Question 1

Which of the following statements best explains why cyclopropane is much less stable than cyclohexane?

Accepted Answer

Cyclopropane has significant angle strain because its bond angles are $$60^\circ$$, far from the tetrahedral angle of $$109.5^\circ.$$

Question 2

Which of the following is the correct IUPAC name for the compound with the following condensed formula: $$\mathrm{(CH_3$)_3CCH_2CH_3}$$?

Accepted Answer

2,2-Dimethylbutane

Question 3

Which of the following substituents should be listed first in the IUPAC name of a molecule, according to alphabetical order?

Accepted Answer

Ethyl

Question 4

A molecule has two stereogenic centers and is found to be optically inactive. Which of the following best explains this observation?

Accepted Answer

The molecule is a meso compound.

Question 5

Which of the following best describes the difference between a staggered and an eclipsed conformation in a Newman projection of ethane?

Accepted Answer

Staggered conformations have lower torsional strain than eclipsed conformations.

Question 6

Which of the following is NOT a type of strain found in cycloalkanes?

Accepted Answer

Hydrogen bond strain

Question 7

Which of the following pairs of molecules are enantiomers?

Accepted Answer

Two molecules that are non-superimposable mirror images of each other

Question 8

Which of the following statements about chiral molecules is correct?

Accepted Answer

Chiral molecules rotate plane-polarized light.

Question 9

Which of the following is the correct R/S designation for the chiral center in 2-butanol ($$\mathrm{CH_3CH(OH)CH_2CH_3}) if $$the hydroxyl group is given the highest priority?

Accepted Answer

S

Question 10

Which of the following best describes the relationship between cis-1,2-dimethylcyclopentane and trans-1,2-dimethylcyclopentane?

Accepted Answer

They are diastereomers.

Question 11

Which of the following functional groups has the highest priority in IUPAC nomenclature?

Accepted Answer

Carboxylic acid

Question 12

A compound has the following structure: $$\mathrm{CH_3CH_2CH(CH_3$)CH_2CH_3}. $$What is the correct IUPAC name?

Accepted Answer

3-Methylpentane

Question 13

Which of the following best describes the E/Z system for alkenes?

Accepted Answer

It assigns priority to substituents on each carbon of the double bond and labels as E if the highest priority groups are on opposite sides.

Question 14

Which of the following is a constitutional isomer of $$\mathrm{C_5H_{12}}$$?

Accepted Answer

2,2-Dimethylpropane

Question 15

Which of the following best explains why the chair conformation of cyclohexane is more stable than the boat conformation?

Accepted Answer

The chair conformation minimizes both torsional and steric strain.

Question 16

Which of the following is the correct condensed formula for isobutyl chloride?

Accepted Answer

$$\mathrm{(CH_3$)_2CHCH_2Cl}$$

Question 17

Which of the following statements is true regarding optical activity?

Accepted Answer

A racemic mixture is optically inactive because the rotations of enantiomers cancel each other.

Question 18

Which of the following best describes a molecule that is achiral?

Accepted Answer

It is superimposable on its mirror image.

Question 19

Which of the following is the correct IUPAC name for a molecule with a tert-butyl group and an ethyl group attached to a pentane chain, with the tert-butyl group at carbon 3 and the ethyl group at carbon 2?

Accepted Answer

2-Ethyl-3-(tert-butyl)pentane

Question 20

Which of the following best describes the relationship between 1-bromopropane and 2-bromopropane?

Accepted Answer

They are constitutional isomers.

Alkanes and Cycloalkanes: Structure, Nomenclature, and Stereochemistry

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