chapter 3 conformations

Question 1

The reactivity and properties of a compound depend to some extent on the

Answer 1

shape of its molecules

Question 2

conformation

Answer 2

The shape of a molecule with respect to bond rotations and other “easy” processes is called i

Question 3

Ethane (H3CCH3) an infinite number of concentrations related by
rotation about the

Answer 3

C–C bond

Question 4

most important conformations of ethane are the

Answer 4

staggered and eclipsed

Question 5

• Staggered conformation:

Answer 5

each
C–H bond bisects an H–C–H
angle

Question 6

• Eclipsed conformation:

Answer 6

each C–H bond is aligned with an
adjacent C–H bond

Question 7

Conformations of ethane can be shown in the

Answer 7

wedge-and-dash form,
sawhorse
and newman projection

Question 8

Elipsed angles

Answer 8

0 degrees

Question 9

gauche angles

Answer 9

60 degrees

Question 10

Anti angle

Answer 10

180 degrees

Question 11

Torsion angles are also called

Answer 11

dihedral angle

Question 12

Eclipsed vs staggard, which is more stable? Which is least stable

Answer 12

Eclipsed conformers are least stable; staggered conformers are most stable.

Question 13

eclipsed conformations are shown at the

Answer 13

peak of the Potential energy diagram

Question 14

vast majority of molecules are in

Answer 14

staggered conformation at any given time

Question 15

The rotation process is

Answer 15

extremely rapid (t1/2

Question 16

Increased energy of eclipsed conformer due to two
factors

Answer 16

-Destabilization of eclipsed conformer due to nonbonding (steric) interactions

-Stabilization of staggered conformer due to hyperconjugative
sC–H → s*
C–H interactions