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Flashcards in Chapter 5 Deck (30)
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1

Define isomers

Different compounds with the same molecular formula

2

What are the two different types of isomers?

Constitutional and stereoisomers

3

Characteristics of constitutional isomers

- different IUPAC names

- different physical and chemical properties

4

Characteristics of stereoisomers

same exact molecule just different spatial arrangement of their atoms

*different from stereochemistry

5

Define configuration

3D arrangement

6

Define superimposable

to align all parts of a molecule with its mirror image

ex: right and left socks are the same shape or each other

7

Define achiral

a molecule that is superimposable

8

Define chiral

a molecule that is non-superimposable

9

What are the two types of stereoisomers?

Enantiomers and diastereomers

10

Define enantiomers

A chiral stereoisomer which mirror image is not superimposable

11

Define diastereomers

Stereoisomers that are not an enantiomer or a mirror image. May or may not be chiral

12

Define a tetrahedral stereogenic center

A carbon atom bonded to four different groups

13

Are cis and trans an enantiomer or a diastereomer?

ALWAYS a diastereomer

14

When will a molecule be achiral?

when there is no stereogenic center

15

If a molecule only has one stereogenic center, what is it always?

Chiral, nonsuperimposable enantiomer

16

If a molecule has two or more stereogenic centers, is it chiral or achiral?

It depends

17

Chiral centers have what type of hybridization?

Sp3

18

What are the purpose of R and S

To differentiate between enantiomer pairs

19

What is the first step in labeling R and S pairs?

Label the atom with the highest atomic number as 1 and work down atomic numbers

20

What is rule #2 when labeling R or S

If there are two of the same atoms on the stereogenic center, the one that has branches w higher atomic numbers is higher in priority

21

What makes a R configuration?

-H is in the back and 1-2-3-4 is clockwise

- H is in the front and 1-2-3-4 is counterclockwise

22

What makes a S configuration?

- If H is in the back, and 1-2-3-4 is counterclockwise

- H is in front and 1-2-3-4 is clockwise

23

How do you determine the max # of stereoisomers?

2^# of chiral centers

24

Define mesocompound

A molecule with chiral centers but is achiral bc of mirror plane (perfect symmetry)

25

What is important about mesocompounds?

The only have R vs. S groups... no r v. r or s v. s

26

What is alpha in optical activity of chiral molecules?

Alpha is the angle of difference of light going into sample and light coming out

27

Define dextrorotatory

Rotation to the right (+)

28

Define levorotatory

Rotation to the left (-)

29

What is the same about the rotation of a R and S enantiomer?

the magnitude of alpha is the same

30

Define racemic mixtures

An equal amount of two enantiomers