Ch. 5 - ChiralitySee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

Molecules with the same chemical formula can be connected differently. We call these similar molecules isomers, and there are different types. 

What is the relationship between these two compounds?

Concept #1: Determining when molecules are different. 

If you are confused by how to solve for IHD, refer to my Index of Hydrogen Deficiency topic. 

What is the relationship between these two compounds?

Concept #2: Determining when molecules are constitutional isomers. 

*These are also known as structural isomers

What is the relationship between these two compounds?

Concept #3: Determining when molecules are stereoisomers.

Heads up: The terms enantiomers, diastereomers, and meso compounds are all used to describe specific types of stereoisomers—we’ll get to those later in this chapter.  

What is the relationship between these two compounds?

Concept #4: Determining when molecules are conformers.

Since conformers are simply rotations along single bonds, these would also count as identical molecules; they can easily twist back into position with each other.  

Additional Problems
Select the compounds in each group that are isomers and specify whether they are constitutional isomers or stereoisomers. 
Select the compounds in each group that are isomers and specify whether they are constitutional isomers or stereoisomers. 
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
For each pair of compounds below, determine whether they are identical compounds, constitutional isomers, stereoisomers, or different conformations of the same compound:
Determine whether the two structures in each of the following pairs represent constitutional isomers, different conformations of the same compound, or stereoisomers that cannot be interconverted by rotation about single bonds. 
Determine whether the two structures in each of the following pairs represent constitutional isomers, different conformations of the same compound, or stereoisomers that cannot be interconverted by rotation about single bonds. 
Determine whether the two structures in each of the following pairs represent constitutional isomers, different conformations of the same compound, or stereoisomers that cannot be interconverted by rotation about single bonds.  (d) cis-1,2-Dimethylcyclopentane and trans-1,3-dimethylcyclopentane 
Determine whether the two structures in each of the following pairs represent constitutional isomers, different conformations of the same compound, or stereoisomers that cannot be interconverted by rotation about single bonds. 
Select the compounds in each group that are isomers and specify whether they are constitutional isomers or stereoisomers. 
Select the compounds in each group that are isomers and specify whether they are constitutional isomers or stereoisomers. 
Select the compounds in each group that are isomers and specify whether they are constitutional isomers or stereoisomers. 
For each of the pairs shown below, give the best answer which describes the relationship between each molecule in the pair. Choose from one of the four following: (a) constitutional isomers; (b) different conformations of the same compound; (c) stereoisomers that cannot be interconverted by rotation about single bonds; or (d) the same conformation of the same compound. In part a through part d of this problem, a letter may be used more than once, or it may not be used at all.
For each of the pairs shown below, give the best answer which describes the relationship between each molecule in the pair. Choose from one of the following: (i) constitutional isomers; (ii) different conformations of the same compound; or (iii) stereoisomers that cannot be interconverted by rotation about single bonds. (For each pair, choose the best one; give one letter. ) In part a through part d of this problem, a letter may be used more than once.
For each of the pairs shown below, give the best answer which describes the relationship between each molecule in the pair. Choose from one of the following: (i) constitutional isomers; (ii) different conformations of the same compound; or (iii) stereoisomers that cannot be interconverted by rotation about single bonds. (For each pair, choose the best one; give one letter.) In part a through part d of this problem, a letter may be used more than once.