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Homework Help: Chemistry recrystallization lab

  1. Nov 9, 2009 #1
    After performing crystallization and melting point determination I determined that my unknown solid was phthalic acid, however I am left with the question:
    At the end of the filtration of the purified solid, it was observed that a small quantity of fine colourless particles was contained in the filtrate that had been collected in a clean filtration flask. (vacuum filtration to separate crystals from solvent).
    i) What were these particles?
    ii) Explain why these particles formed in the filtrate.
    iii) Explain what effect, if any, the formation of these particles might have on the experimental results.

    I am thinking that these particles were either crystals that were so small that they passed through the filter, and this would then affect the experimental results as the yeld would be less, or that these are impurities, but if they are im not sure why they would form in the filtrate.
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Nov 9, 2009 #2


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    Staff: Mentor

    Filtrate is a saturated solution. Under vacuum it was most likely partially evaporated, and cooled in the process.

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