Challenge Questions: are these molecules hydrophilic or hydrophobic?

Work on these questions if you’d like to test your knowledge of chemistry concepts we’ve covered and practice reading skeletal structures.

vitamin D3, Cholecalciferol

A. Noticing that Vitamin Water does not contain vitamin D3, Rufol thinks he has a business opportunity on his hands: make a vitamin beverage containing vitamin D3 for people who don’t get enough sun during the winter—or for people who just don’t get enough sun at all. Looking at the molecular structure of vitamin D3, do you think Rufol will have an easy time dissolving it into water? 

B. Taste tests show that the molecule shown is at least 30 times sweeter than sugar. Since it is also a non-caloric (zero-calorie) substance and does not raise blood sugar levels, this sweetener could be an effective sugar substitute. But will you be able to mix it into coffee or make soft drinks with it, or is it doomed to remain a pasty glob when added to beverages?

C. According to Dr. Frances Jensen, this molecule from cannibis shown seems to have promise for the treatment of certain kinds of epilepsy. Judging from its structure, do you think it could be administered as an aqueous (water-based) solution? (You can ignore the numbering of the carbon atoms.)

D. AtrazineWrite out the full structure of Atrazine from its skeletal structure, shown on the right. Is it a molecule or an ionic compound?

There are serious concerns about Atrazine contaminating drinking water. How can we tell by looking at its structure what parts of it are hydrophobic or hydrophilic, and is Atrazine overall hydrophobic or hydrophilic? Are any parts of this molecule (if it is a molecule) polar? Where would hydrogen bonds form if you tried to mix Atrazine into water? Hint: does any part of it remind you of ammonia or table salt?


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