CHEM 2020 Lecture Notes - Lecture 4: Newman Projection, Rotational Energy, Post-Office Box

• School: York University
• Department: Chemistry
• Course: CHEM 2020
• Professor: Ayyaz Mallick

Document Summary

Jan 20 chem 2020: there are 3 class, summary : symmetry in ethane. Six fold inversion symmetry: the conformations of ethane differ in energy due to steric & torsional strain. Eclipsed forms are energy maxima (least stable) (12. 6 kj/mol) Staggered forms are energy minima (most stable: the relative instability of eclipsed forms is from two kinds of strain. Propane (maxima : 13. 8kj/mol: the rotational energy of propane is a little bit latger than in ethane. Unlike in ethane, the eclipsed forms of propane involve a ch3 group, which is sterically more demanding than h. Butane the rotational; energy profile for butane is more complex. As before, there are spin axed that make both halves the same. There are also minor plane that render the two h in _ The most unstable form is totally eclipsed. The other eclipsed form is also energy maxima.