CHE 171: Specific Objectives for Quizzes and Exams

For Quiz 1:

1. Know why atoms form bonds and what types of bonds they form based on relative electronegativity (or electropositivity).
2. Be able to draw good Lewis dot structures (or Lewis structures) given a molecular formula; also be able to calculate formal charge and incorporate this into your Lewis structures where applicable.
3. Be aware that there may be two (or more) ways to connect the atoms of a given molecular formula (constitutional isomers) and be able to draw Lewis structures for them.
4. Understand the concept of resonance and be able to show contributing resonance structures for a compound whose electrons may be delocalized.
5. Be able to predict bond angles and geometry for designated atoms within a molecule.
6. Understand the concept of hybridization and be able to predict the hybridization of indicated atoms within a given molecule.

For Quiz 2:

1. Be able to draw organic compounds as condensed structures and skeletal structures (bond line form).
2. Understand trends associated with bond length and strength and know the relative lengths and strengths of common types of C-C bonds and C-H bonds.
3. Know what electronegativity is and how to predict the relative electronegativity values of atoms.
4. Be able to recognize polar bonds.
5. Be able to predict whether or not a molecule is polar based on the bonds present and the overall geometry.
6. Understand what constitutes Bronsted acids and bases.
7. Be able to show electron flow (curved arrow notation) for an acid-base reaction.
8. Understand what pKa is and how pKa values correspond to relative acid strength.
9. Be able to predict the outcome of a given acid-base reaction (in which direction does the equilibrium lie?).
10. Understand how the following factors affect acid strength: elemental/periodic trends, induction, resonance, hybridization.
11. Be able to rank a given set of compounds in terms of increasing or decreasing acidity (or basicity).
12. Be able to recognize acidic and basic components (or sites) of a given molecule (see, for example, morphine on the top of page 56 in Smith)

For Quiz 3:

1. Understand why atoms form bonds and what types of bonds they form based on relative electronegativity (or electropositivity).
2. Be able to draw good Lewis dot structures (or Lewis structures) given a molecular formula; also be able to calculate formal charge and incorporate this into your Lewis structures where applicable.
3. Be aware that there may be two (or more) ways to connect the atoms of a given molecular formula (constitutional isomers) and be able to draw Lewis structures for them.
4. Understand the concept of resonance and be able to show contributing resonance structures for a compound whose electrons may be delocalized.
5. Be able to predict bond angles and geometry for designated atoms within a molecule.
6. Understand the concept of hybridization and be able to predict the hybridization of indicated atoms within a given molecule.
7. Be able to draw organic compounds as condensed structures and skeletal structures (bond line form).
8. Understand trends associated with bond length and strength and know the relative lengths and strengths of common types of C-C bonds and C-H bonds
9. Know what electronegativity is and how to predict the relative electronegativity values of atoms.
10. Be able to recognize polar bonds.
11. Be able to predict whether or not a molecule is polar based on the bonds present and the overall geometry.
12. Understand what constitutes Bronsted acids and bases.
13. Be able to show electron flow (curved arrow notation) for an acid-base reaction.
14. Understand what pKa is and how pKa values correspond to relative acid strength.
15. Be able to predict the outcome of a given acid-base reaction (in which direction does the equilibrium lie?).
16. Understand how the following factors affect acid strength: elemental/periodic trends, induction, resonance, hybridization.
17. Be able to rank a given set of compounds in terms of increasing or decreasing acidity (or basicity).
18. Be able to recognize acidic and basic components (or sites) of a given molecule (see, for example, morphine on the top of page 56 in Smith).
19. Understand what constitutes a Lewis acid (electrophile) and Lewis base (nucleophile).
20. Be able to show how (curved arrow notation) a given electrophile reacts with a given nucleophile; be able to show the product(s) of such a reaction.
21. Know what a heteroatom is.
22. Know what a “functional group” is in organic chemistry.
23. Understand the following classes of organic compounds: hydrocarbons (all types), “C-Z” compounds, “C=O” compounds.
24. Be able to recognize the following types of organic compounds: alkyl halides, alcohols, ethers, amines, aldehydes, kektones, carboxylic acids, esters, amides, and acid chlorides; be able to recognize the corresponding functional groups within larger molecules.
25. Be able to recognize and classify the three types of intermolecular forces; understand what gives rise to these forces and what effects they have on physical properties like BP, MP, and solubility.
26. Be able to recognize electron-rich and electron deficient sites in a molecule and predict whether or not two compounds will react based only on their relative electron densities.

