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

One of the most frequently asked exam questions in this chapter is: “What is the relationship between the following two molecules?”. We’re going to learn a systematic method to solve these questions.  

Concept #1: Different atoms or different connectivity.

Concept #2: Same atoms, same connectivity, 0 chiral centers.

Concept #3: Same atoms, same connectivity, 1 chiral center.

Concept #4: Same atoms, same connectivity, 2 or more chiral centers.

Concept #5: Same atoms, same connectivity, 1 or more trigonal centers.

Concept #6: When to use R and S, when you don’t have to. 

Solving for R and S on every single molecule can be a headache. If the molecule hasn’t been rotated, feel free to use “different or same” as a surrogate for R and S (we’ll practice this so you see what I mean). 

Practice: Identify the relationship between the following organic compounds: 

Practice: Identify the relationship between the following organic compounds: 

Practice: Identify the relationship between the following organic compounds: 

Practice: Identify the relationship between the following organic compounds: 

Additional Problems
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Determine the relationships between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.
Determine the relationships between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Determine the relationship between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds.
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Determine the relationship between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
For each of the following pairs of compounds, determine  the relationship between the two compounds:
For each of the following pairs of compounds, determine  the relationship between the two compounds:
Determine the relationship between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Determine the relationship between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds.
Determine the relationship between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds.
For each of the following pairs of compounds, determine  the relationship between the two compounds:
For each of the following pairs of compounds, determine  the relationship between the two compounds:
For each of the following pairs of compounds, determine  the relationship between the two compounds:
Determine the relationships between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Determine the relationships between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Determine the relationships between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Determine the relationships between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Determine the relationships between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Determine the relationships between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
Determine the relationship between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
What is the relationship of the following two structures? a) Identical b) Enantiomers c) Unrelated d) Constitutional Isomers e) Diastereomers
What is the relationship between the following two compounds? A) Constitutional isomers B) Enantiomers C) Meso isomers D) Diastereomers E) Resonance structures
Determine the relationship between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds. 
What is the relationship between the following molecules? The choices are structural isomers, identical, enantiomers, diastereomers.
For each of the following pairs of molecules indicate in the box provided if they are the same molecule, enantiomers, diastereomers, conformers, or constitutional isomers. If it is a meso compound, write MESO.
What is the relationship between the members of the following pairs? That is, are they constitutional isomers, the same, or something else (specify)?
For each of the following pairs of molecules indicate in the box provided if they are the same molecule, enantiomers, diastereomers, conformers, or constitutional isomers. If it is a meso compound, write MESO.
For each of the following pairs of molecules indicate in the box provided if they are the same molecule, enantiomers, diastereomers, conformers, or constitutional isomers. If it is a meso compound, write MESO.
What is the relationship between the pairs of compounds shown below? Are they conformational isomers, stereoisomers, or not isomers?  
Which choice best describes the relationship that exists between the pair of structures below? A. Identical  B. Constitutional isomers C. Resonance structures  D. No relationship exists
For each of the following pairs of molecules identify them as one of the following: constitutional isomers (I), same molecule (S), enantiomers (E), diastereomers (D), or none of the above (N).
How are the molecules shown below related to each other? a. They are constitutional isomers b. They are identical c. They are not isomers; they are different compounds d. They are resonance structures e. They are stereoisomers
How are the molecules shown below related to each other? a. Identical b. Constitutional Isomers c. Enantiomers d. meso compounds e. diastereomers
For each pair of molecules, on the line provided state the relationship between the two structures. Possible answers could be enantiomers, consitutional isomers, or same molecule.
