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I need help interpreting my results for a thermal decomposition lab

  1. Oct 15, 2013 #1
    1. The problem statement, all variables and given/known data
    I performed an experiment recently, which required me to heat a flask and an unknown compound to constant weight. The unknown was supposed to be a mixture of calcium sulfate dihydrate and NaCl. My goal for this lab was to determine the % NaCl in the mixture. My percent error wasn't too bad: I got 12%. I'm just curious as to what could have contributed to this, especially since this error was consistent among the rest of my lab group. (Note: I was sure to completely transfer all of my compound to my flask). Does it have anything to do with the hydrate not being completely driven off?

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 16, 2013 #2


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    Staff: Mentor

    Composition of hydrates is often only approximate and depends on the temperature, humidity and sample history.
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