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Homework Help: Colligative Properties

  1. Jan 10, 2007 #1
    How many grams of sucrose (C12H22O11) must be added to 552 g of water to give a solution with a vapor pressure 2.0 mmHg less than that of pure water at 20 degrees C? (The vapor pressure of water at 20 degrees C is 17.5 mmHg.)

    I tried it out, and this is my work.
    change in P=mole fraction*P in degrees
    2.0mmHg=X(17.5mmHg)
    X=0.11 moles

    552 g H2O * 1 mole/18.02g = 30.3 mol

    0.11(30.3 + x)=30.3
    3.33+0.11x=30.3
    x=245.18 mol

    245.18 mol sucrose * 324.34g/1 mol=83000
     
    Last edited: Jan 10, 2007
  2. jcsd
  3. Jan 10, 2007 #2

    Gokul43201

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