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Chemistry GRE Study
GRE study
298
Chemistry
Undergraduate 4
11/04/2012

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Term
mass number
Definition
total number of protons and neutrons in the nucleus, represented by the letter A
Term
atomic number
Definition
total number of protons in the nucleus, represented by the letter Z
Term
isotope
Definition
two or more nuclei of the same element that have different mass numbers
Term
binding energy
Definition
energy required to overcome proton-proton repulsion and hold the nucleus together
Term
parent nucleus
Definition
nucleus prior to nuclear decay
Term
daughter nucleus
Definition
nucleus formed as result of nuclear decay
Term
alpha decay
Definition
daughter has mass number 4 less than parent, atomic number 2 less than parent
Term
beta decay
Definition
daughter will always be a different element but will have the same mass number as parent
Term
gamma decay
Definition
daughter is identical to parent, except it has less energy
Term
first-order decay
Definition
probability that a nucleus will decay in a given time is constant and independent of the surrounding of the nucleus
Term
nuclear fission
Definition
when an accelerated particle such as a process when a neutron strikes a target nuclei, the nucleus can split into two or more fragments
Term
nuclear fusion
Definition
pricess when an accelerated particle is captured by a target nucleus to produce a larger nucleus
Term
radius of a nucleus
Definition
(1.33×10^(-13) )×∛A cm
Term
Bohr atom
Definition
an atom with only one electron
Term
energy shells
Definition
certain distances away from the nucleus
Term
number of electrons
Definition
2n^2
Term
ground state
Definition
configuration in which the electrons are in the lowest available energy levels
Term
excited state
Definition
configuration in which the electron is not in the lowest available energy level
Term
valence electrons
Definition
electrons with the largest value of n
Term
principle quantum number
Definition
n, energy level, ≥1
Term
secondary quantum number
Definition
l, angular momentum, 0-n
Term
degenerate
Definition
quantum states or configurations that have identical energies
Term
magnetic quantum number
Definition
m_l, -l to +l including 0
Term
s
Definition
1 orbital
Term
p
Definition
3 orbitals
Term
d
Definition
5 orbitals
Term
f
Definition
7 orbitals
Term
spin quantum number
Definition
m_s, +1/2 and -1/2
Term
Pauli exclusion principle
Definition
no two electrons in the same atom may ever have completely identical quantum numbers (n, l, m_l, m_s)
Term
Aufbau principle
Definition
to find the correct ground-state electron configuration of an atom, always completely fill all lower-energy orbitals before filling any higher-energy orbitals
Term
Hund's rule
Definition
when partially filling degenerate orbitals of p, d, and f subshells, always put one electron in each orbital before pairing them up. Also orient unpaired electrons so that their magnetic spins are all aligned in the same direction
Term
atomic size trend
Definition
increases as one moves down or the left in the periodic table
Term
atomic and ionic radii
Definition
cation < neutral atom < anion
Term
isoelectronic species
Definition
two atoms or ions that have the same number of electrons
Term
ionization
Definition
removal of an electron from a neutral atom
Term
endergonic process
Definition
requires input of energy
Term
first ionization energy
Definition
energy that is required to remove a single electron from an isolated gas-phase atom
Term
second ionization energy
Definition
energy required to remove a second electron from a gas-phase atom
Term
ionization energy
Definition
