Question 1

Which of the following best describes the functional group present in alkenes?

Accepted Answer

Double bond

Question 2

What is the correct IUPAC name for the following structure: $$\mathrm{CH_3CH_2CH(CH_3$)CH_2CH_2CH_3}$$?

Accepted Answer

3-methylhexane

Question 3

Which of the following is the correct name for a nine-carbon alkane with an ethyl group at carbon 3 and a methyl group at carbon 6?

Accepted Answer

3-ethyl-6-methylnonane

Question 4

Which of the following statements about the naming of cycloalkanes with two substituents is correct?

Accepted Answer

The first substituent alphabetically is assigned carbon 1.

Question 5

What is the main source of torsional strain in the eclipsed conformation of ethane?

Accepted Answer

Repulsion between electron clouds in C-H bonds

Question 6

Which conformation of butane is the lowest in energy?

Accepted Answer

Anti (staggered)

Question 7

A molecule of propane in its eclipsed conformation has a total strain energy of $$3.3\ \mathrm{kcal/mol}. If $$each H/H eclipsing interaction is $$1.0\ \mathrm{kcal/mol}$$, what is the energy of the H/CH$$_3$$ eclipsing interaction?

Accepted Answer

$$1.3\ \mathrm{kcal/mol}$$

Question 8

Which of the following best describes the difference between a primary and a tertiary carbon?

Accepted Answer

A primary carbon is bonded to one other carbon; a tertiary carbon is bonded to three.

Question 9

Which of the following is the correct IUPAC name for the structure shown below?

$$\mathrm{CH_3CH_2CH_2CH_2C(CH_3$)_3CH_2CH_2CH_2CH_3}$$

Accepted Answer

5-tert-butyldecane

Question 10

Which of the following best describes the difference between cis and trans isomers in cycloalkanes?

Accepted Answer

Cis isomers have substituents on the same face; trans isomers have them on opposite faces.

Question 11

Which of the following is a correct statement about the combustion of alkanes?

Accepted Answer

Combustion of alkanes produces only water and carbon dioxide.

Question 12

Which of the following interactions contributes most to the strain energy in the totally eclipsed conformation of butane?

Accepted Answer

C-CH$$_3/C-CH$_3$$ eclipsing interactions

Question 13

Which of the following best explains why cyclopropane has significant torsional strain?

Accepted Answer

It has six eclipsing C-H bonds and cannot twist to relieve strain.

Question 14

Which of the following is the correct order of increasing ring strain per CH$$_2$$ group for cycloalkanes (from least to most)?

Accepted Answer

Cyclohexane \u003c Cyclopentane \u003c Cyclobutane \u003c Cyclopropane

Question 15

Which of the following best describes the energy difference between axial and equatorial conformations of methylcyclohexane?

Accepted Answer

The equatorial conformation is more stable by $$7.6\ \mathrm{kJ/mol}.$$

Question 16

Which of the following is the correct Newman projection for the lowest energy conformation of butane?

Accepted Answer

The two methyl groups are anti to each other (180° apart).

Question 17

Which of the following best describes the effect of a ring flip in cyclohexane?

Accepted Answer

Axial and equatorial positions are interchanged.

Question 18

Which of the following is the correct IUPAC name for a cycloundecane with a bromo group at carbon 3, a chloro group at carbon 1, and an ethyl group at carbon 7?

Accepted Answer

3-bromo-1-chloro-7-ethylcycloundecane

Structure and Stereochemistry of Alkanes: Nomenclature, Conformations, and Cycloalkanes

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