Final answer:
Hexane and cyclohexane are structural isomers with the same molecular formula, C6H12, but different atom arrangements. Hexane has a straight chain, whereas cyclohexane is a ring. The diverse structures illustrate the concept of isomerism in chemistry.
Step-by-step explanation:
Hexane and cyclohexane are considered isomers, but they are not functional isomers; they are types of isomers called structural isomers. This means they have the same molecular formula, which is C6H12, but they have different structures and arrangements of atoms. Hexane is a straight-chain alkane with six carbon atoms linked in a linear fashion, while cyclohexane has its six carbon atoms connected in a ring structure.
According to the IUPAC System of Nomenclature, the diversity of possible isomers increases with the number of carbon atoms in the hydrocarbon. For example, there are several isomers for hexanes, each with a unique structure, such as n-hexane, 2-methylpentane, etc. Cycloalkanes, like cyclohexane, introduce a new dimension to isomerism because their carbons are connected in a ring, which is confirmed by the observation that the molecule is puckered into a chair or boat conformation rather than being planar.
Mixing hexane and cyclohexane in their pure liquid states does not result in a solution driven by a decrease in enthalpy (∆Hsoln), but rather an increase in entropy, due to the mixing of molecules and the resulting increase in disorder.