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Homework Help: Calculating heat change

  1. Feb 4, 2009 #1
    hey guys, I'm little stuck on this question: How much heat, in kJ, is released when 15.8 g CH3OH is condensed at 25C? (ΔHvap=38.0 kJ/mol)

    I know that the equation is: H= mΔT x SH, for change in temp.
    and the phase change: H=mΔV

    I have no idea how to set it up according to the given variables.
  2. jcsd
  3. Feb 4, 2009 #2
    Assuming the condensation occurs at a constant temperature you need your second equation only.You need 38kJ for one mole so you need to find out how many moles there are in 15.8g
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