Question 1

Which of the following objects is most likely to be chiral in the context of everyday items?

Accepted Answer

A pair of scissors

Question 2

What is the best method to quickly determine if a molecule is chiral?

Accepted Answer

Look for a mirror plane

Question 3

Which of the following statements about enantiomers is correct?

Accepted Answer

Enantiomers are mirror images that are not superimposable

Question 4

A molecule has a carbon atom bonded to four different groups: $$\mathrm{Br}$$, $$\mathrm{Cl}$$, $$\mathrm{F}$$, and $$\mathrm{H}. $$What is this carbon atom called?

Accepted Answer

A chiral center

Question 5

Which of the following is NOT a requirement for a carbon atom to be a chiral center?

Accepted Answer

It must have a mirror plane

Question 6

Which of the following atoms can be a chiral center, according to the study materials?

Accepted Answer

Any atom bonded to four different groups

Question 7

What is the first step in the Cahn-Ingold-Prelog (CIP) convention for assigning (R) and (S) configuration?

Accepted Answer

Assign priorities based on atomic number

Question 8

If two substituents attached to a chiral center have the same atomic number, what should you do according to the CIP rules?

Accepted Answer

Move outward to the next atoms attached to those substituents

Question 9

A molecule has the following groups attached to a chiral center: $$\mathrm{OH}$$, $$\mathrm{NH_2$}$$, $$\mathrm{CH_3$}$$, and $$\mathrm{H}. $$According to the CIP rules, which group gets the highest priority?

Accepted Answer

$$\mathrm{OH}$$

Question 10

After assigning priorities and placing the lowest priority group in the back, you observe the sequence 1-2-3 is clockwise. What is the configuration?

Accepted Answer

(R)

Question 11

If the lowest priority group is not in the back, what should you do after assigning priorities and determining the direction?

Accepted Answer

Flip the configuration letter (R to S or S to R)

Question 12

Which of the following best describes a stereocenter?

Accepted Answer

Any atom where flipping it gives a new stereoisomer

Question 13

Which of the following molecules is most likely to be achiral?

Accepted Answer

A molecule with a mirror plane

Question 14

Which of the following is a real-world example of a chiral biological molecule?

Accepted Answer

DNA

Question 15

A student is analyzing a molecule and finds it is superimposable on its mirror image. What can be concluded?

Accepted Answer

The molecule is achiral

Question 16

Which of the following best explains why amino acids (except glycine) are chiral?

Accepted Answer

They have a carbon atom bonded to four different groups

Question 17

A molecule has two chiral centers. How many possible stereoisomers can it have?

Accepted Answer

$$2^2 = 4$

Question 18

Which of the following statements about the (R) and (S) nomenclature is correct?

Accepted Answer

It describes the 3D arrangement of groups around a chiral center

Question 19

In a medical context, why is chirality important for drug molecules?

Accepted Answer

Different enantiomers can have different biological effects

Question 20

A molecule has the following groups attached to a chiral center: $$\mathrm{Br}$$, $$\mathrm{Cl}$$, $$\mathrm{F}$$, and $$\mathrm{H}. If $$the lowest priority group ($$\mathrm{H}) is $$not in the back, and the sequence 1-2-3 is counterclockwise, what is the configuration?

Accepted Answer

Flip the letter: (R)

Chap 5 part 1 Stereochemistry: Chirality, Chiral Centers, and (R)/(S) Nomenclature

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