For Quiz 4:

1. Know the three types of alkanes we discussed in class: straight chain, branched and cyclic and their corresponding empirical molecular formulas.
2. Be able to classify carbon atoms as 1°, 2°, 3°, or 4°; be able to classify hydrogen atoms as 1°, 2°, or 3°.
3. Know the IUPAC names for the straight chain alkanes with 1 to 10 carbon atoms (and the corresponding alkyl groups, e.g. methyl, ethyl, propyl, etc.).
4. Be able to name all kinds of alkanes using the IUPAC system; be able to draw a bond-line (skeletal) structure for an alkane given its IUPAC name.
5. Know the following common names: isopropyl, tert-butyl, sec-butyl, isobutyl.
6. Understand the trends associated with physical properties of alkanes (BP, MP, solubility).
7. Be able to draw and interpret Newman projections sighting down particular bonds of a molecule.
8. Be able to draw a diagram of and explain the energetics associated with rotation around s bonds of a molecule (butane and other straight-chain or branched alkanes, for example).
9. Understand and be able to explain or define the following terms as they apply to conformational analysis: staggered, eclipsed, anti, gauche, torsional strain, steric strain, angle strain, energy barrier, "ring flipping," puckered, chair, boat.
10. Be able to accurately draw cyclohexane chair conformations with axial and equatorial substituents, and assess the relative energies of these. Understand why the cyclohexane chair conformation is so stable (low in energy).
11. Understand the differences between cis and trans isomers of di-substituted ring systems.
12. Be able to draw and understand the conformational analysis associated with di-substituted cyclohexanes [cis- or trans-(1,2); cis- or trans-(1,3); cis- or trans- (1,4)].

For Quiz 5:

1. Know what a stereogenic centers are and be able to identify them in a given moleculee.
2. Be able to determine whether or not a molecule is chiral (look for the presence of stereogenic center(s) and the absence of any planes of symmetry).
3. Be able to determine the absolute configuration (R or S) of a stereogenic center.
4. Know what it means for a molecule to be optically active and how optical activity is measured.
5. Know how to calculate the specific rotation [a] of a sample given its observed rotation, concentration, and the path-lenght of the sample tube.
6. Be able to calculate optical purity (enantitomeric excess or ee) of an optically active sample and determine how much of each enantiomer is present in a mixture.
7. Be able to draw all of the possible stereoisomers for a given molecule (maximum possible stereoisomers = 2^n, where n = # of stereogenic centers.
8. Be able to recognize the relationship between two stereoisomers as enantiomeric or diastereomeric.
9. Know what a meso compound is and be able to recognize one.

For Quiz 6:

1. Be able to recognize and classify the following types of organic reactions: (a) acid-base or proton transfer; (b) reduction; (c) oxidation; (d) substitution; (e) elimination; (f) addition.
2. Know the difference between a concerted mechanism and one that is step-wise.
3. Know the two ways that a covalent bond can break or form (heterolytically or homolytically) and be able to show each using the proper curved-arrow notation.
4. Know what constitutes a reaction intermediate and a transition state and the difference between the two.
5. Know what is meant by “bond dissociation energy,” and be able to asses the strength of a bond given its DH° value.
6 . Know what the Gibbs free energy (DG°) of a reaction is and be aware that for many organic reactions DG° ~ DH°.
7. Know that a -DG° and a -DH° correspond to an exothermic reaction (products are lower in energy than reactants and equilibrium is shifted towards product); be aware that the reverse is also true.
8. Know that for a reaction to be practical, it must be thermodynamically favorable (equilibrium favors products) AND kinetically favorable (product is formed at a reasonable rate).
9. Be aware that a -DG° and a -DH° correspond to a Keq > 1 and that a a +DG° and a +DH° correspond to a Keq < 1.
10. Know that small changes in energy correspond to large changes in the ratio or reactants:products at equilibrium.
11. Know that thermodynamics tell us whether or not a reaction CAN occur, but kinetics tell us whether or not it will occur (at a reasonable rate) and that these are two independent considerations; i.e. a reaction may be thermodynamically favored (-DH°) but not kinetically favored (very large Ea).
12. Be able to read, interpret (is the reaction endo- or exothermic? is it fast or slow?), and/or draw energy level diagrams for a given reaction.
13. Know what the activation energy (Ea) of a reaction is and that the greater the activation energy the slower the reaction.
14. Know that kinetics is the study of reaction rates, and know what a reaction rate is and how it is expressed.
15. Be able to write a rate equation for a given reaction and assess whether the reaction is first order (unimolecular) or second order (bimolecular).
16. Know what factors can affect a reaction rate and to what extent.
17. Know what a catalyst is and how a catalyst affects the rate of a reaction.

