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Chromatography of River Water

Please help with the following problem.

Suppose that you must go into court and testify as to the level of X in the river water. Your lawyer is concerned that your analytical results are lower than they should be because you cannot extract with benzene (distribution Ratio K=4) all of X from your samples. Assume the concentration of X in the 1.00 L river water sample is 1.06 x 10-4 M.
(a) How many extracts would be required to remove all but 10,000 molecules of X from the sample with repeated 10.00 mL portions of extract?
(b) How about all but 1,000 molecules?
(c) How about all but 10 molecules?
(d) How many extractions are required for a 99.99% chance of extraction of the last molecule remaining (0.01% chance of a single molecule left behind)?

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Solution Summary

The following posting helps with chromatography problems. This solution provides step-by-step calculations to determine the number of extractions needed for different concentration fractions of river water. Step by step calculations are given for each.