increases as one moves up or to the right of the periodic table
Term
electron affinity
Definition
amount of energy involved in adding a single electron to an isolated gas-phase atom, more negative as you move across a row or up a column
Term
exergonic
Definition
liberates energy
Term
electronegativity
Definition
ability of an atom in a molecule to polarize bonding electrons toward itself, increases as one moves up or to the right within the periodic table
Term
acidity
Definition
increases as one moves down or to the right in the periodic table
Term
basicity
Definition
increases as one moves up or to the left in the periodic table
Term
octet
Definition
the eight-electron arrangement in the outer electron shell of the noble-gas atoms
Term
cations
Definition
positively charged ion
Term
anions
Definition
negatively charged ion
Term
metalloid elements
Definition
elements that lie right along the delineation staircase line between metals and non metals
Term
Valence Shell Electron Pair Repulsion (VSEPR)
Definition
electron pairs, whether bonding or nonbonding, attempt to move as far apart as possible
Term
nonpolar bond
Definition
covalent bonds that are fatter at one end than at the other
Term
malleability
Definition
ability to be hammered into shapes
Term
ductility
Definition
ability to be drawn into sheets and wires
Term
band theory
Definition
metal is thought of as a giant molecule in which delocalized molecular orbitals cover the entire structure
Term
insulator
Definition
solid in which electrons saturate a band and a considerable gap exists between the completely filled band and the next available one
Term
semiconductor
Definition
has electrical properties that are intermediate between those of metals and insulators; electrical conductivity increases with incresing temperature
Term
intrinsic semiconductor
Definition
solid in which the band gap is so small that some electrons from the valence band will occupy energy levels in the conduction band
Term
extrinsic semiconductor
Definition
a substance that is normally an insulator can become semiconducting if small amount of other atoms are introduced intot the lattice, rendering it impure
Term
doping
Definition
introduction of an impurity
Term
n-type conductivity
Definition
charge carriers are negative electrons
Term
p-type conductivity
Definition
charge carriers are positive holes
Term
p-n junction
Definition
consists of a p-type semiconductor that's in close contact with an n-type semiconductor
Term
inversely polarized
Definition
if the p-zone is connected to the negative pole of a battery and the n-zone to the positive pole, the electrons are attracted to the (+) pole and the holes to the (-) pole, which is opposite to the normal direction of the displacement of electrons and holes at the juntion
Term
directly polarized
Definition
if the p-zone is connected to the positive pole, and the n-zone to the negative pole of the battery, the flow of electrons takes place in the normal direction at the junction
Term
coordinate covalent bonds
Definition
covalent bond that is formed between a transition metal ion and a polar molecule, formed by the donation of a pair of electrons from a polar molecule
Term
coordination complex
Definition
a molecule that consists of a transition metal ion bonded to polar molecules via coordinate covalent bonds
Term
Lewis base
Definition
a molecule that donates a pair of electrons to form a covalent bond
Term
Lewis acid
Definition
a molecule that accepts a pair of electrons to form a covalent bond
Term
intermolecular forces
Definition
forces that exists between two or more molecules
Term
intramolecular forces
Definition
forces that hold atoms together to form a molecule
Term
Coulomb's law
Definition
F=k (Q_1×Q_2)/R^2

