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Homework Help: Heat of Mixing & differential enthalpy of dilution

  1. Jun 19, 2006 #1
    I want to know what's difference between heat of mixing and differential heat of dilution. I am working on calcium chloride solution. I need to know also from where i can get heat of mixing of calcium chloride solution.
    Thanking you
  2. jcsd
  3. Jun 19, 2006 #2

    The heat of solution you can get it from Perry's Chemical Handbook or Elementary Principles of Chemical Process.
  4. Jun 19, 2006 #3


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    Typically, you get what are called Integral tables for heat of dilution. Such a table (as the one linked above) lists enthalpy changes (relative to infinite dilution, where h = 0) as a function of molality. So the heat of dilution to go from molality M1 to molality M2 is simply the difference between two values in the table, namely h(M1) - h(M2) and it would have units of say, kJ.

    If you plot the heat of dilution vs molality (you will see that it is often a monotonically increasing curve up to pretty high concentrations), the slope of that curve at any chosen molality is the differential heat of dilution at that molality. From an integral table, it is (approximately) = {h(M+dM) - h(M-dM)}/2dM (with units of kJ/molal)
    Last edited: Jun 19, 2006
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