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-   -   Easy question about Boiling Point (https://www.askmehelpdesk.com/showthread.php?t=530904)

  • Dec 2, 2010, 06:45 AM
    pop000
    Easy question about Boiling Point
    Why NeopentaneC(CH3)4 Have Low boiling point then Pentane C5H12? Because the surface area ?

    Thanks
  • Dec 2, 2010, 07:53 AM
    DrBob1
    Just like the butanes, neopentane has a lower boiling point than it's straight chain isomer n-pentane. And for the same reason. Of course the boiing point of the third isomer, isopentane, is right in the middle. But have you noted their BOILING POINTS? Completely reversed!!
  • Dec 2, 2010, 07:55 AM
    DrBob1
    Comment on DrBob1's post
    I mean their melting points
  • Dec 2, 2010, 08:23 AM
    pop000
    Comment on DrBob1's post
    Yes Pentane Melting point – 129.8 °C, Neopentane Melting point −16.6 °C , Butane Melting point −138.4 °C





  • Dec 2, 2010, 08:45 AM
    pop000
    Not both Neopentane and Pentane have a straight chain ?
  • Dec 2, 2010, 10:28 AM
    Unknown008

    Pentane has a longer straight chain and Neopentane has a shorter one, which is also branched, hence why there is a lower surface area of contact between the latter molecules.

    Quote:

    yes Pentane Melting point – 129.8 °C, Neopentane Melting point −16.6 °C , Butane Melting point −138.4 °C
    Are you sure those are correct? I thought that pentane is a liquid at room temperature... I guess you mean boiling points.
  • Dec 2, 2010, 11:40 AM
    pop000
    Comment on Unknown008's post
    Oh OK thanks .
  • Dec 2, 2010, 04:49 PM
    DrBob1
    n-Pentane has a MELTING POINT of -129.5 oC, this would seem usual for a typical hydrocarbon, Neopentane melts at -16.6 oC; very high for a hydrocarbon of such a low molecular weight. It thus has a liquid range of about 25 Co.
  • Dec 3, 2010, 01:33 AM
    pop000
    Comment on DrBob1's post
    Thanks for your answer

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