Topic 1: General - Drawing Organic Structures

1.1What is the difference between a condensed structure and a skeletal structure?
 
1.2What is the difference between a Lewis structure and a skeletal structure?
 
1.3Why do organic chemists essentially never draw proper Lewis structures?
 
1.4Why do organic chemists often not show carbon or hydrogen atoms on skeletal structures?
 
1.5What are the rules relating to showing and hiding hydrogen atoms on skeletal structures?
 
1.6How do you figure out where the lone pairs are on a skeletal structure?
 

Topic 2: General - Resonance Contributors

2.1What are three key features of resonance contributors?
 
2.2Which sigma hybridization (sp, sp2, sp3) is never involved in resonance? Which is most common? Why?
 
2.3Why do we say resonance contributor? -- And not something like resonance “compound”?
 
2.4What is the difference between a set of resonance contributors and a set of isomers?
 
2.5Why do we refer to resonance contributors as being more or less representative rather than comparing them using “more stable” or “less stable”?
 
2.6Given two resonance contributors, what are three characteristics that can help us predict which is the most representative?
 
2.7Without using curved arrows, draw multiple resonance contributors for a compound or ion of your choice. Given one structure, what are the basic methods you can use to identify another contributor? “All” resonance contributors? (Can we even ref+H16er to “all” in the context of resonance contributors?)
 

Topic 3: General - Electronegativity and Electron Density

3.1What does electronegativity measure?
 
3.2What is the fundamental physical principle behind the idea of electronegativity?
 
3.3How does electronegativity trend across a row of the periodic table, from left to right?
 
3.4How does electronegativity trend going down a column of the table?
 
3.5How can these trends be rationalized? (Careful! Going down a column is the tricky one!)
 
3.6What is meant by the term electron density?
 
3.7How is electronegativity related to electron density?
 
3.8Why are organic chemists so interested in electronegativity and electron density?
 

Topic 4: General - Bronsted-Lowry Acids and Bases

4.1What is the definition of a Bronsted-Lowry base? A Bronsted-Lowry acid?
 
4.2How can a compound be both a Bronsted-Lowry acid and a Bronsted-Lowry base? Example?
 
4.3What is the traditionally defined difference between a strong acid and a weak acid?
 
4.4What are the names and formulas of the six strong inorganic acids?
 
4.5On a horizontal line with -10 on the left and 50 on the right, place each of the structures of the following compounds or ions (collectively referred to as “species” in organic chemistry) at its proper location based on its pKa value:
a.acetic acid, water, ethanol
b.water, ammonia, methane
c. ethyne (acetylene), ethene (ethylene), methane
d.anilinium, ammonium, ammonia
e.phenol, ethanol
Explain the trends in pKa for the five series above in terms of structure, emphasizing resonance and inductive effects. Use terms such as electrons, nuclei, protons, electron density, hybridization, s-character, and electronegativity. Do not use anthropomorphic words such as likes, or wants.
 
4.6Why is it incorrect (or at the very least, misleading) to refer to benzoic acid as a “strong organic acid”?
 

Topic 5: General - Predicting the Outcome of Acid-Base Reactions

5.1How can we use pKa values to predict the favored direction of an acid-base reaction, given structures of both reactants and products?
 
5.2If you don‘t know the exact pKa of the compounds involved, how could you still make an educated guess as to the favored direction of an acid/base reaction?
 
5.3Given just two reactants, how can we predict the products of an acid-base reaction (figure out which is the acid and which is the base, then what the two products are)?
 
5.4Given a structure of an organic compound with multiple hydrogen atoms, how do we predict which hydrogen is the most acidic?
 
5.5Given the structure of an organic compound with multiple heteroatoms, how do we predict which heteroatom is most basic?
 

Topic 6: General - The Relationship between pKa and pH

6.1What is the difference between pH and pKa?
 
6.2What is so special about the situation when the pH of an aqueous solution matches the pKa of an acid in that solution?
 
6.3How can we use understanding of pKa, solubility, and pH for the practical purpose of separating organic compounds after a complex reaction?
 
6.4Both ethyl ether and dichloromethane are common organic solvents used in extraction. Why, from a purely practical point of view, might you choose one over the other?
 
6.5What makes a separatory funnel so unique? How do you use a separatory funnel?
 

Topic 7: General - Lewis Acids

7.1What is the definition of Lewis acid and Lewis base ?
 
7.2What column of the periodic table is particularly well known for elements that form compounds that are Lewis acids? (Why is that, in terms of hybridization?)
 
7.3Give three examples of Lewis acids involving elements in this column that are Lewis acids but not Bronsted-Lowry acids. What is it about their structures that makes them Lewis acids?
 

Topic 8: Organic Compounds - Functional Groups

8.1What is a functional group?
 
8.2What are the three functional groups that we find in hydrocarbons? What descriptive names are given to compounds with each of these functional groups?
 
8.3What are the two functional groups that are formed by adding single-bonded oxygen atoms to a hydrocarbon structure? What descriptive names are given to compounds with each of these functional groups?
 
8.4What functional group is formed by adding one double-bonded oxygen atom to a hydrocarbon structure? What two descriptive names are given to compounds with each of these functional groups?
 
8.5What is the descriptive name of a compound that has a single-bonded nitrogen atom with attached hydrocarbon chains or rings?
 
8.6How can a compound be both an ether and an alcohol? Give an example.
 
8.7Why can a compound NOT be both a hydrocarbon and an alcohol?
 

Topic 9: Organic Compounds - Physical Properties and Reactivity

9.1Explain each of the following terms, describe the principles behind them, and rank them in order of increasing strength: Van der Waals forces, dipole-dipole interactions, hydrogen bonding, ionic bonding.
 
9.2What is polarizability? And what is its relevance to organic chemistry?
 
9.3Explain trends in boiling point relative to:
(a)number of carbon atoms in hydrocarbons
(b)branching in hydrocarbons
(c)addition of all-carbon bonded heteroatoms to a hydrocarbon structure
(d)addition of heteroatoms that are also bonded to hydrogen

 
9.4How is solubility in water related to the structure of organic compounds and ions?
 
9.5How is solubility in ethyl ether related to the structure of organic compounds and ions?
 
9.6Rank the following list of solvents from “nonpolar” to “very polar”: acetone, ethanol, ethyl ether, hexane, water. Why such a difference?
 
9.7What does it mean for a reactive site to be nucleophilic? Give three examples.
 
9.8What does it mean for a reactive site to be electrophilic? Give two examples.
 
55 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)