Question 1

Which of the following best describes an asymmetric carbon (also called a chiral carbon)?

Accepted Answer

A carbon atom bonded to four different atoms or groups.

Question 2

Optical isomers are molecules that:

Accepted Answer

Have the same molecular formula but different three-dimensional structures that cannot be superimposed.

Question 3

Consider the following molecule: $$\mathrm{CH_3CH(OH)CH_2CH_3} (2-$$butanol). Which carbon is asymmetric?

Accepted Answer

The second carbon (CH(OH))

Question 4

Why can't optical isomers of a molecule be superimposed onto each other?

Accepted Answer

Because their atoms are arranged in a way that their three-dimensional structures are mirror images but not identical.

Question 5

Which of the following statements about glucose and galactose is TRUE?

Accepted Answer

They are stereoisomers that differ in the arrangement around one asymmetric carbon.

Question 6

Given the Fischer projection of D-glucose, how many asymmetric carbons does it possess?

Accepted Answer

Four

Question 7

Which of the following best explains why your left and right hands are considered optical isomers?

Accepted Answer

They are mirror images that cannot be superimposed onto each other.

Question 8

If a molecule contains two asymmetric carbons, how many possible stereoisomers can it have?

Accepted Answer

$$4$$

Question 9

Which of the following molecules would NOT have an asymmetric carbon?

Accepted Answer

$$\mathrm{CH_3CH_2CH_3} ($$propane)

Question 10

Which of the following is a correct definition of a diastereomer?

Accepted Answer

Isomers that are not mirror images and differ at one or more asymmetric carbons.

Question 11

A student builds a model of a molecule with the formula $$\mathrm{C_3H_7OH}$$ and finds that the central carbon is bonded to an OH group, a methyl group, an ethyl group, and a hydrogen. Is this carbon asymmetric?

Accepted Answer

Yes, because it is bonded to four different groups.

Question 12

Which of the following best describes the difference between geometric and optical isomers?

Accepted Answer

Geometric isomers differ in the spatial arrangement around a double bond, while optical isomers differ in the arrangement around an asymmetric carbon.

Question 13

If a molecule has the formula $$\mathrm{C_4H_{10}O}$$ and contains an asymmetric carbon, which of the following is a possible name for the molecule?

Accepted Answer

2-butanol

Question 14

Which of the following statements about the ring forms of glucose is correct?

Accepted Answer

The alpha and beta forms differ in the arrangement of the OH group on the first carbon.

Question 15

A molecule has the following structure: $$\mathrm{CH_3CH(OH)CH_2CH_2OH}. $$How many asymmetric carbons does it contain?

Accepted Answer

One

Question 16

Which of the following is a real-world consequence of the existence of optical isomers in biological molecules?

Accepted Answer

Only one isomer may be biologically active, while the other is inactive or harmful.

Question 17

Which of the following best explains why the presence of an asymmetric carbon does not guarantee a molecule will be optically active?

Accepted Answer

The molecule may have a plane of symmetry that cancels optical activity.

Question 18

Which of the following is a correct application of the concept of stereoisomerism in pharmaceuticals?

Accepted Answer

One stereoisomer may be therapeutic, while the other may be inactive or cause side effects.

Asymmetric Carbons and Isomers: Lab 4 Part 3 of 3

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