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Mass of a subsample.

  1. Oct 23, 2012 #1

    If I get 2.0830 grams of tobacco and add 1 gram of barium hyrdoxide to it. Mix it in 100 mL of chloroform:toluene mixture, I essential have a 100 mL solution right? Now I take a 25 mL aliquote from that? what will be the mass in grams of tobaco in that 25 mL sample?

    I thought simply 2.0830 x (25ml/100 mL) would do but my T.A. asked me to recalculate that because I did it wrong.

  2. jcsd
  3. Oct 24, 2012 #2


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    Staff: Mentor

    If you add these things to 100 mL of the solvent, you would have slightly more than 100 mL, so taking 25 mL would yield sample that is below 1/4 of the total. To be sure you can do it this way you would have to fill up to 100 mL with solvent.

    I don't see a way to correctly estimate the sample mass with the data given, as the final volume is not known and impossible to calculate.
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