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Arranging the boiling point

  1. Dec 4, 2012 #1
    arrange the boiling point of the following compounds
    methoxymethane,butane,pentane and water
    I quickly arrange like this
    butane<pentane<methoxymethane<water
    but after checking wiki,it should be
    methoxymethane<butane<pentane<water
    In my knowledge,methoxymethane is a polar molecule,so i should have a higher boiling point
    Why,that it's not make sense?
    Also which of the following has the higher priority when we are considering the boiling point, the polarization or the molecular size?
    thanks!
     
  2. jcsd
  3. Dec 4, 2012 #2
    The ether is only slightly polar, so the hydrophobic interactions of the longer alkenes are stronger.
     
  4. Dec 5, 2012 #3
    in general ethers can be regarded as basically nonpolar and have boiling points comparable to alkanes of similar molecular mass.

    indeed have you noticed that the dipole-dipole interaction is extremely weak and doesn't really matter (in terms of phase change temperatures) in many cases, with only hydrogen bonding significantly altering the boiling point?

    Carbon monoxide is isoelectronic with nitrogen N2, has the same mass, is much more polar than N2 yet they boil at almost the same temperature: 82 K vs. 78 K.

    However, the dielectric properties of polar molecules are going to be different.
     
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