Isomers

Question 1

Three classes

Answer 1

Constitutional, conformational, stereoisomers

Question 2

Constitutional isomers

Answer 2

Structural isomers that differ in the positions of their constituent atoms

Question 3

Conformational isomers

Answer 3

Isomers that arise from different orientations around a sigma bond, which may rotate relative to one another

Question 4

Conformational isomers

Answer 4

Either eclipsed or staggered

Eclipsed > staggered, in terms of energy

Question 5

Conformational isomers

Answer 5

The relative populations of conformational isomers are temperature dependent

Question 6

Cyclo- conformational isomers

Stability

Answer 6

Chair>twist>boat

Question 7

Stereoisomers

Answer 7

Differ in their spatial, 3-D arrangements

Question 8

Geometrical isomers

Answer 8

When rotation about a bond or bonds is not possible due to a ring system of pi bond

Question 9

Enantiomers

Answer 9

Nonsuperimposable, chiral mirror images

Question 10

Diastereomers

Answer 10

Stereoisomers that are not Mirror images of each other

Geometrical isomers are diastereomers

Question 11

Enantiomers

Answer 11

Have identical physical and chemical properties; they are not easy to separate

Question 12

Diastereomers

Answer 12

Have different physical and chemical properties; they are easy to separate by conventional means

Question 13

Racemic mixture

Answer 13

50-50 mixture of a pair of enantiomers

Question 14

R and S convention

Answer 14

R equals right, S equals left

Question 15

R and S convention naming steps

Answer 15

1. ) assign priorities based on mass
2. ) visualize with lowest priority pointing away from you
3. ) rotate going 1,2,3

Question 16

Meso molecules

Answer 16

Have chiral centers but are not chiral overall

Mirror image is identical in every way, have internal mirror plane

Question 17

Optical activity meso

Answer 17

Optically inactive

Question 18

Optical activity racemic

Answer 18

Optically inactive

Question 19

Optical activity enantiomers

Answer 19

Optically active but flip in opposite direction

Question 20

Optical rotation

Answer 20

Plane polarized light is a group of photons that are all moving in the same direction AND have electromagnetic fields oscillating in the same place

Question 21

Optical activity chiral centers

Answer 21

Optically active and rotate plane polarized light