4. Alkanes and Cycloalkanes

Which of the following best describes the structure of $1,4-\mathrm{dimethylcyclohexane}$?

Which of the following compounds is a $\mathrm{cycloalkene}$?

Which of the following correctly names a $\mathrm{cyclohexane}$ ring with $\mathrm{methyl}$ groups at carbons $1$, $3$, and $5$, assuming the lowest possible set of locants is used?

Draw the structure and give the molecular formula for each of the following compounds.

a. 1-ethyl-3-methylcycloheptane

b. isobutylcyclohexane

What is the correct IUPAC name for a cyclohexane ring with a methyl group at carbon $1$ and an ethyl group at carbon $3$?

Which of the following molecular formulas corresponds to a cycloalkane?

Each of the following descriptions applies to more than one alkane. In each case, draw and name two structures that match the description.

c. a cis-diethylcyclohexane

d. a trans-dihalocyclopentane

Draw and name the six isomeric cyclopentanes of molecular formula C₇H₁₄. These will include four constitutional isomers, of which two show geometric (cis-trans) stereoisomerism.

Draw and name the five cycloalkane structures of formula C₅H₁₀. Can any of these structures give rise to geometric (cis-trans) isomerism? If so, show the cis and trans stereoisomers.

trans-1,2-Dimethylcyclobutane is more stable than cis-1,2-dimethylcyclobutane, but cis-1,3-dimethylcyclobutane is more stable than trans-1,3-dimethylcyclobutane. Use drawings to explain these observations.

Name the following cycloalkanes using the IUPAC system of nomenclature. [Hint: Each molecule exemplifies one of the cycloalkane nomenclature rules in Table 3.10.]

(a) rule 1

Name the following cycloalkanes using the IUPAC system of nomenclature. [Hint: Each molecule exemplifies one of the cycloalkane nomenclature rules in Table 3.10.]

(c) rule 2

Name the following cycloalkanes using the IUPAC system of nomenclature. [Hint: Each molecule exemplifies one of the cycloalkane nomenclature rules in Table 3.10.]

(e) rule 3

Name the following cycloalkanes using the IUPAC system of nomenclature. [Hint: Each molecule exemplifies one of the cycloalkane nomenclature rules in Table 3.10.]

(g) rule 4

Give IUPAC names for the following compounds.