F= force of electrostatic interaction, k= Coulomb's constant= 9.0×〖10〗^9 (Nm^2)/C^2 , Q_1=charge of particle #1 (in coulombs), Q_2= charge of particle #2, R= distance between the charges (m); if +, charges repel if - charges attract
Term
electron cloud repulsion
Definition
prevents atoms from passing right through one another, steric hindrance
Term
ionic bond
Definition
electrostatic attraction between two ions
Term
polar molecules
Definition
have a dipole moment, and an asymmetric distribution of electron density
Term
dipole forces
Definition
interactions between the charged portions of polar molecules
Term
hydrogen bond
Definition
a strong dipole-dipole interaction involving a H atom covalently bonded to a F, O,or N atom that is attracted to the partial negative charge of another F, O, or N atom
Term
London dispersion forces
Definition
arise from a momentary non-homogeneous distribution of electrons in an atom
Term
instantaneous dipole
Definition
when an atom has a slightly positive side and a slightly negative side
Term
dispersion force
Definition
the attraction between two adjacent, instantaneous, oppositely charged dipoles
Term
covalent compound
Definition
when the electronegativities of a compound's constituent elements differ by no more than about 1.5 units
Term
ionic compound
Definition
when the electronegativities of a compound's constituent elements differ by more than about 1.5 units
Term
crystal lattice
Definition
ions in an ionic compound are arranged in regular pattern
Term
unit cell
Definition
smallest unit that repeats itself indefinitely in three dimensions
Term
crystallorgraphy
Definition
branch of chemistry that studies the structure of unit cells
Term
cubic
Definition
cell edges: a=b=c, cell angles: α=β=γ=90°
Term
tetragonal
Definition
cell edges: a=b≠c, cell angles: α=β=γ=90°
Term
hexagonal
Definition
cell edges: a=b=c≠d, cell angles: α=β=γ=120°, edge d is perpendicular to the plane described by edges a, b, and c
Term
rhombohedral
Definition
cell edges: a=b=c, cell angles: α=β=γ≠90°
Term
orthorhombic
Definition
cell edges: a≠b≠c, cell angles: α=β=γ=90°
Term
monclinic
Definition
cell edges: a≠b≠c, cell angles: α=γ=90° β≠90°
Term
triclinic
Definition
cell edges: a≠b≠c, cell angles: α≠β≠γ
Term
ionic solids
Definition
made of + and - ions arranged in regular arrays; each ion is surrounded by ions of the opposite charge; hard, brittle, and have high melting and boiling points, poor conductors of electricity and heat
Term
covalent solids
Definition
made of atoms that are held together by very strong covalent bonds; very hard and have high melting points
Term
molecular solids
Definition
made of neutral molecules, held together by dipole forces or London dispersion forces; soft and are poor conductors of electricity and heat
Term
metallic solids
Definition
made of one closely packed metal element; very good electricity and heat conductors, can be soft or hard and have variable melting points
Term
close-packed structures
Definition
substance where atoms pack together as closely as possible
Term
tetrahedral hole
Definition
four spheres (3 in first layer, in triangular formation, and 1 above) create a regular tetrahedron about a void
Term
octahedral hole
Definition
hole bound by 6 spheres (3 in the first layer, in triangular formation, and 3 in the second layer, above, also in triangular formation, but offset by 60° with respect to the 3 spheres in the first row)
Term
triangular hole
Definition
hole between three adjacent speheres in the same layer
Term
coordination number (CN)
Definition
number of an atom's or ion's closest neighbors within the lattice
Term
cohesive energy
Definition
difference in energy between free ions and ionic solid
Term
lattice energy
Definition
sum of the energies of interaction of the ions in a crystal
Term
Madelung constant
Definition
the coulombic interaction can be evaluated theoretically using compressibility data, represents the effect on the ion of its neighboring ions
Term
Born-Haber cycle
Definition
calculation of the total energy of a crystal determined by considering all of its formation steps and including a lattice energy contribution
Term
K_eq
Definition
generic equilibrium constant
Term
dynamic equilibrium
Definition
individual molecules continue to react; however, there is no net change in the amount of reactants and products
Term
K_p
Definition
gaseous equilibrium constant
Term
K_a
Definition
acid equilibrium constant
Term
K_b
Definition
base equilibrium constant
Term
K_sp
Definition
dissolution equilibrium constant of ionic solutions
Term
Le Chatelier's Principle
Definition
chemical systems in dynamic equilibrium will remain in equilibrium indefinitely until acted upon by an outside influence
Term
reaction quotient (Q)
Definition
