Study Goals and Aids
Overall Course Goals
In addition to the specific and more detailed goals listed for each topic we study, we have overall goals, things that we want to take away with us from the course. The individual study topics and goals are simply a means to the more general end. We want to:
- Understand the connection between molecular structure and chemical reactivity;
- Learn to think more clearly and logically;
- Improve our problem solving skills, learning methodology that works with many kinds of problems;
- Learn to communicate scientific information clearly and accurately, with both words and pictures.
- Review structural ideas from general chemistry, including:
- the Octet Rule and Lewis structures;
- formal charges;
- predicting molecular shape from Lewis structures (VSEPR)
- Ionic vs covalent bonding
- polar bonds and polar molecules;
- resonance and delocalization of electrons;
- Structure of atomic orbitals
- Hybridization of atomic orbitals
Interaction of atomic orbitals to form molecular orbitals
When you have finished these reviews, you should be able to:
- Quickly and accurately draw Lewis structures
- Identify polar molecules and polar bonds within molecules
Identify the hybridization of atoms in a molecular structure and describe the approximate geometry of those atoms
- Use VSEPR to describe the three-dimensional arrangement of ligands about an atom
- Describe how atomic orbitals are combined into molecular orbitals
This chapter introduces new notations for writing the structures of organic molecules, and interpreting thosse structures. It establishes the key idea for analyzing the chemical reactions of organic molecules: the functional group. Finally, two ways of classifying those reactions are introduced.
When you have finished this chapter you should
- Be able to identify the common functional groups in organic molecules
- Classify organic reactions according to
- Overall transformation: addition, elimination, substitution, or rearrangement
- Nature of the reagent: electrophilic or nucleophilic
- Be able to read/write structures for organic molelcules in both condensed and line notation
- Be able to use the dash-wedge notation to show the shape of organic molecules
- Use the "curly arrow" formalism to draw resonance structures
Review ideas from general chemistry about acid/base theory.
When you have finished this chapter, you should:
- Bronsted acid-base chemistry;
- Review the pK notation for expressing acidity and basicity
- Lewis acid and bases
- Be able to recognize acids and bases of each type
- Be able to rationalize the relative acidities of Bronsted acids
- Be able to interpret Pk in terms of relative acidity and basicity of Bronsted acids/bases
- Be able to use resonance structures to describe the effect of electron delocalization on acids and bases
When you have finished this chapter, you should
This chapter introduces us to chirality, the property of being non-superposable on one's mirror image. It involves much manipulation of 2-D images as if they were 3-D. Use your model kit both while reading the chapter and while working the problems.
When we have finished the Chapter, you should:
- Understand what chirality is and be able to recognize objects, including molecules, that are chiral
- Be able to use the IUPAC system for specifying the absolute configuration (handedness) of chiral molecules
- Students in the various "bio" disciplines will have encountered an earlier scheme for specifying configuration. Here is why it should be abandoned and wiped from the face of the planet:
- Be able to classify stereoisomers as enantiomers or diastereomers, and relate differences in their chemical and pysical properties to their classification
Here's the classification scheme and some problems:
- Be able to draw correct stereoprojections of chiral molecules
- Be able to describe the stereoisomerism of cycloalkane derivatives
- Be able to test for chirality using a symmetry plane, and use the plane to identify objects that are chiral without containing stereogenic centers
Here is a summary of the principal ideas in this chapter.
We're jumping out of order here to begin to answer the question, "How do they know the molecule looks like that?" How do we know the structures of the complex molecules we have been writing?
When you finish this Chapter, you should:
- Be able to describe qualitatively how a mass spectrometer works, including what happens to molecules when they are injected into one
- Be able to obtain molecular formulas from mass spectra
using the M, M+1, and M+2 peaks
- using exact masses
- Be able to describe qualitatively how an infrared spectrometer works, and how infrared radiation is absorbed by organic molecules
- Be able to use infrared spectra and data tables to:
- Identify functional groups
- Identify some skeletal features
Here is our table of 1H and 13C chemical shifts:
- Understand how radiofrequency radiation is absorbed by organic molecules
- Understand qualitatively how nmr measurements are performed
- Be able to judge qualitatively the relative absorption frequencies (the "chemical shifts") of both 1H and 13C nuclei
- Be able to get connectivity information from 1H-1H coupling
- Use 1H and 13C nmr data to solve molecular structures
Here's an outline of the basic procedure to use in solving structures: [CLICK]
When you have finished this chapter, you should be able to:
- Describe how bond breaking may occur homolytically and heterolytically
- Identify the kinds of carbo-based species produced by such bond breaking
- Use curly arrows to show electron flow during bond making and breaking
- Be able to use bond dissociation energies to calculate DH of reaction
- Explain the difference between equilibrium and rate of a chemical reaction
- Write the algebraic expressions describing equilibria and rates
- Draw potential energy diagrams for a variety of types of organic reactions
Chapters 7 and 8
We consider Chapters 7 and 8 together because the reactions in them are inseparable, largely occuring in the same reaction mixture at the same time. In your text, Chapter 7 focuses on substitution, Chapter 8 on elimination.
When you have finished these Chapters you should
- Write examples of the four mechanisms for nucleophilic substitution and elimination, using curly arrows to represent bond-making and bond-breaking steps accurately.
- Describe these reactions employing the "filled-empty" orbital interaction terminology
- Explain how the mechanism that occurs in a particular case is determined by:
- the structure of R
- the nature of the solvent
- the basicity of the nucleophile
- the basicity of the leaving group, X
- Predict the products, including stereochemistry, of these reactions for any given RX
- Examine the product of an SN or E reaction and determine the reactants from which it can be made
Use this flow chart to help in making predictions.
When we have finished this chapter you should be able to:
- Write equations for the synthesis of alcohols and ethers from alkyl halides and other organic molecules
- Write curly arrow mechanisms for the reactions involved in those syntheses
- Write equations for the dehyration of alcohols by strong acid and the conversion of alcohols to halides by HX
- Write curly arrow mechanisms for those reactions, including any carbocation rearrangements that may occur
- Explain the stereoselectivity and regioselectivity of the above reactions
- Write equations for the reactions of oxiranes with bases (nucleophiles), including stereochemistry, and for the acid-catalyzed ring opening of oxiranes.
- Write curly arrow mechanisms for both of those reactions that account for the difference in regio- and stereoselectivity.
- Provide systematic names for simple alcohols, ethers, and oxiranes
Here is a summary of reactions of alcohols; it includes some oxidation reactions that you will not see until next semester.
When we have finished this chapter, you should be able to:
- Name and specify the stereochemistry of alkenes by the IUPAC methods
- Write equations for the electronphilic additions of HX, X2, H2O (three ways), H2O+X2 including appropriate regio- and stereospecificity
- Write curly arrow mechanisms for those reactions, explaining the observed regio- and stereospecificity
- Write equations for the preparation of specific alcohols, selecting appropriate starting alkenes and reagents
Here is a summary of the reactions of alkenes; again, it includes some oxidation reactions that you will not see until next semester:
Here's how to use FLASHCARDS to learn reactions.
This page last modified 1:03 PM on Wednesday August 13th, 2014.
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