Term
|
Definition
|
|
Term
| the reason for handedness in molecules: |
|
Definition
|
|
Term
|
Definition
| molecules that contain no plane of symmetry and are not superimposeable on their mirror-images |
|
|
Term
|
Definition
| a C bonded to 4 different groups |
|
|
Term
| some groups that can't be chirality centers |
|
Definition
|
|
Term
| optically active substances |
|
Definition
| substances that, when in solution, rotate the plane of plane-polarized light |
|
|
Term
| the angle of rotation of optically active substances can be measured with... |
|
Definition
|
|
Term
| some things about a substance's rotation that can be measured |
|
Definition
|
|
Term
|
Definition
| a compound whose solution rotates plane-polarized light to the right |
|
|
Term
|
Definition
| a compound whose solution rotates plane-polarized light to the left |
|
|
Term
| the extent of rotation depends on... |
|
Definition
-concentration
-path length
-wave length |
|
|
Term
|
Definition
| the optical rotation of a chiral compound under standard conditions, such as concentration of 1g/mL, sample path length of 1 dm, and light of wavelength 589 nm |
|
|
Term
| rules for assigning configurations at a chirality center |
|
Definition
1: assign priorites to each group bonded to the C by using Cahn-Ingold-Prelog rules
2: orient the molecule so that the group of lowest priority is pointing to the rear
3: draw a curved arrow from group 1 to group 2 to group 3
4: if the arrow rotates clockwise, the chirality center is R, and if the arrow rotates counterclockwise, the chirality center is S |
|
|
Term
| how to assign priorites to each group bonded to the C by using Cahn-Ingold-Prelog rules |
|
Definition
1: rank each atom by atomic number (atoms with higher atomic numbers get higher priorities)
2: if a decision can't be reached based on the first atom, look at a second or third atom until a difference is found
3: multiple bonded atoms are equivalent to the same number as single bonded atoms |
|
|
Term
| is the sign of optical rotation related to R, S designation? |
|
Definition
|
|
Term
| how R, S designations have been proven to be correct |
|
Definition
|
|
Term
| a molecule with 2 chirality centers can have how many possible stereoisomers? |
|
Definition
|
|
Term
| depiction of the relationship between enantiomers and diastereoisomers |
|
Definition
| photograph figure 5-10 on p. 131 |
|
|
Term
|
Definition
| stereoisomers that are not mirror images |
|
|
Term
|
Definition
| diastereoisomers whose configuration differs at only 1 chirality center |
|
|
Term
|
Definition
| occurs when a compound with 2 chirality centers possesses a plane of symmetry |
|
|
Term
| a meso compound is ______ despite having 2 chirality centers |
|
Definition
|
|
Term
| a meso compound is achiral despite ______ |
|
Definition
| having 2 chirality centers |
|
|
Term
| racemic mixture (racemate) |
|
Definition
| a 50:50 mixture of 2 enantiomers |
|
|
Term
| the optical rotation of racemic mixtures |
|
Definition
|
|
Term
|
Definition
| differ in connections between atoms |
|
|
Term
|
Definition
| have different C skeletons |
|
|
Term
|
Definition
| contain different functional groups |
|
|
Term
|
Definition
| have functional groups in different positions |
|
|
Term
|
Definition
| have the same connections between atoms, but different geometry |
|
|
Term
| types of diastereoisomers |
|
Definition
-configurational diastereoisomers
-cis-trans isomers |
|
|
Term
| how cis-trans isomers differ |
|
Definition
| they differ in the arrangement of substituents on a ring or a double bond |
|
|
Term
| other elements that can be chirality centers |
|
Definition
| other elements wit tetrahedral atoms |
|
|
Term
|
Definition
| able to be converted from achiral to chiral in a single chemical step |
|
|
Term
| how to identify prochirality for a sp2 hybridized C |
|
Definition
| 1: draw the plane that includes the atoms bonded to that sp2 C
2: assign priorities to the groups bonded to that C
3: draw a curved arrow from group 1 to group 2 to group 3
4: the face of the plane on which the curved arrow rotates clockwise is the Re face
5: the face on which the arrow rotates counterclockwise is the Si face |
|
|
Term
| when an atom that is sp3 hybridized has a prochirality center |
|
Definition
| when it becomes a chirality center after one of its attached groups is replaced |
|
|
Term
| how to identify prochirality in an sp3 hybridized atom |
|
Definition
| 1: for CH2X, imagine a replacement of 1 H with deuterium
2: rank the groups, including deuterium
3: if the replacement leads to R chirality, the atom is pro-R
4: if the replacement leads to S chirality, the atom is pro-S |
|
|
Term
| when a C is not a stereocenter |
|
Definition
| when it has 2 of the same group attached to it |
|
|
Term
| how to determine whether the stereocenter has the R or S configuration |
|
Definition
1: give each of the 4 groups a number (1-4)
2: use the orientation of these numbers to determine the configuration |
|
|
Term
| how to assign numbers to the groups around a stereocenter |
|
Definition
