I need help for number two and all the parts that go with it thank you !

Condensed structural formula:
[tex]\begin{gathered} Propene:CH_2=CHCH_3 \\ 2-butene:CH_3CH=CHCH_3 \\ 1-butene:CH_2=CHCH_2CH_3 \end{gathered}[/tex]Condensed Structural formula:
Propene: CH2=CHCH3
2-butene: CH3CH=CHCH3
1-butene: CH2=CHCH2CH3