CHEM 112 Lecture Notes - Lecture 7: Staggered Conformation, Ethane, Substituent

• School: Queen's University
• Department: Chemistry
• Course: CHEM 112
• Professor: Richard Oleschuk

Document Summary

Lecture 7: saturated hydrocarbons, only single bonds, normal formula if cnh2n+2, free rotation around the c-c bonds, have confirmations, molecules change between conformations by single bond rotations. Different confirmations are the same molecule, same properties. Confirmations are not isomers: ethane molecule described by conformations (staggered conformation is shown here, confirmations affect chemical reactivity. Eclipsed is higher energy because when the hydrogens repel each other when they are overlapping so they will spin to go to lower energy, but the power of the repulsion is the cause of the higher potential energy. At room temperature this is what causes the bonds to spin. Bulkier things get the more potential energy because they want to get out of that position. Total eclipsed- methyl groups are overlapping, most energy. Gauche- no overlap but methyl"s aren"t directly opposite so still a little bulky. Anti- methyl"s completely apart, no overlapping, lowest energy.