1: make a list of the 4 atoms attached to the stereocenter
2: rank those atoms based on atomic number |
|
|
Term
|
Definition
| compound that has an internal plane of symmetry |
|
|
Term
| when compounds are chiral |
|
Definition
| when they have stereocenters and they and are not meso |
|
|
Term
|
Definition
| compound makes plane polarized light rotate clockwise |
|
|
Term
|
Definition
| compound makes plane polarized light rotate counterclockwise |
|
|
Term
|
Definition
rotates polarized light clockwise
given a minus (+) sign |
|
|
Term
|
Definition
rotates polarized light counterclockwise
given a minus (-) sign |
|
|
Term
| the number of stereoisomers a molecule with chirality centers can have |
|
Definition
| 2n stereoisomers, where n = # of chirality centers |
|
|
Term
|
Definition
| atom whose replacement leads to an R chirality |
|
|
Term
|
Definition
| atom whose replacement leads to an S chirality |
|
|
Term
|
Definition
| the face on which the arrows curve clockwise |
|
|
Term
|
Definition
| the face on which the arrows curve counterclockwise |
|
|
Term
| types of organic reactions |
|
Definition
-addition
-elimination
-substitution
-rearrangement |
|
|
Term
|
Definition
occur when 2 reactants add to form one product, with no atoms left over
A + B --> AB |
|
|
Term
|
Definition
occur when a single reactant splits into 2 products
AB --> A + B |
|
|
Term
|
Definition
occur when 2 reactants exchange parts to yield 2 new products
AB + CD --> AD + CB |
|
|
Term
|
Definition
occur when a single product undergoes a rearrangement of bonds to yield an isomeric product
ABCD --> DBCA |
|
|
Term
|
Definition
| describes the bonds broken and formed in a chemical reaction, and accounts for all reactants and products |
|
|
Term
| types of bond breaking in chemical reactions |
|
Definition
|
|
Term
|
Definition
| symmetrical bond breakinbg such that 1 electron remains with each fragment |
|
|
Term
|
Definition
|
|
Term
| heterolytic bond breaking |
|
Definition
| unsymmetrical bond breaking such that both electrons remain with one fragment and the other fragment has a vacant orbital |
|
|
Term
|
Definition
|
|
Term
| types of bond formation in chemical reactions |
|
Definition
-symmetrical
-unsymmetrical |
|
|
Term
| symmetrical bond formation |
|
Definition
| each reactant contributes 1 electron to a covalent bond |
|
|
Term
| depiction of symmetrical bond formation |
|
Definition
|
|
Term
| unsymmetrical bond formation |
|
Definition
| both electrons in a covalent bond come from 1 reactant |
|
|
Term
| depiction of unsymmetrical bond formation |
|
Definition
|
|
Term
|
Definition
-radical
-polar
-pericyclic |
|
|
Term
|
Definition
| involve symmetrical bond breaking and bond formation |
|
|
Term
|
Definition
| involve unsymmetrical bond breaking and bond formation |
|
|
Term
|
Definition
| reactant that contains an atom with an unpaired electron |
|
|
Term
| why radicals are highly reactive |
|
Definition
| because they contain an atom with an unpaired electron |
|
|
Term
| substitution reaction that involves a radical |
|
Definition
| occurs when a radical abstracts an atom and a bonding electron from another molecule |
|
|
Term
| addition reaction that involves a radical |
|
Definition
| occurs when a radical adds to a double bond |
|
|
Term
| steps in a radical reaction |
|
Definition
-initiation step
-propagation steps
-termination step |
|
|
Term
|
Definition
| produces radicals by the symmetrical clevage of a bond |
|
|
Term
|
Definition
| chain reaction where a radical abstracts an atom to produce a new radical and a stable molecule |
|
|
Term
|
Definition
|
|
Term
| how bond breaking and formation works in radical reactions |
|
Definition
| all bonds are formed and broken by reactions of species with odd numbers of electrons |
|
|
Term
| some characteristics of polar reactions |
|
Definition
-they occur as a result of differences in bond polarities within molecules
-electron-rich sites in 1 molecule react with electron-poor sites in another molecule
-the movement of electron pairs is shown by curved, fullheaded arrows
-the reacting species are nucleophiles and electrophiles
-many polar reactions can be explained in terms of acid-base reactions |
|
|
Term
| polar reactions occur as a result of... |
|
Definition
| differences in bond polarities within molecules |
|
|
Term
| the polarities within polar molecules are usually due to... |
|
Definition
| electronegativity differences between atoms |
|
|
Term
| electronegativity differences may also be due to... |
|
Definition
-interactions of functional groups with solvents
-interactions of functional groups with Lewis acids or bases |
|
|
Term
| if there's no real electronegativity difference between atoms in a molecule, how can that bond behave as a polar bond? |
|
Definition
| some bonds in which 1 atom is polarizeable may also behave as polar bonds |
|
|
Term
| the sites that react in polar reactions |
|
Definition
| the electron-rich sites in one molecule react with the electron-poor sites in another molecule |
|
|
Term
| the movement of an electron pair in a polar reaction is shown by... |