value that is obtained if nonequilibrium numbers are plugged into an equilibrium expression
Term
autoionization
Definition
spontaneous dissociation of water, reversible
Term
K_w
Definition
dissociation constant for water, 10^-14 M^2 at 25 C
Term
Arrhenius
Definition
acids produce H+ (aq); bases produce OH- (aq)
Term
Lowry-Bronsted
Definition
acids are proton donors; bases are proton acceptors
Term
amphoteric molecule/ion
Definition
can either donate or accept H+ (aq) in response to whatever else is in solution
Term
strong acid/base
Definition
completely dissociated acid/base
Term
strong acids
Definition
HCl, HBr, HI, HNO_3, H_2SO_4, HClO_4
Term
strong bases
Definition
group I hydroxides
Term
weak acid/base
Definition
acids/bases that partially, reversibly dissociate
Term
quadratic equation
Definition
(-b±〖(b^2-4ac)〗^(1/2))/2a
Term
conjugate pair
Definition
made up of two molecules that have identical molecular formulas, except that one of them has an additional H+, pk_a+pk_b=14 @ 25C
Term
conjugate rules
Definition
1. the conjugate acid of a strong base is neutral
2. the conjugate base of a strong acid is neutral
3. the conjugate acid of a weak base is an acid
4. the conjugate base of weak acid is a base
Term
buffers
Definition
minimize a change in pH when additional acid or base is introduced into solution, must consist of a conjugate pair of a weak acid and weak base
Term
Henderson-Hasselbalch equation
Definition
pH=pK_a+log⁡〖[A^- ]/[HA] 〗
Term
acid-base titration
Definition
used to determine:
1. the concentraion of an acid or base
2. whether an unknown acid or base is strong or weak
3. the pK_a of an unknown acid, or pK_b of unknown base
Term
titrant
Definition
known strong acid or base that is added to an unknown acid or base solution
Term
equivalence point
Definition
inflection or end point, point during a titration where just enough titrant (in moles) has been added to completely neutralize the subject acid or base
Term
half-equivalence point
Definition
the point at which enough titrant has been added to neutralize exactly one-half of the original unknown acid or base, point at which equal amounts of the unknown acid or base and its conjugate exist in the solution
Term
acid-base iindicator
Definition
the conjugate pair of a weak acid or base where each conjugate is a different color, change color at a pH+/-1 of their pK_a
Term
alkali metals
Definition
Group I, highly reducing, soft and silvery white, crystallize in the body-centered cubic crystal structure, salts soluble in water
Term
alkaline-earth metals
Definition
Group II, metallic in appearance, crystallize in close-packed, hexagonal close-packed structure, hexagonal and face-centered, face-centered and body-centered structure
Term
Group III
Definition
oxidation state +3
Term
Group IV
Definition
oxidation state +4
Term
Boron
Definition
forms simple trihalides, which are Lewis acids, undergo nucleophilic displacement reaction
Term
closoboranes
Definition
[B_nH_n]^-
Term
nidoboranes
Definition
B_nH_n+4
Term
arachnoboranes
Definition
B_nH_n+6
Term
saline carbides
Definition
largely ionic solids, formed by the elements of Groups I and II and by aluminum
Term
metallic carbides
Definition
formed by d and f block elements, electric conductors
Term
metalloid carbides
Definition
formed by boron and silicon and are covalent solids
Term
silicates
Definition
compounds that contain metals and the tetrahedral SiO_4^2- structure
Term
aluminosilicates
Definition
similar to silicates except that aluminum atoms replace some of the silicon atoms
Term
allotrope
Definition
different elemental forms
Term
halogens
Definition
Group VII, because of high reactivity, are only found as halides in nature, all nonmetals and diatomic
Term
rare gases
Definition
least reactive nonmetals
Term
interhalogens
Definition
compounds containing a halogen-halogen bond
Term
transition metals
Definition
elements found between Group II and III, recovered as ores or salts, have different oxidation states due to electrons being able to be lost from two different valence shells
Term
lanthanides
Definition
rare metals, oxidation state generally +3, properties are the result of partially filled f subshells
Term
actinides
Definition
radioactive elements
Term
ligands
Definition
coordination complexes formed with good Lewis bases
Term
monodentate
Definition
ligands that form a single coordination covalent bond
Term
chelates
Definition
ligands that form more than one bond
Term
molecular point groups
Definition
describe the geometry/symmetry of coordination complexes
Term
crystals field theory
Definition
model explaining how the presence of ligands can affect the electron configuration of a the metal atom
Term
18 electron rule
Definition
a way of gauging the relative stability of a complex

