Chapter 2

Question 1

Conformational isomers

Answer 1

Differ in rotation around a single bond

Question 2

What are the types of conformational isomers

Answer 2

Staggered, anti staggered, gauche, eclipsed, total eclipsed

Question 3

Staggered conformation

Answer 3

groups 60 degrees apart

Question 4

Anti-staggered conformation

Answer 4

two large groups are 180 degrees apart

Question 5

gauche conformation

Answer 5

two large groups are 60 degrees apart

Question 6

eclipsed

Answer 6

two large groups are in front of each other

total eclipsed is directly in front of each other

Question 7

Angle strain

Answer 7

created by stretching or compressing angles from normal size

Question 8

torsional strain

Answer 8

from eclipsing conformations

Question 9

non bonded strain

Answer 9

interactions between substituents on non adjacent carbons

**sterics

Question 10

Axial vs equatorial

Answer 10

axial is up or down from plane

equatorial is in plane (STABLE)

Question 11

Configurational enantiomers

Answer 11

can only be interchanged by breaking and reforming bonds

Question 12

enantiomers

Answer 12

non superimposable mirror images. Opposite stereochemistry at every chiral carbon

Same chemical and physical properties, rotate plane polarized light differently

Question 13

Optical activity

Answer 13

ability to rotate plane polarized light

D= positive, rotate to right

L= negative, rotate to left

Question 14

Racemic mix

Answer 14

equal concentration of two enantiomers. Not optically active, they cancel each other out

Question 15

meso compounds

Answer 15

have an internal plane of symmetry. Are optically inactive (two side cancel each other out)

have chiral centers

Question 16

Diastereomers

Answer 16

non mirror image stereoisomers

Differ at some but not all chiral centers

Different chemical and physical properties

Question 17

Cis/trans isomers

Answer 17

diastereomers that have different position at immovable bond (double bond)

Question 18

Chiral center

Answer 18

4 different groups attached to central carbon

Question 19

relative configuration

Answer 19

gives stereochemistry in relation to another molecule

Question 20

absolute configuration

Answer 20

gives stereochemistry

uses Cahn Ingold priority rules

Question 21

Cahn Ingold rules

Answer 21

higher atomic number has higher priority.

Question 22

Z vs. E alkene

Answer 22

Highest priority on same side=Z

Question 23

R vs S configuration

Answer 23

Lowest priority in back, draw circle

Clockwise=R
Counterclockwise=S

Question 24

Fischer diagram

Answer 24

vertical lines go into page, dash

horizontal lines come out, wedge

Switching or rotating 90 will invert stereochemistry