|
Definition
| a curved, fullheaded arrow |
|
|
Term
| the reacting spevcies in a polar reaction |
|
Definition
-nucleophile
-electrophile
-some compounds behave as both nucleophiles and electrophiles |
|
|
Term
|
Definition
| compound with electron-rich atom |
|
|
Term
|
Definition
| compound with electron-poor atom |
|
|
Term
| many polar reactions can be explained in terms of... |
|
Definition
|
|
Term
| an example of a polar reaction |
|
Definition
| addition of HBr to ethylene |
|
|
Term
| what type of addition is the addition of HBr to ethylene? |
|
Definition
|
|
Term
| the behavior of the π electrons in ethylene in the addition of HBr to ethylene |
|
Definition
| the π electrons in ethylene behave as a nucleophile |
|
|
Term
| how the reaction of the addition of HBr to ethylene begins |
|
Definition
| the attack of the π electrons on the electrophile H+ |
|
|
Term
| what happens at the end of the reaction of the addition of HBr to ethylene? |
|
Definition
| the resulting intermediate carbocation reacts with Br- to form bromoethana |
|
|
Term
| rules for using curved arrows in polar reaction mechanisms |
|
Definition
-electrons must move from nucleophile to electrophile
-nucleophile can be negative or neutral
-electrophile can be positive or neutral
-the octet rule must be followed |
|
|
Term
| how chemical reactions can be expressed as equilibria |
|
Definition
| all chemical reactions are equilibria that can be expressed by an equilibrium constant (Keq) that shows the ratio of products to reactants |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| what must the energy be for the reaction to proceed as written? |
|
Definition
| to proceed as written, the energy of the products must be lower than the energy of the reactants |
|
|
Term
| the energy change that occurs during a reaction is described by... |
|
Definition
| ΔG°, the Gibbs free-energy change |
|
|
Term
| favorable reaction (spontaneous) |
|
Definition
| have negative ΔG° and are exothermic |
|
|
Term
| unfavorable reaction (nonspontaneous) |
|
Definition
| have positive ΔG° and are endothermic |
|
|
Term
| the relationship between ΔG° and Keq |
|
Definition
|
|
Term
|
Definition
| enthalpy, which is a measure of the total change in bonding energy during a reaction |
|
|
Term
|
Definition
| the reaction is exothermic |
|
|
Term
|
Definition
| the reaction is endothermic |
|
|
Term
|
Definition
| entropy, which is a measure of the freedom of motion of a reaction |
|
|
Term
| rxn with positive entropy |
|
Definition
| produces 2 product molecules from 1 reactant molecule |
|
|
Term
| rxn with negative entropy |
|
Definition
| produces 1 product molecule from 2 reactant molecules |
|
|
Term
| relationship between ΔG°, ΔH°, and ΔS° |
|
Definition
|
|
Term
| bond dissociation energy (D) |
|
Definition
| measures the heat needed to break a bond to produce 2 radical fragments |
|
|
Term
| what happens to the strength of bonds in exothermic reactions? |
|
Definition
| the bonds formed are stronger than the bonds broken |
|
|
Term
| what reaction energy diagrams show |
|
Definition
| the energy changes that occur during a reaction |
|
|
Term
| how a reaction energy diagram is set up |
|
Definition
| vertical axis represents energy changes and horizontal axis represents the progress of the reaction |
|
|
Term
| the highest energy species in a reaction |
|
Definition
|
|
Term
| can a reaction have more than 1 transition state? |
|
Definition
|
|
Term
| the energy of activation (ΔG‡) |
|
Definition
| the difference in energy between the reactants and the transition state |
|
|
Term
| values of ΔG‡ range from... |
|
Definition
|
|
Term
| what a reaction can do after reaching the transition state |
|
Definition
| it can go on to form products or revert to starting material |
|
|
Term
|
Definition
| in a reaction of at least 2 steps, this is the species that lies at the energy minimum between 2 transition states |
|
|
Term
| energy of an intermediate |
|
Definition
| even though it lies between 2 transition states, it is a highg energy species |
|
|
Term
| can an intertmediate be isolated? |
|
Definition
|
|
Term
| the solvents laboratory reactions are carried out in |
|
Definition
|
|
Term
| the medium biological reactions occur in |
|
Definition
|
|
Term
| the temperatures laboratory reactions take place in |
|
Definition
| a wide range of temperatures |
|
|
Term
| the temperatures biological reactions take place in |
|
Definition
| the temperature of the organism, usually within narrow limits |
|
|
Term
| the catalyzing in laboratory reactions |
|
Definition
| uncatalyzed or use simple catalysts |
|
|
Term
| the catalyzing in biological reactions |
|
Definition
|
|
Term
| description of laboratory reagents |
|
Definition
|
|
Term
| description of biological reagents |
|
Definition
| involve large, complex coenzymes |
|
|
Term
| specificity of biological reactions |
|
Definition
| they have high specificity for substrate |
|
|
Term
| specificity of laboratory reactions |
|
Definition
| they are relatively nonspecific |
|
|
Term
