AAMC Scored C/P #22

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FoodisGood163

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Maybe I'm just overthinking this, but aren't covalent bonds supposed to be intramolecular bonds? I struck through B and C because my though process was that covalent bonds are not intermolecular interactions and hydrogen bonds are not intramolecular interactions. Picked D because it was a covalent interaction, which at the time I was under the impression that they were intramolecular interactions. Can someone clear this up for me, please?

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I don't remember the specifics of the question, but whether you view covalent bonds as intra- or inter-molecular depends on vantage point. Usually, you take two molecules and covalently bond them to each other, resulting in one larger molecule. So the covalent bond was formed between two molecules but now exists within one larger molecule that is the sum of the two smaller ones.

Also, H-bonds can be either intra- or inter-molecular. For intra-molecular, think of a beta-hydroxyketone. For inter-molecular, think of water.
 
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Without actually seeing the two compounds in question, it's not possible to answer your question.

Hydrogen bonding in its pure chemistry sense is the polar positive attraction between the hydrogen atom in one molecule to the polar negative attraction in another molecule(potentially a different functional group on the same molecule depending on geometries). In order for hydrogen bonding to occur, H- must be bonded directly to N, O, or Fl. Due to polar covalent nature of the bonds, the resulting uneven sharing results in a partial charge. This partial charge is what the hydrogen bond derives it's strength from. So you end up with a whole bunch of partial positive and partial negative charges that tend to arrange themselves into their lowest E configuration possible. That's why ethanol has a much higher BP than a molecule such as butane, even though butane has the heavier MW.

Also, from a person with a very heavy background in chemistry, this question is terrible! An "intermolecular" covalent bond suggest a formal bond, and therefore the two molecules are now joined as one single molecule...making the bond an intramolecular covalent bond. Any formal bond between two atoms, molecules, pieces of string cheese make it a single entity. I can tell that a chemist didn't write this question.

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