Final answer:
To classify two disubstituted cyclohexane molecules, it's crucial to analyze their spatial configurations. They could be enantiomers, diastereomers, constitutional isomers, or the same compound, based on whether they are mirror images, have different three-dimensional orientations, or just different representations of the same molecular structure due to bond rotations.
Step-by-step explanation:
When evaluating two disubstituted cyclohexane molecules, one must consider the spatial arrangement of the substituents to classify the relationship between the molecules. If the molecules are non-superimposable mirror images of each other, they are enantiomers. If the molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in space, without being mirror images, they are diastereomers. In cases where the same molecule can be drawn in different ways due to rotations around single bonds, such as 1,2-dichloroethane, they represent the same compound rather than isomers. When isomers have different connections of atoms, they are constitutional isomers. Lastly, molecules that are neither isomers nor related structurally are classified as not isomeric.
A molecule with more than one stereocenter can demonstrate various isomeric relationships. The trans and cis forms of a molecule such as 1,2-dimethylcyclopropane are examples of diastereomers because they differ in the configuration at one or more stereocenters. Furthermore, 1,2-dichloroethane shows that the ability of single bonds to rotate can lead to multiple representations of the same molecule. Understanding these concepts ensures the accurate classification of the two disubstituted cyclohexane molecules in question.