| are atoms w/ vacant orbitals electrophiles or nucleophiles? |
|
Definition
|
|
Term
| a type of rxn that has a carbocation intermediate |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| activation energy vs. speed of rxn |
|
Definition
| the higher the activation energy, the slower the rxn |
|
|
Term
| are pi bonds electrophiles or nucleophiles? |
|
Definition
|
|
Term
| are aromatic rings electrophiles or nucleophiles? |
|
Definition
|
|
Term
| the difference between exothermic and exergonic |
|
Definition
exothermic = -ΔH°
exergonic = -ΔG° |
|
|
Term
| the difference between endothermic and endergonic |
|
Definition
endothermic = +ΔH°
endergonic = +ΔG° |
|
|
Term
| location of transition state in energy diagram |
|
Definition
|
|
Term
| location of intermediate in energy diagram |
|
Definition
|
|
Term
|
Definition
| hydrocarbon that contains a C=C bond |
|
|
Term
| the 2 most important organic chemicals produced industrially |
|
Definition
|
|
Term
| how ethylene, propylene, and butylene are synthesized |
|
Definition
|
|
Term
|
Definition
| involves homolytic breaking of C-H and C-C bonds |
|
|
Term
| thermal cracking reactions are dominated by... |
|
Definition
|
|
Term
|
Definition
| describes the number of multiple bonds and/or rings in a molecule |
|
|
Term
| how to calculate the degree of unsaturation of a compound |
|
Definition
1: determine the equivalent hydrocarbon formula of the compound
2: add the number of halogens to the number of H's
3: subtract 1 H for every N
4: ignore the number of O's
5: calculate the number of paire of H's that would be present in an alkane that has the same number of C's as the equivalent hydrocarbon of the compound of interest. te difference is the degree of unsaturation. |
|
|
Term
|
Definition
| 1: find the longest chain containing the 2bl bond, and name it using "ene" as the suffix
2: number the C atoms in the chain, beginning at the end nearer the double bond
3: number the substituents and write the name
4: for cycloalkenes, the double bond is between C1 and C2, and substituents receive the lowest possible numbers
5: a -CH2- substituent is a methylene group, a H2C=CH- group is a vinyl group, and a H2C=CHCH2- group is an allyl group |
|
|
Term
| the hybridization of VC atoms in a double bond |
|
Definition
|
|
Term
| the bonds formed in the 2bl bond between 2 C's |
|
Definition
| 1 sigma bond and 1 pi bond |
|
|
Term
| does free rotation occur around 2bl bonds? |
|
Definition
|
|
Term
|
Definition
| disubstituted alkene that has substituents on the same side of the double bond |
|
|
Term
| trans isomer of an alkene |
|
Definition
| disubstituted alkene that has substituents on different sides of the double bond |
|
|
Term
| do cis and trans isomers of alkenes interconvert? |
|
Definition
| no because of the rigidity of the 2bl bond |
|
|
Term
| when cis-trans isomerism in an alkene doesn't occur |
|
Definition
| when one C in the 2bl bond is bonded to identical substituents |
|
|
Term
| what the E, Z system of isomerism is used for |
|
Definition
| it's used to describe the arrangement of substituents around a 2bl bond that can't be described by the cis/trans system |
|
|
Term
|
Definition
1: for each 2bl bonded C, rank its substituents by atomic number (kinda like you assign priorities in R and S configurations)
2: if a decision can't be reached based on the 1st atom, look at the 2nd or 3rd atom until a difference is found
3: multiple bonded atoms are equivalent to the same number of single bonded atoms |
|
|
Term
|
Definition
| has the higher ranked groups on the same side of the 2bl bond |
|
|
Term
|
Definition
| has the higher ranked groups on opposite sides of the double bond |
|
|
Term
| which alkenes are more stable, cis or trans? |
|
Definition
|
|
Term
| why are trans alkenes more stable than cis alkenes? |
|
Definition
| because cis alkenes have steric strain between the double bond substituents |
|
|
Term
| stabilities of alkenes can be determined experimentally by measuring... |
|
Definition
-cis-trans e'librium constants
-heats of hydrogenation |
|
|
Term
| the most useful method for determining the stability of alkenes |
|
Definition
| by measuring the heats of hydrogenation |
|
|
Term
| heat of hydrogenation of a cis isomer vs that for a trans isomer |
|
Definition
| the heat of hydrogenation of a cis isomer is a larger negative number thatn the heat of hydrogenation of a trans isomer |
|
|
Term
| which alkene is of higher energy, cis or trans isomer? |
|
Definition
|
|
Term
| alkene 2bl bonds become more stable with... |
|
Definition
|
|
Term
| why alkene 2bl bonds become more stable with increasing substitution |
|
Definition
| -hyperconjugation
-more substituted double bonds have more of the stronger sp2-sp3 bonds |
|
|
Term
|
Definition
| stabilizing interaction between the antibonding pi orbital of the C-C bond and a filled C-H sigma orbital oh an adjacent substituent |
|
|
Term
| electrophilic addition reactions |
|
Definition
| addition of an electrophile to a C=C bond to yield a saturated product |
|
|
Term
| mechanism of the electrophilic addition of H-X to alkenes |
