CHM136H1 Lecture Notes - Lecture 10: Van Der Waals Strain, Newman Projection, Ethane

• School: UTSG
• Department: Chemistry
• Course: CHM136H1

Document Summary

Staggered: where atoms on one c are as far apart as possible from atoms on adjacent carbon. Regardless of looking at front of back, the chlorines are perfectly 180 away from each other. Not in line, furthest away from adjacent bonds. Eclipsed: where atoms on one c are as close as possible to atoms on adjacent carbon. Bonds are essentially in line with each other, all aligned in one position. Force that opposes rotation of one part of molecule about a bond while other part is held fixed. Ie, one group is fixed, while the other group rotates bout the bond. When a molecule goes from staggered to eclipsed, repulsion builds up between the bonds. This strain resists the movement of the molecule to an eclipsed state. In ethane, the torsional strain between the conformations is about 12 kj / mol. Ie per mole of ethane, that much energy is needed to change the conformation from staggered to eclipsed.