Which of the following structures does not have constitutional isomers?

Choose five that represent compounds of formula C₆H₁₅N from the following drawings.

Which of the structures shown below are constitutional isomers of an alkane with a molecular formula of C₉H₂₀?

Give the relationship of the given pairs of molecules as the same compounds, constitutional isomers, or not isomers.

a. CH₃—CH=CH—CH₃ and CH₃—CH₂—CH=CH₂
b. CH₃—CH₂—CH₃ and CH₃—CH=CH₂
c. CH₂=CH—CH₂—CH₂—CH₂—CH₃ and CH₃—CH₂—CH=CH—CH₂—CH₃

Show all constitutional isomers with a molecular formula of C₉H₂₀ and have four methyl substituents. Use line-angle drawings.

Determine the number of constitutional isomers that can be generated from C₃H₈O.