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Homework Help: Can someone check my work! (Hvap/Hcond Calculation)

  1. Dec 12, 2017 #1
    1. The problem statement, all variables and given/known data
    I don't have an answer key to these questions and it's my first time dealing with problems like this. so was wondering if my process is correct!
    upload_2017-12-12_23-51-13.png


    2. Relevant equations
    q = m*deltaT*C
    q = mols*Hvap

    3. The attempt at a solution
    So, my reasoning behind this work is that there was heat released from cooling and also heat from condensation. So, i found heat from cooling from the equation q = mdeltaTC = 2.53 J/gC * 30g * 9.5 = 721.05 joules = 0.72105 KJ. The heat heat from vaporization is just mols*Hvap = 48.221 KJ

    Added together = 48.221 KJ. Was wondering if this is correct?
     
  2. jcsd
  3. Dec 13, 2017 #2

    Borek

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    Staff: Mentor

    Logic behind looks OK, but why 30 g?
     
  4. Dec 13, 2017 #3
    i converted the 1.25 mol to mass with MM. is this correct?
     
  5. Dec 13, 2017 #4

    Borek

    User Avatar

    Staff: Mentor

    And what is molar mass of methanol?
     
  6. Dec 13, 2017 #5
    Gotcha. Plugged it into calculator. Should be 40 grams
     
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