1. assign to the metal its number of valence s and outermost d electrons
2. for the ligands, assign electrons as per the following:
Ligand Electrons donated to M
H, CH3, CH2CH3, CN, OH, CI, NO 1
PR3, NH2, NH3, CO, RCN, ROOR’ 2
Cyclopentadinyl, indenyl 5
Benzene 6
Cyclooctatetraene 8

3.add up both contributions
4.when the organometallic complex has a charge, consider a + charge a - charge as an excess of electrons and add the corresponding number to the total

complexes that have 18 electrons counted tend to be more stable than ones that don't
Term
identity (E)
Definition
rotation about 360 degrees and yield the same, indistinguishable configuration
Term
center of symmetry (i)
Definition
a line that divides a molecule into two identical parts,such that every atom through i meets equivalent atoms at a distance equidistant from i
Term
rotation axis (C_n)
Definition
rotation about 360 degrees/n yields the same configuration
Term
mirror plane (σ)
Definition
reflection through a mirror plane yields the same configuration.
Term
rotation-reflection axis (S_n)
Definition
some molecules exist such that rotation about an axis, followed by a reflection through a plane perpendicular to the axis, yields the same configuration
Term
symmetry operations
Definition
when reflections are applied to a molecule and result in a representation that's indistinguishable from the starting configuration
Term
molecular point group
Definition
the group of all possible symmetry operations that can be performed on molecules of a given configuration
Term
Pt. Group: C_1
Definition
Element: E
Term
Pt. Group: C_2
Definition
E, C_2
Term
Pt. Group: C_2v
Definition
E, C_2, 2σ
Term
Pt. Group: D_2h
Definition
E, 3C_2, 3σ, i
Term
Pt. Group: D_3h
Definition
E, 2C_3, 3C_2, 4σ, 2S_3
Term
Pt. Group: D_4h
Definition
E, 2C_4, 5C_2, i, 2S_4, 5σ
Term
Pt. Group: T_d
tetrahedral
Definition
E, 3C_4, 8C_3, 6σ, 6S_4
Term
Pt. Group: O_h
octahedral
Definition
E, 8C_3, 6C_2, 6C_4, 3C_2, i, 6S_4, 8S_6, 9σ
Term
pairing energy
Definition
energy required to pair up the electrons
Term
high spin
Definition
when the strength of the crystal field interaction energy is less than the pairing energy
Term
low spin
Definition
when the crystal field interaction energy is greater than the pairing energy
Term
spin-only effective magnetic moment (μ_eff)
Definition
function of the number of unpaired electrons n, √(n(n+2)) in units of Bohr magnetons
Term
Jahn-Teller effect
Definition
octahedral and high-spin transition metal complexes often distort to lower symmetry to remove the electronic degeneracy
Term
formation of a complex
Definition
M^(n+)+ L →ML^(n+)

K_eq=([ML^(n+)])/([M^(n+) ][L])
Term
Irving-Williams series
Definition
K_eq increases from left to right

Ba^2+ < Sr^2+ < Ca^2+ < Mg^2+ < Mn^2+ < Fe^2+ < Co^2+ < Ni^2+ < Cu^2+ > Zn^2+
Term
spectrochemical series
Definition
provides an estimate of the ability of incoming ligands to cause the splitting of d orbitals

