Term
| Are short bonds stronger or weaker than long bonds? |
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Definition
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Term
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Definition
| the degree to which an atom or group's electron cloud is deformed under the influence of an external electric field |
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Term
| Do more polarizable atoms/groups have higher or lower boiling points? |
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Definition
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Term
| nucleophilic substitution |
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Definition
| the reagent attacks the haloalkane & replaces the halide; an electrophilic carbon in haloalkanes reacts with the nucleophile (substance that contains an unshared electron pair) |
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Term
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Definition
| the ion that is displaced in a nucleophilic substitution (i.e. the halide) |
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Term
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Definition
| the organic starting material (i.e. the haloalkane) that is the target of attack by a nucleophile |
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Term
| If the nucleophile in a nucleophilic substitution is _____, then the substitution will result in a cationic species (+ charge) |
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Definition
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Term
| Why are halides unique in nucleophilic substitution? |
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Definition
| they may serve as leaving groups as well as nucleophiles, making some reactions reversible |
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Term
| Curved arrows _____ start at electron-deficient atoms, such as H+ |
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Definition
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Term
| The movement of a proton is depicted by an arrow pointing from _____ toward _____ |
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Definition
| an electron source (lone pair or bond); the proton |
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Term
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Definition
| the rate equation for a chemical process; established by comparing the rate of product formation beginning with several different concentrations of the starting materials |
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Term
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Definition
| rates are directly proportional to the concentrations of both substrate & nucleophile |
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Term
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Definition
| a mechanism in which the two reactants interact in a single step |
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Term
| bimolecular nucleophilic substitution/SN2 |
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Definition
| the general term applied to a bimolecular reaction; S = substitution, N = nucleophilic, 2 = bimolecular |
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Term
| In a bimolecular nucleophilic substitution, bond making takes place _____ as bond breaking |
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Definition
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Term
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Definition
| a reaction in which bond making & bond breaking occur "in concert" |
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Term
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Definition
| the nucleophile approached the substrate from the same side as the leaving group, one group exchanging for the other |
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Term
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Definition
| a reaction in which the nucleophile approaches carbon from the side opposite the leaving group |
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Term
| In SN2 reactions, is the formation of the transition state a separate step? |
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Definition
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Term
| In SN2 reactions, the transition state only describes the geometric arrangement of the reacting species as they pass through the _____ of a _____ process |
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Definition
| maximum energy point; single-step |
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Term
| Frontside displacement should give rise to a product with the _____ configuration of the substrate |
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Definition
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Term
| Backside displacement should furnish a product with the _____ configuration of the substrate |
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Definition
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Term
| All SN2 reactions proceed with _____ |
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Definition
| inversion of configuration |
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Term
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Definition
| a process whose mechanism requires that each stereoisomer of the starting material transform into a specific stereoisomer of product |
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Term
| retention of configuration |
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Definition
| the result of the double inversion sequence of two SN2 processes |
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Term
| In substrates bearing more than one stereocenter, where does inversion take place? |
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Definition
| only at the carbons that undergo reaction with the incoming nucleophile |
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Term
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Definition
| the relative rate at which a leaving group can be displaced; correlated with a leaving group's capacity to accommodate a negative charge |
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Term
| Leaving-group ability is inversely related to _____ |
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Definition
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Term
| Are weak or strong bases best able to accommodate negative charge and therefore are the best leaving groups? |
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Definition
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Term
| Good leaving groups are the _____ of strong acids |
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Definition
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Term
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Definition
| a nucleophile's relative nucleophilic strength |
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Term
| Of a pair of nucleophiles containing the same reactive atom, the species with _____ is the more powerful nucleophile |
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Definition
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Term
| Of a base and its conjugate acid, the _____ is always more nucleophilic |
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Definition
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Term
| What is the relationship between charge of an attacking species and reaction speed? |
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Definition
| the more negative the attacking species, the faster the reaction should be |
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Term
| What is the relationship between basicity and reactivity of a nucleophile? |
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Definition
| the more basic species is the more reactive nucleophile |
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Term
| In the progression from the left to the right of the periodic table, does nucleophilicity increase or decrease? |
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Definition
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Term
| Basicity is a _____ property, measured by an equilibrium constant "K" |
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Definition
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Term
| Nucleophilicity is a _____ phenomenon, quantified by comparing rates of reaction "k" |
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Definition
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Term
| Nucleophilicity _____ in the progression down the periodic table |
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Definition
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Term
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Definition
| solvents capable of hydrogen bonding |
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Term
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Definition
| solvents incapable of hydrogen bonding; opposite of protic |
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Term
| Why does nucleophilicity decrease down a column in the periodic table? |
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Definition
| Solvation weakens the smaller nucleophiles at the top of the column, but can't affect the bigger nucleophiles at the bottom of the column as well |
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Term
| Sterically bulky nucleophiles react _____ |
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Definition
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Term
| In aprotic solvents, the nucleophilicity of nucleophiles _____ down a group in the periodic table |
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Definition
| decreases (opposite of protic!!!) |
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Term
| The replacement of one hydrogen atom in a halomethane by a methyl group causes _____ |
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Definition
| significant steric hindrance & reduction of the rate of the SN2 reaction |
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Term
| What is the relative effect of branching at positions farther from the site of reaction? |
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Definition
| much smaller effect on the rate of reaction |
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