Advices For Studying Organic Chemistry

conformations is 12 kJ mol−^1 (2.87 kcal mol−^1 ).

Figure 4.7 Potential energy changes that accompany rotation of groups about the
carbon-carbon bond of ethane.
2) Unless the temperature is extremely low (−250 °C), many ethane molecules (at
any given moment) will have enough energy to surmount this barrier.
3) An ethane molecule will spend most of its time in the lowest energy, staggered
conformation, or in a conformation very close to being staggered. Many times
every second, it will acquire enough energy through collisions with other
molecules to surmount the torsional barrier and will rotate through an eclipsed
conformation.
4) In terms of a large number of ethane molecules, most of the molecules (at any
given moment) will be in staggered or nearly staggered conformations.

6. Substituted ethanes, GCH 2 CH 2 G (G is a group or atom other than hydrogen):
   
   
   1. The barriers to rotation are far too small to allow isolation of the different
      staggered conformations or conformers, even at temperatures considerably
      below rt.