|
Definition
| 1: the electrons of the nucleophilic pi bond attack the H atom of the electrophile H-X (X = Cl, Br, I, OH)
2: 2 electrons from the pi bond form a new sigma bond between -H and an alkene C
3: the carbocation intermediate reacts with X- to form a C-X bond |
|
|
Term
| description of the energy diagram for the electrophilic addition of H-X to alkenes |
|
Definition
-has 2 peaks separated by a valley (carbocation intermediate)
-the reaxtion is exothermic
-the first step is slower than the second step |
|
|
Term
| Markovinikov's rule of orientation of addition reactions |
|
Definition
-in the addition of HX to a double bond, H attaches to the C with fewer substituents and X attaches to the C with more substituents (regiospecific)
-if the C's have the same number of substituents, a mixture of products results |
|
|
Term
|
Definition
| describes a reaction that occurs with a specific regiochemistry to give a single product rather than a mixture of products |
|
|
Term
| the structure of carbocations |
|
Definition
| planar; the unoccupied p orbital extends above and below the plane containing the cation |
|
|
Term
| the stability of carbocations increases with... |
|
Definition
|
|
Term
| carbocation stability can be measured by... |
|
Definition
| studying gas phase dissociation enthalpies |
|
|
Term
| carbocations can be stabilized by... |
|
Definition
-inductive effects ofg neighhboring alkyl groups
-hyperconjugation |
|
|
Term
| how a carbocation can be stabilized by hyperconjugation |
|
Definition
| the mnore alkyl groups on the carbocation, the more opportunities there are for hyperconjugation |
|
|
Term
|
Definition
| postulate stating that we can get a picture of what a given transition state looks like by looking at the structure of the nearest stable species |
|
|
Term
| exothermic reactions have transition states that resemble... |
|
Definition
|
|
Term
| endothermic reactions have transition states that resemble... |
|
Definition
|
|
Term
| why the transition state for an endothermic step resembles the product of that step |
|
Definition
| because it is closer in energy |
|
|
Term
| why the transition state for an exothermic step resembles the reactant of that step |
|
Definition
| because it is closer in energy |
|
|
Term
| in an electrophilic addition reaction, the transition state for alkene protonation resembles... |
|
Definition
| the carbocation intermediate |
|
|
Term
| more stable carbocations form faster because... |
|
Definition
| their transition states are also stabilized |
|
|
Term
| reactions in which products from carbocation rearrangements are formed |
|
Definition
| some electrophilic addition reactions |
|
|
Term
| the formation of products from carbocation rearrangements supports... |
|
Definition
| the 2 step electrophilic addition mechanism, in which an intermediate carbocation is formed |
|
|
Term
| how intermediate carbocations can rearrange to more stable carbocations |
|
Definition
-a hydride shift
-an alkyl shift |
|
|
Term
|
Definition
| the shift of a H atom and its electron pair to a nearby cationic center |
|
|
Term
|
Definition
| the shift of an alkyl group with its electron pair to a nearby cationic center |
|
|
Term
| why a compound with an OH group has a higher boiling point than an otherwise identical compound with a lone O |
|
Definition
|
|
Term
| stability vs. ΔHcombustion |
|
Definition
|
|
Term
| energy of bond vs. size of atoms involved |
|
Definition
|
|
Term
| what kind of addition is it when alkene double bonds add to a carbocation? |
|
Definition
|
|
Term
| how rings contribute to unsaturation |
|
Definition
| each ring is an extra degree of unsaturation |
|
|
Term
| when numbering the carbons in a chain, what gets priority? functional group or branching? |
|
Definition
|
|
Term
| when to put a number next to the E or Z |
|
Definition
| when there's more than 1 alkene in a chain |
|
|
Term
| nucleophilic substitution |
|
Definition
| swapping of 1 functional group for another |
|
|
Term
| rate of nucleophilic substitution reaction depends on... |
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Definition
| concentration of both nucleophile and alkyl halide |
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Term
| solvents in which reaction occurs faster |
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Definition
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Term
| rate law for nucleophilic reactions |
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Definition
| rate = k [substrate][nucleophile] |
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Term
| why polar solvents are better thannonpolar solvents for reactions to occur in |
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Definition
| because of the charges involved |
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Term
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Definition
-polar protic
-polar aprotic |
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Term
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Definition
