The "dome" is caused by the surface tension of the compound as well as the "wetting" power of the liquid against the glass test tube. The "dome" really is an upside down dome, is it not. That is the meniscus for water. The surface tension (which you can read about in your text or notes) is different for different molecules. Here are some good picture of a meniscus.
http://www.google.com/images?q=picture+liquid+meniscus&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&source=univ&sa=X&ei=gkqJTZTdIdLpgQevja3ZDQ&ved=0CDEQsAQ&biw=787&bih=398
In an experiment we did in class ethanol was poured into a test tube and we noticed that the ethanol did not collect and form a dome at the opening of the tube in the same way that water had. I know why water collected at the opening, but i'm not sure why the ethanol didn't collect as much. Our teacher was going on about the amount of bonds between ethanol molecules but i couldn't really catch what he was trying to say. could anyone help clear this up for me? Thanks!
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