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

Verified step by step guidance

1. Examine each structure to identify the carbon skeleton and the position of the double bond. This will help determine if they are the same compound or different.
2. Structure 1 and Structure 3 both have a double bond between the first and second carbon atoms in a straight chain, indicating they are the same compound.
3. Structure 2 and Structure 5 have a double bond between the second and third carbon atoms, but the chain is branched differently, indicating they are different compounds.
4. Structure 4 has a double bond between the second and third carbon atoms in a straight chain, which is different from Structure 1 and Structure 3.
5. Structure 6 has a double bond between the first and second carbon atoms, similar to Structure 1 and Structure 3, indicating they are the same compound.

Key Concepts

Structural Isomerism

Structural isomerism occurs when compounds have the same molecular formula but different structural arrangements of atoms. This concept is crucial for identifying whether the given structures represent the same or different compounds, as variations in connectivity can lead to distinct chemical properties and identities.

Cis-Trans Isomerism

Cis-trans isomerism, a type of stereoisomerism, arises in compounds with restricted rotation around a double bond or a ring structure. It is essential for understanding the differences between structures 1 and 2, as the spatial arrangement of substituents can affect the compound's physical and chemical properties, despite having the same connectivity.

Alkene Nomenclature

Alkene nomenclature involves naming compounds based on the longest carbon chain containing the double bond and the position of the double bond. This concept helps in identifying and comparing the structures, as the position and configuration of the double bond are key factors in determining whether the structures are identical or different.