Topic 10: Organic Compounds - Hydrocarbons

10.1What is the definition of hydrocarbon? Give several examples.
 
10.2What is the difference between an aliphatic hydrocarbon and an aromatic hydrocarbon?
 
10.3What are the three types of aliphatic hydrocarbons? [Hint: All three start with alk.]
 
10.4What are primary (1o), secondary (2o), tertiary (3o), and quaternary (4o) carbons?
 
10.5What are primary (1o), secondary (2o), and tertiary (3o) hydrogens?
 
10.6Is there such thing as a quaternary (4o) hydrogen?
 

Topic 11: Nomenclature - Alkanes

11.1What are the special names of the straight-chain alkanes up through four carbons?
 
11.2What are the systematic names of the straight-chain alkanes from 5-10 carbons?
 
11.3How do you name a branch in IUPAC nomenclature systems?
 
11.4How do you decide what the “parent hydride” is in the IUPAC substitutive nomenclature?
 
11.5How do you indicate unambiguously where a chain branch is located, especially if there are multiple branches?
 
11.6What does “iso” mean in the names isopropyl and isobutyl?
 
11.7What does sec- and tert- mean in the names sec-butyl and tert-butyl?
 
11.8What prefixes are used to indicate “one of”? “two of”? “three of”? 4-10-of?
 
11.9If there is more than one branch, how is it recommended these be numbered?
 
11.10If there is more than one branch, how is it recommended these be ordered in the name itself?
 
11.11What punctuation is used to separate numbers from letters in IUPAC names?
 
11.12What punctuation is used to separate numbers from numbers in IUPAC names?
 
11.13Are IUPAC substitutive names really all one long word, with no spaces?
 
11.14What special considerations do we need to consider for cyclic alkanes?
 

Topic 12: Alkane Conformations - Ethane and Butane

12.1What is a conformation? Are two conformations isomers of each other?
 
12.2Explain the terms staggered and eclipsed in relation to ethane conformations. How do these terms relate to common usage of these words in English?
 
12.3What is a Newman projection, and what is it good for? What are its key features?
 
12.4How is the conformational “landscape” (as illustrated in an energy diagram, for example) for rotation about the C2-C3 bond of butane different from that for ethane?
 
12.5Explain the terms gauche and anti in relation to the conformations of butane involving rotation about the C2-C3 bond. What does gauche mean in French? Why would organic chemists choose these two specific terms? How are these conformations related in terms of energy? Why?
 

Topic 13: Alkane Conformation - Cyclohexane

13.1What is the lowest-energy conformation of cyclohexane called? Describe it in detail using words, not pictures, if you can.
 
13.2What is the boat conformation, and why is it so much higher in energy than the chair conformation?
 
13.3What do the terms cis and trans mean in relation to ring systems in organic chemistry? Where have you seen them used as prefixes in standard English?
 
13.4Explain the terms equatorial, axial, and 1,3-diaxial in relation to the cyclohexane chair conformation.
 
13.5How do the ideas of gauche and anti in relation to butane also relate to cyclohexane, particularly when comparing structures with different substituents, such as 1,2-dimethylcyclohexane or 1,3-dimethylcyclohexane?
 
13.6Describe what a “ring flip” is, and how to draw one on paper. Using a plastic model, can you convert it from one chair to the other without going through the boat conformation?
 
13.7Can you draw a cyclohexane chair and its substituents such that a professional chemist can understand what you are describing?
 
13.8Given a cyclohexane derivative structure, can you predict which of the two possible chair conformations is the more favorable?
 

Topic 14: Stereochemistry - Terms

14.1What does it mean that two compounds are constitutional isomers?
 
14.2What does it mean that two compounds are configurational isomers?
 
14.3What if I told you that I think that configurational isomers are just as different from each other as constitutional isomers? Would you argue for or against this position?
 
14.4A molecule is chiral if and only if what?
 
14.5What does the prefix “a” mean in English, as in asymptomatic? Why is that relevant to this discussion?
 

Topic 15: Stereochemistry - Enantiomers and Stereogenic Centers

15.1What is an enantiomer?
 
15.2Is the following statement true or false? “A molecule is achiral if and only if it is its own enantiomer.”
 
15.3What is a stereogenic center? What are its characteristics exactly?
 
15.4How do organic chemists distinguish stereogenic centers when drawing skeletal structures?
 

Topic 16: Stereochemistry - The Cahn-Ingold-Prelog System (R and S)

16.1How is priority assigned in the “CIP” system?
 
16.2In this system, which has higher priority - #1, or #4?
 
16.3How is priority “read” on a drawing, leading to a designation of R or S?
 
16.4What is the special rule for alkenes and alkynes?
 
16.5How do these rules lead to a “sensible” assignment of priorities?
 
16.6What do you do if the #4 group is not in the back (without redrawing the structure)?
 

Topic 17: Stereochemistry - Diastereomers

17.1Do two people have to be related to be sisters (in the standard family sense)?
 
17.2What does it mean that two compounds are diastereomers (of each other)?
 
17.3Do two compounds have to be chiral to be diastereomers (of each other)?
 
17.4Does a compound have to have an enantiomer if it is a diastereomer?
 
17.5What do we call a compound that has a diastereomer but no enantiomer?
 
17.6What does conformation have to do with stereochemistry?
 

Topic 18: Stereochemistry - Optical Activity

18.1What is plane-polarized light? How is it related to circularly polarized light?
 
18.2How is plane-polarized light produced?
 
18.3What is optical activity?
 
18.4Does light travel slower or faster through a liquid than through a vacuum? Why?
 
18.5What does optical activity have to do with the speed of light and circular polarization? [Think about what might happen if a mixture of clockwise- and counter-clockwise- light is introduced to a solution that contains only one of two related enantiomers.]
 
18.6Why does a chiral compound rotate plane-polarized light? [Hint: This question requires thinking about the relationship between circularly polarized light, the speed of light NOT in a vacuum, and the relationship between plane- and circularly-polarized light.]
 
18.7What is a racemic mixture?
 
18.8How is optical rotation (“observed rotation” ?) measured?
 
18.9How is observed rotation related to specific rotation ? How is this use of the word specific here similar to its use in specific heat or specific gravity?
 
18.10Why is specific rotation more useful that observed rotation?
 

Topic 19: Stereochemistry - Mixtures of Enantiomers and Enantiomeric Excess

19.1What is enantiomeric excess (ee)? Why use the word excess here?
 
19.2What does an enantiomeric excess of 100% mean?
 
19.3What does an enantiomeric excess of 0% mean?
 
19.4How is enantiomeric excess related to specific rotation?
 
19.5How is enantiomeric excess related to the ratio of enantiomers? (For example, if the enantiomeric excess is 40%, favoring the (+) enantiomer, what is the ratio of (+) to (-) enantiomers in the mixture?)
 
69 questions
364 questions for Organic I

364 Questions for Organic I

Dearest Student. This web page is a set of questions I call Detailed Intended Learning Outcomes For Organic Chemistry (Part I). Some time ago I asked myself, "Bob, what do you think are the key questions that you hope students will be able to answer after taking Chemistry 247 at St. Olaf College?" So here you have them. Some are very simple; some require more thought. All are good questions to be thinking about as you read, discuss, and master the practical aspects of organic chemistry. They are discussion starters and review tips. There are no answers here (though there are some clues). The questions are here to help you focus on what's important (to me, at least!) and organize your learning process. The questions are grouped into topics. Bite-size chunks. Take them a few at a time. Don't feast on them all at one sitting!

(preliminary version 2021.01.15 feeback: Bob Hanson)