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Homework Help: Finding Boiling point

  1. Jul 14, 2011 #1
    1. The problem statement, all variables and given/known data
    What is the normal boiling point in Celsius of ethyl alcohol if a solution prepared by dissolving 26.0g of glucose C6H12O6 in 285g of ethyl alcohol has a boiling point of 79.1 Celsius? Kb for ethyl alcohol is 1.22( Celsius x kg)/mol .

    2. Relevant equations

    26g of glucose Mole conversion.
    285 gram ----> kg
    Molality, m = mole/kg

    Equation = (Delta) Tb= Kb x m
    Kb is given. m is what I found.

    3. The attempt at a solution
    Mole of 26g glucose is 26/180g (molar mass)= .14 moles
    285g equals .285k kg
    .14 mol/.285 kg = .491 m
    Kb x m -------------> 1.22 x .491 = .599 Celsius
    Delta T: 79.1 celsius - .599 celsius = 79 Celsius

    My calculation has a rounding error? I'm close with the answer, idk what i'm doing wrong.
  2. jcsd
  3. Jul 15, 2011 #2
    Try subtracting 0.599 from 79.1 again.
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