Isomers

Question 1

What is a constitutional isomer?

Answer 1

Structural isomer

Question 2

Structural isomer

Answer 2

Same chemical formula and different connectivity

Question 3

Physical property

Answer 3

Characteristics that do not change the composition of a molecule

Question 4

Chemical Property

Answer 4

Related to the reactivity of the molecule which results from changes in the chemical composition

Question 5

What usually dictates chemical properties?

Answer 5

Functional groups

Question 6

What are the two types of stereoisomers?

Answer 6

Conformational and Configurational

Question 7

Stereoisomers

Answer 7

Same formula and connectivity, different spatial arrangement of atoms

Question 8

Conformational isomers

Answer 8

Differ in rotation around single bonds

Question 9

How are configurational isomers interconverted?

Answer 9

Interconverted by breaking bonds

Question 10

How do you separate a racemic mixture?

Answer 10

Add only one enantiomer of another compound to create two diasteromers (++ and +-) or (– and +-)

Question 11

Most energetically favorable conformational isomer

Answer 11

Anti

Question 12

Least energetically favorable conformational isomer

Answer 12

Totally eclipsed

Question 13

Two types of staggered conformations

Answer 13

Anti and Gauche

Question 14

Axial position

Answer 14

Perpendicular to plane of ring

Question 15

Equatorial position

Answer 15

Parallel to plane of ring

Question 16

What position to bulky groups take in cyclic conformations?

Answer 16

Equatorial

Question 17

What are the two types of configurational isomers?

Answer 17

Enantiomers and Diastereomers

Question 18

Enantiomers

Answer 18

Nonsuperimposable mirror images

Question 19

Nonsuperimposable mirror images

Answer 19

Enantiomers

Question 20

Are diastereomers mirror images?

Answer 20

No

Question 21

Chiral

Answer 21

Mirror image cannot be superimposed on original object

Question 22

Optical activity

Answer 22

Rotation of plane-polarized light by a chiral molecule

Question 23

Molecule that rotates light clockwise

Answer 23

Dextrorotatory

Question 24

Dextrorotatory designation

Answer 24

d- or +

Question 25

d- designation

Answer 25

Rotates light clockwise

Question 26

+ designation

Answer 26

Rotates light clockwise

Question 27

Molecule that rotates light counter clockwise

Answer 27

Levorotatory

Question 28

Levorotatory designation

Answer 28

l- or -

Question 29

l- designation

Answer 29

rotates light counterclockwise

Question 30

- designation

Answer 30

rotates light counterclockwise

Question 31

Racemic mixture

Answer 31

Equal + and - | No optical activity

Question 32

Does a racemic mixture have optical activity

Answer 32

No

Question 33

Calculation of specific rotation

Answer 33

Specific rotation = observed rotation/(concentration times length of tube)

Question 34

Most stable cyclohexane configuration

Answer 34

Chair

Question 35

Diastereomers

Answer 35

Contain two or more chiral centers and differ at some but not all of these centers

Question 36

How many stereoisomers does a compound with n chiral centers have?

Answer 36

2^n

Question 37

What are geometric isomers?

Answer 37

Cis/trans isomers

Question 38

Meso compound

Answer 38

Has multiple chiral centers but also contains a plane of symmetry and does not rotate light

Question 39

Is a meso compound optically active?

Answer 39

No

Question 40

Relative conformation

Answer 40

Configuration in relation to another chiral molecule

Question 41

Absolute conformation

Answer 41

Exact spatial arrangement of atoms/groups

Question 42

Z conformation

Answer 42

Two highest priority groups around a double bond are on the same side of the bond

Question 43

E conformation

Answer 43

Two highest priority groups around a double bond are on opposite sides of the bond

Question 44

Which direction do wedge bonds project?

Answer 44

Out of the plane of the page

Question 45

Which direction do dashed bonds project?

Answer 45

Into the plane of the page

Question 46

In a fischer projection which direction do vertical lines project?

Answer 46

Into the plane of the page

Question 47

In a fischer projection which direction do horizontal lines project?

Answer 47

Out of the plane of the page

Question 48

R conformation

Answer 48

Clockwise 1-3 around a chiral center

Question 49

S conformation

Answer 49

Counterclockwise 1-3 around a chiral center

Question 50

When you skip #4 to assign R/S, will the designation be the same or opposite?

Answer 50

Opposite

Question 51

When you make 1 switch to assign R/S, will the designation be the same or opposite?

Answer 51

Opposite

Question 52

When you move #4 to the back, how do you further manipulate the Fischer projection and will the designation be the same or opposite?

Answer 52

Switch the other two groups and then it will be the same

Question 53

What are the length units in calculation of specific rotation?

Answer 53

decimeters (10dm in 1m)

Question 54

What is the concentration unit in calculation of specific rotation?

Answer 54

g/mL