Lecture 7: Structural Features of Alkanes

Question 1

Compounds with the same molecular formula but different connections between atoms.

Answer 1

Consitutional Isomers.

Question 2

Compounds with the same molecular formula and connections but arranged differently in space.

Answer 2

Stereoisomers

Question 3

Molecules in which the 3D arrangement of atoms results from rotation around a single sigma bond.

Answer 3

Conformational Isomers

Question 4

Conformation in which all atoms align with each other.

Answer 4

Eclipsed

Question 5

Conformation in which all atoms are out of line with each other.

Answer 5

Staggered

Question 6

Angle between the C-H bonds on the front carbon and the C-H bonds on the back carbon.

Answer 6

Dihedral Angle

Question 7

Conformation which has the highest energy.

Answer 7

Total Eclipsed Conformation.

Question 8

Conformation which has the lowest energy.

Answer 8

Anti conformation.

Question 9

Dihedral Angle of eclipsed conformation.

Answer 9

0

Question 10

Dihedral Angle of staggered conformation

Answer 10

60

Question 11

Low/intermediate energy conformation in which the CH3 groups are close but not aligned

Answer 11

Gauche

Question 12

Instability caused by adjacent C-H bonds eclipsing each other.

Answer 12

Torsional Strain

Question 13

A strain-free, non-planar conformation with bond angles of 111 degrees.

Answer 13

Chair conformation.

Question 14

H atoms lying in the same plane as the C atoms in chair conformation.

Answer 14

Equatorial

Question 15

H atoms lying above and below the plane.

Answer 15

Axial

Question 16

Atom interactions present in chair conformation which are highly unfavorable due to steric interactions.

Answer 16

1,3-diaxial interactions.

Question 17

Isomer which both methyl groups are on the same side of the ring.

Answer 17

Cis Isomer

Question 18

Isomer which both methyl groups are on opposite sides of the ring.

Answer 18

Trans Isomer

Question 19

Placing the _____ group in an equatorial position is preferred to reduce steric interference and 1,3-diaxial interactions.

Answer 19

Largest