Br^- < Cl^- < SCN^- < F^- < OH^- < oxalate < H_2O < NH_3 < pyridine < NO_2^- < CN^- < CO
Term
ligand substitution
Definition
a coordinated ligand is replaced by another one
Term
redox reactions
Definition
electron transfer processes in which the oxidation state of the metal changes
Term
organometallic compound
Definition
a substance that contains at least one metal-carbon bond
Term
Grignard reagent
Definition
Mg + CH_3Br -> CH_3MgBr
Term
transmetallation
Definition
M + M'R -> MR + M', where M is a metal that is more electropositive than M'
Term
hydrometallation
Definition
MH + H_2C=CH_2 -> MH_2C-CH_3, in the case of unsymmetrical alkenes, the M group attaches to the less hindered carbon atom, and the smaller H attaches to the most hinder C
Term
hapticity (η)
Definition
describes organometallic compounds in the d and f groups, the number of atoms of a ligand that are attached to a metal atom
Term
toxic organometallic compounds
Definition
include organomercury, organotin, organolead, organoarsenic, and organosilicon compounds
Term
biomethylation
Definition
result of the reaction of methyl carbanions CH_3^- =, from naturally occurring biological agents such as cobalamin, CH_3CoB_12 + Hg^2+ -> CH_3Hg^+ + H_2OCoB_12^+
Term
catalysis
Definition
cyclic process, introduces new reaction mechanisms , which causes the catalyzed reaction to possess a lower Gibbs free energy of activation than a noncatalyzed reaction
Term
catalyst
Definition
a substance that increases the rate of a chemical reaction without being consumed
Term
homogenous catalysis
Definition
catalyst and reagents are present in the same phase
Term
heterogeneous catalysis
Definition
catalyst catalyst is present in a phase different from that of the reactants, most are solids that are easily separated from the products of the reaction
Term
turnover frequency (N)
Definition
the ration of the rate of the reaction (v) over the concentration of the catalyst([C] in homogenous catalysis) or the amount of catalyst (in heterogenous catalysis)
Term
solid-state chemistry
Definition
branch of chemistry concerned with the synthesis, structure, properties, and applications of solid materials
Term
defect structure
Definition
an important field of solid-state chemistry, defect of some sort greatly influence properties such as electrical conductivity, mechanical strength, corrosion, and chem reactivity
Term
point defects
Definition
defect at single site
Term
extended defects
Definition
defects that occur in 1, 2, or 3 dimensions
Term
intrinsic defects
Definition
defects that are present for strictly thermodynamic reasons, Gibbs free energy is usually lowered by the presence of defects
Term
Schottky defect
Definition
a point defect in which an ion is missing
Term
Frenkel defect
Definition
a point defect in which an atom or ion has been displaced to an interstitial site in the lattice
Term
extrinsic defects
Definition
defects that are not determined by thermodynamics and can be controlled by synthetic conditions and purification of the solid
Term
optical properties
Definition
ex: color change
Term
nonstoichiometric compounds
Definition
substances that have variable composition but constant basic structure, formula deviate from whole number ratios
Term
superconductors
Definition
important class of solids that possess the ability to conduct electricity without resistance
Term
bioinorganic chemistry
Definition
field of chemistry that studies the function of metals and nonmetals in biological processes
Term
cell membranes
Definition
membrane barrier that separates a cells interior and exterior
Term
carriers
Definition
alkali cations that carry molecules across the cell membrane
Term
calcium binding proteins
Definition
act a receptors for intracellular calcium and structural intermediates for enzyme catalysis
Term
enzyme
Definition
biological catalyst
Term
matalloenzyme
Definition
important class of enzymes characterized by the presence of a metal ion that is an essential participant in catalyzed reactions
Term
heme proteins
Definition
involved in electron transfer reactions, act as oxygen carriers, catalyze a variety of biochemical reactions
Term
heme
Definition
consists of folded, linked amino acid chains; a macrocyclic porphyrin ring that contains iron as its central metal and whose chemistry is influenced by ring substituents that differ from one type of protein to another
Term
sublimation
Definition
solid to gas phase
Term
ionization
Definition
release of an electron
Term
dissociation
Definition
diatomic to atomic
Term
electron affinity
Definition
addition of an electron (-)
Term
lattice energy
Definition
negative for ions coming together
Term
sublimation
Definition
solid to gas phase
Term
ionization
Definition
release of an electron
Term
dissociation
Definition
diatomic to atomic
Term
electron affinity
Definition
addition of an electron (-)
Term
lattice energy
Definition
negative for ions coming together
Term
organic chemistry
Definition
study of carbon, its compounds, and the reactions that they undergo
Term
international Union of Pure and Applied Chemistry (IUPAC)
Definition
regulates the systematic nomenclature of all compounds
Term
saturated hydrocarbon
Definition
acyclic, unbranched; univalent radicals
Term
enantiomers
Definition
nonsuperimposable, chiral mirror images
Term
diastereomers
Definition
stereoisomers that are not mirror images of each other
Term
S_N2 reaction
Definition
number 2 indicates both the nucleophile and the substrate are involved in the transition state, so process is biomolecular

