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View Diary: BP Catastrophe Liveblog Mothership: 44 - organic chemistry 101 Edition (105 comments)

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  •  What were you trying to say here? (2+ / 0-)
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    Wee Mama, peraspera

    Water boils at 100°C. Octane boils at 125°C but it is about eight times as heavy! It is that network of hydrogen bonds that holds water together so well.

    Are you trying to say that water is eight times as heavy as octane?  That octane is eight times as heavy as water?  Neither is accurate, of course.  

    The specific gravity of pure water is 1, sea water is about 1.02 and octane is 0.918.

    •  The molecular weight of octane is about eight (9+ / 0-)

      times as big as that of water. Molecular size and charge are two major factors in what temperature something boils at. Since octane is eight times more massive than water if it were similar chemically you would expect it to have a much higher boiling point (you can see this effect in the link to boiling points for simple hydrocarbons). The fact that water has a similar boiling point is due to the extensive hydrogen bond network.

      Water is unusual in lots of ways - how much heat it can absorb, its surface tension, the fact that ice floats - and all of them can be explained by the hydrogen bond network.

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