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Homework Help: Dilution Question

  1. Sep 13, 2009 #1
    1. The problem statement, all variables and given/known data
    Addition of 2uL of 50mM NaCl to a 30 uL reaction gives a final NaCl concentration of ______ M.

    2. Relevant equations

    3. The attempt at a solution

    so because you add 2uL to 30uL, the dilution is (2 / 2+30) = 1/16
    Then I multiplied the dilution with the concentration for the new concentration
    1/16 x 50mM = 3.125 mM

    Finally, I converted the mM back to M
    3.125 mM (1mol / 1000mmol)
    answer = 3.125 x 10^-3M

    does this look ok?

    thank you in advance
  2. jcsd
  3. Sep 18, 2009 #2
    Looks good.
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