Question 1

Which of the following compounds is classified as an alkane?

Accepted Answer

$$\mathrm{CH_3CH_2CH_3}$$

Question 2

What is the general formula for an acyclic (open-chain) alkane?

Accepted Answer

$$\mathrm{C_nH_{2n+2}}$$

Question 3

Which of the following statements best explains why the boiling point of alkanes increases with increasing molecular weight?

Accepted Answer

Larger alkanes have greater surface area, leading to stronger van der Waals forces.

Question 4

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

$$\mathrm{CH_3CH_2CH(CH_3$)CH_2CH_3}$$

Accepted Answer

3-methylpentane

Question 5

A student is asked to name the following structure:

$$\mathrm{CH_3CH_2CH(CH_3$)CH_2CH_2CH_3}$$

Which of the following is the correct IUPAC name?

Accepted Answer

3-methylhexane

Question 6

Which of the following is a correct statement about the chair conformation of cyclohexane?

Accepted Answer

The chair conformation has no eclipsing interactions and bond angles of $$109.5^\circ.$$

Question 7

Which of the following best describes a gauche interaction in butane?

Accepted Answer

A staggered conformation where the dihedral angle between the two methyl groups is $$60^\circ.$$

Question 8

Which of the following is the most stable conformation of butane?

Accepted Answer

Staggered anti conformation ($$180^\circ$$ between methyl groups)

Question 9

A compound is named 2,3-dimethylpentane. Which of the following is its correct structure?

Accepted Answer

A five-carbon chain with methyl groups on carbons 2 and 3.

Question 10

Which of the following statements about cycloalkanes is correct?

Accepted Answer

Cycloalkanes contain rings of carbon atoms and have the general formula $$\mathrm{C_nH_{2n}}.$$

Question 11

Which of the following is the correct IUPAC name for a six-carbon ring with a single ethyl group attached?

Accepted Answer

ethylcyclohexane

Question 12

Which of the following is true regarding the stability of cis-1,3-dimethylcyclohexane conformers?

Accepted Answer

The diequatorial conformation is more stable than the diaxial conformation.

Question 13

Which of the following best describes a spirocyclic compound?

Accepted Answer

A compound in which two rings share a single carbon atom.

Question 14

A student is asked to draw the Newman projection of ethane looking down the C1–C2 bond. Which of the following is true about the most stable conformation?

Accepted Answer

The most stable conformation is staggered, with a dihedral angle of $$60^\circ$$ between hydrogens.

Question 15

Which of the following is the correct IUPAC name for the compound with the following structure?

A seven-carbon chain with methyl groups at carbons 2, 4, and 6.

Accepted Answer

2,4,6-trimethylheptane

Question 16

Which of the following is a correct statement about the nomenclature of alkyl substituents?

Accepted Answer

The prefix 'iso-' is considered when alphabetizing substituents, but 'sec-' and 'tert-' are not.

Question 17

Which of the following best explains why cyclohexane adopts a chair conformation?

Accepted Answer

To minimize both angle strain and torsional strain, resulting in bond angles of $$109.5^\circ$$ and staggered hydrogens.

Question 18

Which of the following is the correct IUPAC name for a compound with a five-carbon ring and two methyl groups on adjacent carbons?

Accepted Answer

1,2-dimethylcyclopentane

Question 19

Which of the following statements about the melting points of alkanes is correct?

Accepted Answer

Alkanes with an even number of carbons have higher melting points than those with an odd number.

Structure and Stereochemistry of Alkanes: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard