First I want to state this is not something you should see on the DAT, and I have noted you have already taken the DAT.
Manifesto, this is Dr. Romano's revised answer. Dr. Romano holds a Phd in Organic Chemistry and just loves it...I don't share his passion for Orgo.
If a single group is present.....and we flip the ring..we have a conformer. If 2 groups are present.....things get complicated,,,,,,I have seen professors get this wrong. Ok..If the 2 groups are different,,,say methyl and ethyl.....1,2.....1,3 or 1,4,,,,,,cis and trans molecules give CONFORMATIONAL DIASTEREOMERS upon the flip. Now,,,,,if the groups are the same,,,,, a Cis 1,2 gives a CONFORMATIONAL ENANTIOMER ,,,,,,Trans 1, 3 gives an Identical compound,,,,,,, and Cis 1,4 gives an Identical Compound as well......all the rest give Conformational Diastereomers . I hope this helps.....Excellent Question !!!!
Dr. Jim Romano