O Chem CH 6-7

addition

addition

reaction where 2 reactants combine to form 1 product

elimination

reaction where 1 reactant splits into 2 products

Substitution

reaction where 2 reactants exchange parts to form 2 new products

rearrangement

reaction where single reactant yielding an isomeric product through reorganization of its bonds and atoms

reaction mechanism

a detailed description of how a reaction occurs

bond

chemical reactions involve --- breaking and --- making

homolytic

symmetrical cleavage, when one electron goes to each part of the bond breakage

heterolytic

unsymmetrical cleavage, the breaking of a covalent bond with both of the bonded electrons going to one of the atom

1/2

arrow heads with a --- head indicate movement of 1 electron in the symmetrical process

complete

arrow heads with a --- head indicate movement of 2 electrons in the unsymmetrical process

radical reactions

processes that involve symmetrical bond-breaking and bond-making, react to complete an octet

radical

neutral chem species containing odd numbers of electrons, has a single unpaired electron in 1 of its orbital

polar reactions

processes that involve unsymmetrical bond-breaking and bond-making, more common than radical reactions

initiation

The first step in a radical substitution in which the free radicals are generated, Cl2 ---> 2Cl

propagation

reaction to form a new radical

termination

combo of 2 radicals yielding a stable product

unsymmetrical

polar reaction molecules can contain local --- electron distribution - causes bond polarity

polar

bonds in functional groups are ---

positive

carbon atoms bonded to electronegative atoms have partial --- charge

negative

carbon atoms bonded to metals have a partial --- charge

Polarizability

Tendency of atoms in a molecule to undergo polarization

larger

--- atoms, easily polarizable

smaller

--- atoms, less polarizable

nucleophile

electron rich species that donate electron pairs, a lewis base

Electrophile

electron pair acceptor, lewis acid

double

--- bond is more accessible to approaching reactants than a single bond

Carbocation

substances that contain a trivalent positive charged Carbon having 6 electrons in its outer shell

neutrophilic, electrophilic

electrons move from a --- source to a --- source

[products]/[reactants]

Keq=

Keq > 1

lots of products

Keq < 1

lots of reactants

Keq = 1

products = reactants

Gibbs free energy

change in energy that occurs during a chemical reaction, the energy difference between reactants and products

G products - G reactants

delta G =

exergonic

reaction that has negative Gibbs free energy change and is therefore spontaneous, energy is lost

endergenic

reaction that has positive Gibbs free energy change, energy is absorbed

-RTlnKeq

delta G = (in equilibrium)

enthalpy change (delta H)

measure of change in total bonding energy during a reaction, called a heat reaction, difference between bonds broken and formed

exothermic

A reaction that releases heat, delta H is negative

endothermic

A reaction that absorbs energy, delta H is positive

entropy change (delta S)

measure of the change in the amount of molecular randomness

decreases

when delta S is negative, randomness ---

increases

when delta S is positive, randomness ---

bond dissociation energy

energy required to break a bond to produce 2 radical fragments when the molecule is in the gas phase at 25 C, determined by the type of bond

intermediate

if a reaction occurs in more than 1 step, it must involve a species that is neither the reactant nor the final product this is called the --- step

Alkene

hydrocarbon containing C=C

dyes

many --- are alkenes, they also form olefin

ethylene, propylene

important sources of industrial chemicals and plastic products are --- and ---

unsaturated

alkenes that have fewer hydrogens than CnH2n+2

degree of unsaturation

number of multiple bonds or rings present in the molecule

saturated

acyclic compound CnH2n+2 is ---

organohalogens

family of chemicals that contain carbon and halogens (mainly Cl, F, I, and Br), when finding the degree of unsaturation convert halogens to hydrogens

Organoxygen

oxygen forms 2 bonds, can be ignored in the unsaturation calculation

Organonitrogen

nitrogen forms 3 bonds, you subtract one from hydrogen in unsaturation calculation

lowest

number the carbons in the chain so that the double bond has the --- possible number

diane

when there is more than one double bond in a ring, add --- to the end

sp2

carbons in a double bond are --- hybridized

differ

cis-trans isomerization requires end groups to --- in pairs

alkene stereochemistry

E-Z system is a method used for describing ---- ----

atomic, priority

Rule 1: Rank the substituent atoms according to the --- number of the first atom, higher --- number gets higher ---- (only 2 words)

connection

Rule 2: if atomic numbers are the same compare at new --- points a the same distance

equivalent

Rule 3: Multiple bonded atoms are --- to the same number of single bonded atoms

1

E-Z design should only have --- hydrogen attached to double bond

same

Z geometry: Molecules which have higher ranked groups on each carbon are on the --- side of the double bond

opposite

E geometry: molecules which have higher ranked groups are on --- sides

less

cis alkenes are --- stable than trans alkenes

heat

less stable isomers are higher in energy and give off more ---

hyperconjugation

electrons in neighboring filled s orbitals stabilize vacant antibonding p orbitals, net favorable interactions, stability of the alkene depends on the number of the --- that occurs

Markovnikov's Rule

hydrogen will add to the least substituted carbon of the double bond, halogens attach to the carbon with more alkyl substituents

unsymmetrical

in electrophilic addition reactions, --- substituted alkenes give a single product

regiospecific

Reaction in which only one of two possible orientations of an addition occur

intermediate

in the addition of HX to an alkene, more highly substituted carbocation forms as the --- rather than the less highly substituted one

Hammond Postulate

the structure of a transition state resembles the structure of the nearest stable species. transition states for endergonic steps structurally resemble products and transitions states for exergonic steps structurally resemble reactants

product

Hammond postulate: transition states for an endergonic reaction step structurally resembles the --- of that step

reactants

Hammond postulate: transition states for an exergonic reaction step structurally resembles the --- of that step

stable

faster reactions give more --- intermediates

lower

stability is reflected in the --- energy transition states

more

---- alkyl groups present, the lower energy

rearrangements

carbocations undergo structural --- during reactions of HX with an alkene

hydride shift

the shift of a hydrogen atom and its electron pair to a nearby carbon center