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Matching Two Hydrogen-Bond Contact Sites 4 questions
Matching Two Hydrogen-Bond Contact Sites
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A model of a removable molecular coating has two N–H groups on one connector. Their H atoms are 0.60 nm apart. A facing surface has two oxygen atoms that can accept hydrogen bonds. In this alignment model, one H can face one O. Both H atoms can face both O atoms at once when the O–O spacing differs from the H–H spacing by no more than 0.05 nm.
| Surface | Spacing between the two oxygen sites (nm) |
|---|---|
| P | 0.62 |
| Q | 0.90 |
Question 1
Which surface can make two hydrogen-bond contacts at once in the stated alignment model?
- P only
- Q only
- Both surfaces
- Neither surface
Question 2
Explain why the two surfaces give different predictions even though each has two oxygen acceptor sites.
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The exhibit adds a surface R with its two O sites exactly 0.60 nm apart. Its display can show the two N–H groups as a row facing the row of oxygen sites.
Question 3
Draw the two N–H groups and the two O sites. Use dotted lines to show both allowed hydrogen-bond contacts in surface R. Keep the N–H bonds solid.
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Question 4
A modified connector has the same outline, but one of its two N–H groups is replaced by a group that cannot donate a hydrogen bond. Evaluate the claim that it can still make both contacts with R.
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