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Puddle on a sunny day

  1. Jan 21, 2010 #1
    A puddle of water is on the ground on a sunny day. The energy to break hydrogen bonds between water molecules is 3.4x10-20J. To evaporate from the surface of the puddle each molecule must break two of these hydrogen bonds.

    a) Calculate the difference in internal energy between a water molecule in the liquid and vapour state at the same temperature

    b) Calculate the fraction of water molecules with sufficient energy to evaporate a 300K

    c) Suggest why the puddles temperature falls during rapid evaporation

    d) Suggest another application of cooling by evaporation

    The next parts involve the unusually large heat capacity of water

    e) the temperature is the same outside and inside a swimming pool on a warm day. You jump in and are surprised to suddenly feel cold even though the temperature still reads the same inside and outside the pool. Explain Why?

    f) State and explain two environmental consequences of waters high specific heat capacity

    I have absolutely no idea how to go about this question. Any help would be greatly appreciated.
  2. jcsd
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