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Homework Help: A problem in volumetric calculations in Chemistry

  1. May 23, 2017 #1

    Wrichik Basu

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    Gold Member

    1. The problem statement, all variables and given/known data:

    The density of a 2.05 molar solution of acetic acid is 1.02g/ml. The Molality of the solution is:

    (a) 1.14 mole/kg
    (b) 3.28 mole/kg
    (c) 2.28 mole/g
    (d) 0.44 mole/kg

    2. Relevant equations:

    3. The attempt at a solution:

    I tried it out very simply using unitary method:

    Molality is the number of moles of solute in 1000g of solvent.

    1.02g acetic acid has 1ml volume.

    So, 1000g acetic acid has 1000/1.02 ml volume.

    1000ml acetic acid soln. has 2.05 moles of the acid.

    So, 1000/1.02 ml has 2.05/1.02 moles = 2moles.

    This answer doesn't match with any answer. Where am I wrong?
     
  2. jcsd
  3. May 23, 2017 #2

    Borek

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    Staff: Mentor

    You need to calculate mass of the solvent at some point, don't you?
     
  4. May 23, 2017 #3

    Wrichik Basu

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    Gold Member

    Yes, true. A bit more....
     
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