Module 5: Stereochemistry

Question 1

these are different compounds with the same molecular formula

Answer 1

isomers

Question 2

these are isomers having atoms bonded to different atoms

Answer 2

constitutional isomers

Question 3

isomers with a difference in 3-D arrangement only

Answer 3

stereoisomers

Question 3

Differ in the way atoms are oriented in space (3D arrangement of atoms)

Answer 3

stereoisomers

Question 4

it is composed of chains that wind into a helix

Answer 4

starch polymer

Question 5

all parts of the object align with its mirror image

Answer 5

superimposable

Question 5

this consists of an extensive three-dimensional network held together by hydrogen bonds

Answer 5

cellulose

Question 5

identical through the looking glass

Answer 5

mirror image

Question 6

nonsuperimposable on its mirror image

Answer 6

chiral

Question 7

superimposable on its mirror image

Answer 7

achiral

Question 8

chiral or achiral: the bonds and atoms align

Answer 8

achiral

Question 9

these usually contain a plane of symmetry

Answer 9

achiral molecules

Question 10

these are stereoisomers that are nonsuperimposable on their mirror images.

Answer 10

enantiomers

Question 11

A carbon atom bonded to four different groups is called?

Answer 11

tetrahedral stereogenic center, asymmetric center, or chirality center

Question 12

these are not stereogenic centers

Answer 12

CH2 and CH3 groups (sp and sp2 hybridized)

Question 13

Any molecule with ___________________________________ is a chiral compound and exists as a pair of enantiomers.

Answer 13

one tetrahedral stereogenic center

Question 14

Before ____________________ was used by pregnant women to alleviate their morning sickness.

Answer 14

thalidomide

Question 14

represents an asymmetric carbon as the point of intersection of two perpendicular lines; horizontal lines represent the bonds that project out of the plane of the paper toward the viewer, and vertical lines represent the bonds that extend back from the plane of the paper away from the viewer

Answer 14

fisher projection

Question 15

The atom of __________________________ gets the highest priority

Answer 15

highest atomic number

Question 16

Two enantiomers have _________________ physical properties

Answer 16

identical

Question 16

Because two enantiomers have identical physical properties, they cannot be separated by common physical techniques like?

Answer 16

distillation

Question 17

Two enantiomers have identical physical properties (e.g. melting point, boiling point, solubility) except for how they interact with?

Answer 17

plane polarized light

Question 17

A compound that does rotate the plane of polarization is said to be?

Answer 17

optically active

Question 18

Clockwise rotation:

Answer 18

dextrorotatory d or (+)

Question 18

A compound that does not rotate the plane of polarization is said to be?

Answer 18

optically inactive

Question 19

Counterclockwise rotation:

Answer 19

levorotatory l or (-)

Question 20

Equimolar mixture of enantiomers will be optically inactive – this are called?

Answer 20

racemic mixture (racemate)

Question 21

this is obtained from grapes, so it was also called racemic acid (racemus is Latin for “a bunch of grapes”).

Answer 21

tartaric acid

Question 22

these are non-mirror image stereoisomers (has two stereogenic centers)

Answer 22

diastereomers

Question 23

these have the same R,S designations at every tetrahedral stereogenic center

Answer 23

identical compounds

Question 23

these can be used to determine whether two compounds are identical, enantiomers, or diastereomers

Answer 23

R,S configurations

Question 23

these have exactly opposite R,S designations

Answer 23

enantiomers

Question 24

these have the same R,S designation for at least one stereogenic center and the opposite for at least one of the other stereogenic ecenters

Answer 24

diastereomers

Question 24

these are mirror images

Answer 24

enantiomers

Question 24

these are not mirror images

Answer 24

diastereomers