quiz 4 key - orgo

quiz 4 key - orgo - 4 18.4 kJ/mole H to CH 3 eclipsing 6 CH...

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Chem 221 Quiz 4 KEY 1. Draw three constitutional isomers with the formula C 6 H 14 2. Draw two stereoisomer s with the formula C 6 H 12 . There are many possibilities for this…here are a couple…. 3. Consider the molecule 2,3-dimethylbutane. a) Sighting along the C2-C3 axis, draw the Newman Projection representing the most stable conformation of the molecule. CH 3 H 3 C H CH 3 CH 3 H b) Sighting along this same axis, draw the Newman Projection for the least stable conformer. H H 3 C CH 3 CH 3 CH 3 H c) How much more stable (in kJ/mol) is the conformer in a) than the conformer in b)? Use the info below to help (you may or may not need to use all of these numbers) and put your answer in the box. Interaction Energy cost in kJ/mol H to H eclipsing
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Unformatted text preview: 4 18.4 kJ/mole H to CH 3 eclipsing 6 CH 3 to CH 3 eclipsing 11 CH 3 CH 3 Gauche 3.8 All other interactions can be approximated as costing zero kJ/mole answer CH 3 H 3 C H CH 3 CH 3 H H H 3 C CH 3 CH 3 CH 3 H Energy cost = 11 kJ/mole + 11 kJ/mol + 4 kJ/mol = 26.0 kJ/mol Energy cost = 3.8 kJ/mole + 3.8 kJ/mol = 7.6 kJ/mol difference of 1 8 . 4 k J / m o l e 4. Draw BOTH chair conformations for the following molecule. Then CIRCLE the most stable conformation. (Please draw your picture carefully. Credit can not be given to ambiguous pictures.) H H CH 3 H CH 3 CH 3 H CH 3 H more stable (2 out of 3 methyls are equatorial) H 3 C CH 3 H...
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This note was uploaded on 04/29/2008 for the course CHEM 221 taught by Professor Fillinger during the Spring '08 term at Ithaca College.

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quiz 4 key - orgo - 4 18.4 kJ/mole H to CH 3 eclipsing 6 CH...

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