All the structures shown here have the molecular formula C₈H₁₈. Which structures are the same molecule? (Hint: One way to answer this question is to determine the chemical name for each structure.)

Verified step by step guidance

Identify each structure: Begin by examining each structure provided. Look for the arrangement of carbon atoms and any branching that occurs.

Name each structure: Use IUPAC naming rules to determine the name of each structure. Start by identifying the longest carbon chain, then number the chain to give the substituents the lowest possible numbers.

Compare the names: Once you have the IUPAC names for each structure, compare them. Structures with the same name are the same molecule.

Check for isomers: Remember that isomers have the same molecular formula but different structures. Ensure that the structures are not just different representations of the same molecule.

Verify: Double-check your work by ensuring that each structure's name corresponds correctly to its arrangement of atoms.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Isomerism

Isomerism refers to the phenomenon where two or more compounds have the same molecular formula but different structural arrangements or spatial orientations of atoms. In the case of C8H18, there are several isomers, including straight-chain and branched forms, which can exhibit different physical and chemical properties despite having the same molecular formula.

Structural Formula

The structural formula of a compound provides a visual representation of the arrangement of atoms within the molecule. It indicates how atoms are bonded together and can help identify isomers by showing different connectivity or branching patterns. Understanding structural formulas is essential for determining whether two compounds are identical or different.

Nomenclature

Nomenclature is the system of naming chemical compounds based on their structure and composition. The International Union of Pure and Applied Chemistry (IUPAC) provides rules for naming organic compounds, which can help distinguish between isomers. By applying these naming conventions, one can identify whether different structures represent the same molecule or different isomers.