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Homework Help: Chemistry Density Problem

  1. Aug 26, 2010 #1
    1. The problem statement, all variables and given/known data

    A technique once used by geologists to measure the density of a mineral is to mix two dense liquids in such proportions that the mineral grains just float. When a sample of the mixture in which the mineral calcite just floats is put in a special density bottle, the weight is 15.4448 . When empty, the bottle weighs 12.4631 , and when filled with water, it weighs 13.5441 .
    What is the density of the calcite sample?
    (Density of water at 25degrees = .9970g/ml)

    2. Relevant equations

    D = mass/volume
    mass of floating object = mass of displaced fluid

    3. The attempt at a solution

    15.4448-13.5441= mass of calcite? Not sure if that is exactly the mass of the calcite, but even so, don't know how to find out the volume of calcite. And what to do with the mass of the bottle filled with water?
    Last edited: Aug 27, 2010
  2. jcsd
  3. Aug 27, 2010 #2


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    Gold Member

    The bottle, when empty, has a mass of 12.4631. When filled with the dense fluid, it has a mass of 15.4448. Therefore, the mass of fluid in the bottle is 15.4448-12.4631=2.9817.

    You can do the same thing with the water to work out the mass of water that will fill the bottle.

    You are given the density of the water, so based on the mass you can calculate the volume of the bottle. You can then use this volume to calculate the density of the other fluid.
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