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Term
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Definition
| bas a dipole moment but can't H bond |
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Term
| why the reactivity of halides in polar aprotic solvents reverses (F- > Cl- > Br- > I-) |
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Definition
| because there is no H bonding to solvent |
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Term
| what makes a good leaving group? |
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Definition
| leaving groups are weal bases |
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Term
| steric bulk on a particular atom vs. that atom's nucleophilicity |
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Definition
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Term
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Definition
| the loss of a leaving group from the alpha C and a H from the beta C resulting in the formation of a double bond |
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Term
| why the major product of an elimination reaction is the more substituted alkene |
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Definition
| because alkenes become more thermodynamically stable as C-H bonds are replaced with C-C bonds |
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Term
| periodic trand in bacisity |
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Definition
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Term
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Definition
2 groups on adjacent C's oriented at 180° to each other
[image] |
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Term
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Definition
2 groups on adjacent C's oriented 0° to each other
[image] |
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Term
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Definition
2 groups on adjacent C's oriented 60° to each other
[image] |
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Term
| eclipsed (stereochemistry) |
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Definition
when all 3 substituents overlap completely with all 3 substituents on a neighboring C
[image] |
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Term
| staggered (stereochemistry) |
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Definition
when all 3 substituents on a C are arranged at a 60° angle to all 3 substituents on another C
[image] |
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Term
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Definition
| 50:50 mixture of 2 enantiomers |
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Term
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Definition
| molecule with chiral centers, but has a plane of symmetry that makes the molecule achiral |
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Term
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Definition
| strain that arises from the proximity of bonds (and the electrons in them) - generally eclipsing |
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Term
| difference between conformational isomers |
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Definition
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Term
| physical properties of conformational isomers |
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Definition
| identical, as long as they can interconvert thru bond rotation |
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Term
| difference between constitutional isomers |
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Definition
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Term
| physical properties of constitutional isomers |
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Definition
| different boiling points, melting points, and other physical properties |
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Term
| difference between stereoisomers |
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Definition
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Term
| physical properties of enantiomers |
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Definition
| identical, but differ in optical rotation |
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Term
| physical properties of diastereomers |
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Definition
| different boiling points, melting points, etc. |
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Term
| another name for stereoisomers |
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Definition
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Term
| what happens to the axial and equatorial groups when the chair flips? |
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Definition
| the axial groups become equatorial and the equatorial groups become axial |
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Term
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Definition
