postive/negative error?
    Last edited: Jan 17, 2012
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