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Calculating Molal Boiling point elevation constant HELP!

  1. Jan 29, 2012 #1
    Calculating Molal Boiling point elevation constant!! HELP!

    So here's how I did my problem, but the answer I arrived with is wrong. I need help with this....:cry:

    Carbon disulfide (CS2) boils at 46.30°C and has a density of 1.261g/mL.
    When 0.250 mol of a nondissociating solute is dissolved in 400.0 mL of CS2, the solution boils at 47.46°C. What is the molal boiling point elevation constant for CS2?

    1. The problem statement, all variables and given/known data
    Normal Boiling Point: 46.3°C
    0.250mol of solute
    400.0mL of CS2 (solvent)


    2. Relevant equations
    ΔT[itex]_{b}[/itex]=k[itex]_{b}[/itex](molality)


    3. The attempt at a solution
    ΔT[itex]_{b}[/itex]=47.46-46.30=1.16°C
    molality = 0.250mol/0.400kg = 0.625m

    k[itex]_{b}[/itex]= ΔT[itex]_{b}[/itex]/molality.
    k[itex]_{b}[/itex]=1.16°C/0.625=1.856.
     
    Last edited: Jan 29, 2012
  2. jcsd
  3. Jan 29, 2012 #2

    Borek

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    Staff: Mentor

    Re: Calculating Molal Boiling point elevation constant!! HELP!

    Try harder.
     
  4. Feb 1, 2012 #3
    Re: Calculating Molal Boiling point elevation constant!! HELP!

    lol word

    piggy, you are given the volume and the density. you want to find the mass, so what do you do?
     
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