For Quiz 7:

1. Be able to differentiate between methyl-, 1°, 2°, 3°, alkyl halides, allyl (allylic), benzyl (benzylic), vinyl (vinylic) halides and know which ones undergo nucleophilic substitution and/or elimination reactions.
2. Be able to name alkyl halides (or halo alkanes) using the IUPAC system or common names (including stereochemistry where applicable).
3. Know the general requirements for a substitution reaction and be able to identify the “substrate”, the “nucleophile” and the “leaving group” for a given substitution reactiton.
4. Know what constitutes a good leaving group and be able to assess relative leaving group ability.
5. Know what constitutes a good nucleophile and be able to assess relative nucleophile strength; know that nucleophile strength and base strength are directly proportional except when the nucleophile is sterically hindered and/or when the reaction is conducted in polar protic solvent (like water or alcohols).
6. Be able to predict whether an equilibrium favors products or reactants based on the relative basicities of the leaving group and nucleophile.
7. Know the difference between polar protic and aprotic solvents.
8. Know what a mechanism is.
9. Be able to show (arrow pushing) SN2 and SN1 mechanisms and know the differences between the two.
10. Know that an SN2 reaction at a stereogenic center proceeds with inversion of configuration because bond-making and bond-breaking occur simultaneously with backside attack of the nucleophile.
11. Know that an SN1 reaction at a stereogenic center proceeds with racemization (loss of optical activity) because the nucleophile may attack either face of the planar carbocation intermediate.
12. Know that the order of reactivity for an SN2 reaction is methyl-X > 1° > 2° (3° substrates do not undergo SN2 reactions); the reverse is true for SN1 reactions 3° > 2° (1° and methyl substrates do not undergo SN1 reactions because they cannot form stable carbocation intermediates).
13. Know that the SN2 mechanism is favored in the presence of strong nucleophiles and polar, aprotic solvents and that the SN1 mechanism is favored in the presence of weak nucleophiles and polar protic solvents.
14. Be able to predict whether a substitution reaction will proceed via an SN2 or SN1 mechanism based on the substrate, nucleophile, and solvent.

For Quiz 8:

1. Be able to predict whether a substitution reaction will proceed via an SN2 or SN1 mechanism; be able to show the mechanism (curved arrows) and a corresponding energy profile and rate law.
2. Know and be able to show how stereochemistry is affected when a substituion reaction occurs at a chirality center (via either the SN2 or SN1 mechanisms).
3. Know that it is possible to convert an alkyl halides to esters, ethers, alcohols, azides, amines, and nitriles through substitution reactions and that these transformations constitute synthetic "tools".
4. Know what synthesis is, what retrosynthetic analysis is and be able to devise a simple synthesis (via retrosynthetic analysis) for a given target compound; be able to assess several synthetic routes to a particular target compound.
5. Be able to classify alkenes (un-, mono-, di- (cis, trans, or gem), tri-, or tetra-substituted); know the relative stability of alkenes (the more substituted the more stable).
6. Know and be able to show the two different mechanisms for elimination (E2 and E1), including energy profiles, transition states, and rate laws.
7. Know what the Zaitsev rule is and be able to apply it when determining the major and minor products that will result from an elimination reaction where the alkyl halide has several types of abstractable b-protons.