How are the molecules shown below related to each other? a. Identical b. Constitutional Isomers c. Enantiomers d. meso compounds e. diastereomers  
How are the molecules shown below related to each other? a. Identical b. Constitutional Isomers c. Enantiomers d. meso compounds e. diastereomers  
For each of the following pairs of molecules, indicate whether the two molecules are identical, constitutional isomers, enantiomers, or diastereomers.
What is the correct stereochemical description of the relationship between this pair of molecules? a) identical b) constitutional isomers c) enantiomers d) diastereomers
What is the correct stereochemical description for these two Fischer projections? a) identical b) meso isomers c) diastereomers d) enantiomers  
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. For each pair, choose the best one.
Indicate if the following pairs of molecules are enantiomers,  diastereomers, constitutional isomers or the same as each other.
What is the stereochemical classification of (1S,2S)-1,2-cyclohexanediol and (1R, 2S)-1,2-cyclohexanediol? a) enantiomers b) diastereomers c) meso compounds d) racemates
What is the relationship between these two structures? a) identical molecules b) conformational isomers c) constitutional isomers d) stereoisomers
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
For each of the following pairs of compounds, determine the relationship between the two compounds:
Using the following choices: enantiomers ( E), diastereomers (D), constitutional isomers (CI), conformers (C), or identical (I), identify the relationships between the molecules below.
The molecules below are: A. constitutional isomers B. enantiomers C. diastereomers D. identical  E. None of these
Identify the relationship in each of the following pairs. A) Constitutional Isomers B) Configurational Isomers C) Same molecule or Conformational Isomers  
Identify the relationship in each of the following pairs. A) Constitutional Isomers B) Configurational Isomers C) Same molecule or Conformational Isomers
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers.  
Identify the following pair as either enantiomers, diastereomers, the same, or constitutional isomers:
Consider the following pairs of structures. Designate each chirality center as (R) or (S) and identify the relationship between them by describing them as representing enantiomers, diastereomers, constitutional isomers, or two molecules of the same compound. Use handheld molecular models to check your answers. 
Determine the relationship between the following compounds as either enantiomers, diastereomers, identical, constitutional isomers or meso compounds.
For each of the following pairs of molecules, indicate whether the two molecules are identical, constitutional isomers, enantiomers, or diastereomers.
Label each stereocenter as "R" or "S" and on the line provided state whether the pair of molecules represent two enantiomers, two diastereomers, or the same compound. Draw a circle around any meso compound.
What is the correct stereochemical description of the relationship between this pair of compounds? a) identical b) constitutional isomers c) enantiomers d) diastereomers
Describe the following pairs as either enantiomers, diastereomers, the same or neither.
Describe the following pairs as either enantiomers, diastereomers, the same or neither.
Describe the following pairs as either enantiomers, diastereomers, the same or neither.
Describe the following pairs as either enantiomers, diastereomers, the same or neither.
Classify each of the following pairs as either constitutional isomers, enantiomers, diastereomers, identical, or non-isomeric.
A) Using the following choices: enantiomers ( E), diastereomers (D), constitutional isomers (CI), conformers (C), or identical (I), identify the relationship between the molecules below.  
Identify the following pair as either enantiomers, diastereomers, the same, or constitutional isomers:
Identify the following pair as either enantiomers, diastereomers, the same, or constitutional isomers:
Identify the following pair as either enantiomers, diastereomers, the same, or constitutional isomers:
Identify the following pair as either enantiomers, diastereomers, the same, or constitutional isomers:
Identify the following pair as either enantiomers, diastereomers, the same, or constitutional isomers:
Identify the following pair as either enantiomers, diastereomers, the same, or constitutional isomers:
Which of the following structures represent the same compound? Check all that apply.
Part BWhich of the following structures represent the same compound? Check all that apply.
Classify the following pair of compounds as the same compound, enantiomers, constitutional isomers, or not isomeric.a. same compoundb. enantiomersc. constitutional isomersd. not isomeric  
What is the relationship between the following molecules?a. No relationshipb. Diastereomersc. Enantiomersd. Constitutional Isomerse. Identical 
Which of the following pairs of molecules are considered stereoisomers?
Tell whether the following two compounds are constitutional isomers, identical, stereoisomers, or are unrelated. 2,3,3-trimethylpentane cis-1,3-dibromocyclobutane 
What is the relationship of the following two structures?