Question 1

Which of the following statements best explains why the boiling point of alkanes increases as the number of carbon atoms increases?

Accepted Answer

The larger surface area increases van der Waals attractions between molecules.

Question 2

What is the IUPAC name for the following structure: $$CH_3CH_2CH(CH_3$)CH_2CH_3$$?

Accepted Answer

2-methylpentane

Question 3

Which of the following is a constitutional isomer of $$C_4H_{10}$$?

Accepted Answer

isobutane

Question 4

A compound has the formula $$C_5H_{12}. $$Which of the following is NOT a possible isomer?

Accepted Answer

cyclopentane

Question 5

Which rule in IUPAC nomenclature ensures that the main chain is numbered from the end nearest a substituent?

Accepted Answer

Rule 2

Question 6

What is the correct IUPAC name for a molecule with the following structure: $$CH_3CH_2CH(CH_3$)CH_2CH_2CH_3$$?

Accepted Answer

3-methylhexane

Question 7

Which of the following best describes the difference between staggered and eclipsed conformations in ethane?

Accepted Answer

Eclipsed conformations have higher torsional energy than staggered conformations.

Question 8

Which conformation of butane is the highest in energy?

Accepted Answer

Totally eclipsed

Question 9

What is the main source of alkanes in industry?

Accepted Answer

Fractional distillation of crude petroleum

Question 10

Which of the following statements about cycloalkanes is TRUE?

Accepted Answer

Cycloalkanes contain rings of carbon atoms.

Question 11

Which type of strain is present in cyclopropane due to its bond angles?

Accepted Answer

Angle strain

Question 12

What is the most stable conformation of cyclohexane?

Accepted Answer

Chair

Question 13

Which of the following is a correct statement about 1,3-diaxial interactions in methylcyclohexane?

Accepted Answer

They occur when the methyl group is in the axial position.

Question 14

A molecule has two methyl groups on cyclohexane at positions 1 and 3. Which conformation is more stable for the trans isomer?

Accepted Answer

Both methyl groups equatorial

Question 15

Which of the following is the correct IUPAC name for a molecule with three methyl groups at positions 2, 5, and 7 on a decane chain?

Accepted Answer

2,5,7-trimethyldecane

Question 16

Which of the following is NOT a property of alkanes?

Accepted Answer

High reactivity with acids

Question 17

Which process is used to break long-chain alkanes into shorter-chain alkanes and alkenes in the petroleum industry?

Accepted Answer

Catalytic cracking

Question 18

What is the general formula for cycloalkanes?

Accepted Answer

$$C_nH_{2n}$$

Question 19

Which of the following best describes the chair-chair interconversion in cyclohexane?

Accepted Answer

Axial substituents become equatorial and vice versa.

Question 20

Which of the following is a correct statement about the stability of cycloalkanes?

Accepted Answer

Cyclohexane is most stable in the chair conformation due to lack of angle and torsional strain.

Structure and Stereochemistry of Alkanes: Study Notes

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