[ChelOcean]

Hey! Can someone help me out?  My book doesn't do a very swell job explaining these questions and "google" wasn't helping either (I think I'm just really unsure of what sites are legit  ).

1. Why do fish-hook arrows show the movement of electrons?  Why is this a significant notation?

2. What is the repeating structural unit in poly[methyl methacrylate]?

3. What purpose does the addition of 20% sodium hydroxide serve in the synthesis of Nylon 6-6?

4. What purpose does the addition of a few drops of water serve in the synthesis polyurethane foam? 

Thanks love,
chels

All of these questions come from Synthetic Polymers

[nj_bartel]

1. Why do fish-hook arrows show the movement of electrons?  Why is this a significant notation?

I'm not sure what you're asking in the first part.  You can't actually show the movement of electrons without violating the Uncertainty Principle, but it provides a useful guideline that allows the mechanism to be understandable.



2. What is the repeating structural unit in poly[methyl methacrylate]?

 http://en.wikipedia.org/wiki/Plexiglas



3. What purpose does the addition of 20% sodium hydroxide serve in the synthesis of Nylon 6-6?

How would OH- ions react with the reactant(s) that form Nylon 6-6?