Chapter 2:

Question 1

This type of stereoisomer is when both molecules have the same structure, but have opposing configurations of every chiral center.

a. Diasteromers.
b. Enantiomers.
c. Cis-trans isomers.
d. Constitutional isomer.

Answer 1

B - Enantiomer.

Question 2

Definition: Two molecules with the same chemical formula, but different connectivity.

Answer 2

Constitutional isomers.

Question 3

What configuration is a molecule in when it has the two highest priority groups on the same side of an alkene?

Answer 3

Z-

Question 4

What is the configuration of a molecule when it has the two highest priority groups on opposite sides of an alkene?

Answer 4

E-

Question 5

True or false: A pair of cis-trans isomers can never be diastereomers as well.

Answer 5

FALSE - Cis-trans isomers are always diastereomers.

Question 6

Two molecules appear to be non-superimposable mirror images. What can we say about this?

a. There is E and Z configurations.
b. Both have R configuration of their chiral carbons.
c. These two molecules will have opposite configurations.
d. These two molecules are virtually identical, and there will be no changes in reactivity between the two.

Answer 6

C - These two molecules will have opposite configurations - because they’re enantiomers.

Question 7

Which of the following is not a requirement for a chiral carbon?

a. 4 substients.
b. All substituents must highly reactive.
c. All substituents must be unique to each other.
d. The carbon must have no plan of symmetry.
e. The molecule will be optically active.

Answer 7

b - All substituents must be highly reactive.
e - The molecule will be optically active.

Question 8

(CH3)2CHCl :

a. Has 3 chiral carbons.
b. Is a constitutional isomer to (CH3)C2H2Cl
c. Has a plane of symmetry.
d. Will be highly reaction in a solution of NaBr.

Answer 8

C - has a plane of symmetry.

Question 9

In comformational isomers, a gauche conformation will be the most stable, as it avoids steric strain.

A - True.
B - False.
C - Could be true or false dependant on the molecule.

Answer 9

FALSE - Anti conformations (180) will be the most stable, as it will move our hgihest priority groups as far away from each other as possible.

Question 10

By what angle will a gauche conformation distance the highest priority groups?

Answer 10

120 degrees.

Question 11

Which conformation, as seen through a newman projection, will be the most reactive?

a. Staggered.
b. Eclipsed.
c. Gauche.
d. Anti.

Answer 11

Eclipsed - most unstable cause the highest priority groups overlap = most reactive.