Which of the following structures represent the same compound? Which ones represent different compounds?

(c)

Which of the following structures represent the same compound? Which ones represent different compounds?

(e)

Which of the following structures represent the same compound? Which ones represent different compounds?

(f)

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.

Draw the structure that corresponds with each name.

a. 3-ethyloctane

b. 4-isopropyldecane

Draw the structure that corresponds with each name.

c. sec-butylcycloheptane

d. 2,3-dimethyl-4-propylnonane

Draw the structure that corresponds with each name.

e. 2,2,4,4-tetramethylhexane

f. trans-1,3-diethylcyclopentane

Draw the structure that corresponds with each name.

i. tert-butylcyclohexane

j. pentylcyclohexane

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

a. an isopropylheptane

b. a diethyldecane

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

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

e. a (2,3-dimethylpentyl)cycloalkane

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

f. a bicyclononane

Give the IUPAC names of the following alkanes.

(a) CH₃C(CH₃)₂CH(CH₂CH₃)CH₂CH₂CH(CH₃)₂

(b)

Construct a graph, similar to Figure 3-11, of the torsional energy of 3-methylpentane along the C2―C3 bond.

a. Place C2 in front, represented by three bonds coming together in a Y shape, and C3 in back, represented by a circle with three bonds pointing out from it.

b. Define the dihedral angle as the angle between the methyl group on the front carbon and the ethyl group on the back carbon.

Construct a graph, similar to Figure 3-11, of the torsional energy of 3-methylpentane along the C2―C3 bond.

c. Begin your graph at the 0° dihedral angle and begin to turn the front carbon.

Construct a graph, similar to Figure 3-11, of the torsional energy of 3-methylpentane along the C2―C3 bond.

e. Indicate which conformations are the most stable (lowest energy) and the least stable (highest energy).

The following names are all incorrect or incomplete, but they represent real structures. Draw each structure and name it correctly.

a. 2-ethylpentane

b. 3-isopropylhexane

The following names are all incorrect or incomplete, but they represent real structures. Draw each structure and name it correctly.

c. 5-chloro-4-methylhexane

d. 2-dimethylbutane

The following names are all incorrect or incomplete, but they represent real structures. Draw each structure and name it correctly.

e. 2-cyclohexylbutane

f. 2,3-diethylcyclopentane

In each pair of compounds, which compound has the higher boiling point? Explain your reasoning.

a. octane or 2,2,3-trimethylpentane

In each pair of compounds, which compound has the higher boiling point? Explain your reasoning.

b. nonane or 2-methylheptane

In each pair of compounds, which compound has the higher boiling point? Explain your reasoning.

c. 2,2,5-trimethylhexane or nonane

There are eight different five-carbon alkyl groups.

a. Draw them.

b. Give them systematic names.

There are eight different five-carbon alkyl groups.

c. In each case, label the degree of substitution (primary, secondary, or tertiary) of the head carbon atom bonded to the main chain.

Use a Newman projection about the indicated bond to draw the most stable conformer for each compound.

a. 3-methylpentane about the C2―C3 bond

Use a Newman projection about the indicated bond to draw the most stable conformer for each compound.

b. 3,3-dimethylhexane about the C3―C4 bond

a. Draw the two chair conformations of cis-1,3-dimethylcyclohexane, and label all the positions as axial or equatorial.

b. Label the higher-energy conformation and the lower-energy conformation.

c. The energy difference in these two conformations has been measured to be about 23 kJ (5.4 kcal) per mole. How much of this energy difference is due to the torsional energy of gauche relationships?

d. How much energy is due to the additional steric strain of the 1,3-diaxial interaction?

Draw the two chair conformations of each compound, and label the substituents as axial and equatorial. In each case, determine which conformation is more stable.

a. cis-1-ethyl-2-isopropylcyclohexane

b. trans-1-ethyl-2-isopropylcyclohexane

Draw the two chair conformations of each compound, and label the substituents as axial and equatorial. In each case, determine which conformation is more stable.

c. cis-1-ethyl-3-methylcyclohexane

d. trans-1-ethyl-3-methylcyclohexane

Draw the two chair conformations of each compound, and label the substituents as axial and equatorial. In each case, determine which conformation is more stable.

e. cis-1-ethyl-4-methylcyclohexane

f. trans-1-ethyl-4-methylcyclohexane