| atoms or molecules that contain an unpaired electron in their valence shell |
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Term
| why free radicals are highly reactive |
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Definition
| because they contain less than a full octet of electrons |
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Term
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Definition
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Term
| what stabilizes free radicals? |
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Definition
the same factors that stabilize carbocations
-substitution
-resonance
-with adjacent lone pairs
-polarizability
-hybridization
-electron-withdrawing groups |
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Term
| electron-poor species, like radicals, are stabilized by... |
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Definition
| electron rich neighbors or being able to spread electron density over a greater volume |
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Term
| substituted radicals in order of stability |
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Definition
| tertiary > secondary > primary > methyl radical |
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Term
| how resonance can stabilize radicals |
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Definition
| radicals are stabilized if they can be delocalized over several atoms (as in resonance) |
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Term
| how adjacent lone pairs stabilize free radicals |
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Definition
hyperconjugation
stability increases with increasing donor ability of atom with lone pairs |
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Term
| how polarizability stabilizes free radicals |
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Definition
| stability increases with increasing size of the atom |
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Term
| how hybridization affects free radical stability |
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Definition
| stability increases with decreasing s-character, which moves the free radical further from the nucleus |
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Term
| stability of free radical vs. s-character |
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Definition
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Term
| electron-withdrawing groups |
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Definition
| groups that withdraw electron density from the free radical (without being able to donate a lone pair); they destabilize radicals |
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Term
| bond strength vs. kcal/mol |
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Definition
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Term
| how electron movement is shown in homolytic cleavage |
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Definition
| using "single-barbed" arrows |
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Term
| the arrows used to show electron movement in resonance of free radicale |
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Definition
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Term
| the 3 key mechanistic steps in free radical halogenation |
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Definition
-initiation
-propagation
-termination |
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Term
| initiation phase of free radical halogenation |
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Definition
| homolytic cleavage of bond between halogen atoms |
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Term
| propagation phase of free radical halogenation |
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Definition
| step in the free radical reaction that starts with free radicals from the initiation phase yields free radicals |
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Term
| termination phase of free radical halogenation |
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Definition
| free radicals bonding to each other such that there are no free radicals left |
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Term
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Definition
they generate free radicals when heated
they usually have a weak bond (such as O-O) that readily undergoes homolytic cleavage |
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Term
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Definition
| C wit 3 H attached; basically primary C |
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Term
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Definition
| C with 2 H attached; basically secondary C |
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Term
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Definition
| C with 1 H attached; basically tertiary C |
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Term
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Definition
| C with 0 H attached; basically quartenary C |
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Term
| how many lines to draw on the 13C spectrum |
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Definition
| the number of unique C's plus symmetrical pairs |
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Term
| when to make a line on the 13C spectrum short |
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Definition
| when there's no H attached to it |
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Term
| the lines to put to the left of 100 ppm on the 13C spectrum |
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Definition
| the ones associated with the sp2 hybridized C's |
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Term
| the lines to put to the right of 100 ppm on the 13C spectrum |
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Definition
| the ones associated with the sp3 hybridized C's |
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Term
| rate law in electrophilic reactions |
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Definition
| rate = k [alkene][electrophile] |
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Term
| Hammond's postulate basically says... |
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Definition
| the transition state most closely resembles product or reactant, whichever is closest in energy to the transition state |
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Term
| anything can move during a rearrangement, as long as... |
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Definition
| it's moving towards more stable carbocation |
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Term
| going from less stable to more stable is (endothermic or exothermic)? |
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Definition
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Term
| why one possible reactant might be a better option than other possible reactants for the same product |
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Definition
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Term
| where to put the sp3 C's attached to halogens on the 13C spectrum |
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Definition
| between the 100 and the C's to the far right |
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Term
| where to put the sp2 C's attached to O on the 13C spectrum |
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Definition
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Term
| where to put the sp2 C's on the 13C spectrum |
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Definition
| a little to the left of 100ppm |
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Term
| the range of the 13C spectrum |
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Definition
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Term
| orientation of the 13C spectrum |
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Definition
| 200 on left, 0 on right, and 100 in middle |
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Term
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Definition
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Term
| generic rate law for electrophilic addition |
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Definition
| rate = k [alkene][electrophile] |
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Term
| how C's in a chain can be electrophilic centers |
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Definition
| if there's a partial positive charge on them due to dipole moment caused by polarity of what they're bonded with |
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Term
| how bonds are broken in polar reactions |
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Definition
| heterolytically (electron pair moves instead of single electron) |
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Term
| where to put the sp C's in the 13C NMR spectrum |
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Definition
| in the middle, straddling the 100ppm in the middle |
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Term
| where to put the sp3 C's in the 13C NMR spectrum |
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Definition
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Term
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Definition
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Term
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Definition
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Term
| the alkene expected to react faster in an electrophilic addition reaction based on Hammond's postulate |
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Definition
| the one that yields a more stable carbocation |
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Term
| can ring C double bonds isomerize? |
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Definition
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