bonds are broken heterolytically
Term
rate of S_N2 reaction for alkyl halides
Definition
consider steric hindrance, as the number of substituents increases, the transition state becomes increasingly crowded, and the rate of reaction decreases, order of increasing rate me > 1 > 2 > 3
Term
S_N1 mechanism for the substitution of alkyl halides
Definition
rate determining step is ionization of the tertiary or secondary halide to form a carbocation
Term
S_N1 reactivity
Definition
follows order of carbocation stability, order of increasing stability 3 > 2 > 1 > me
Term
E2 mechanism for substitution in alkyl halides
Definition
in transition state, the attacking base and the leaving group want to be as far apart as possible (anti positioning). this determines the stereochemistry

Saytzeff's rule applies: the more highly substituted alkenes are more stable than less substituted ones
Term
stability of alkenes
Definition
depends on the number of substituents on the double bond; most stable is most substituted
Term
Hofmann product
Definition
the less substituted alkene will predominate
Term
Diels-Alder reaction
Definition
occurs between a conjugated diene and a dienophile, product always contain 1 more ring than was present in the reactants, stereospecific
Term
nucleophilic aromatic substitutions
Definition
addition of a nucleophile and formation of a carbanion intermediate, followed by the loss of the halide ion

electron-withdrawing ortho- and para- substituents stabilize the carbanion intermediate more than meta- substituents

in the absence of electron-withdrawing substituents, this reaction is very rare and proceeds through a benzyne intermdiate
Term
Saytzeff's rule
Definition
when more than one beta carbon bears hydrogen atoms, it is the most substituted carbon that undergoes elimination
Term
Friedel-Crafts reaction
Definition
example of electrophilic aromatic substitution, in first step a carbocation is generated by reaction of the alkyl halide with aluminum trichloride, the second step is electrophilic attack on benzene to form alkylbenzene
Term
carbocation
Definition
a positive ion in which a positive charge resides on a carbon atom
Term
carbanion
Definition
formed after heteroltic cleavage of a bond between a carbon and a less electrnegative atom, resulting carbon has one additional electron, and it is therefore negatively charged
Term
free radical
Definition
generated by the absorption of light and subsequent homogenous bond dissociation

lack an octet of electrons and are exremely reactive as well as electrophilic
Term
carbene intermediate
Definition
neutral molecules of general formula R_2C: in which a carbon atom has two sigma bonds and two electrons
Term
stability of free radicals
Definition
methyl < primary < secondary < tertiary
Term
propagation step
Definition
in the presence of an alkane, the radical formed will break one of the C-H bonds, one electron remains on the alkane which becomes an alkyl radical and the other electron forms the bond inteh newly formed H-X molecule

the alkyl radical reacts with a halogen molecule to form the halogenated alkane
Term
Grignard reagent
Definition
RX + Mg -> RMgX
Term
synthesis f alkanes
Definition
1. reduction of alkyl halides
2.catalyzed hydrogenation of alkenes and alkynes to produce alkanes
3. Corey-House synthesis
Term
Corey-House synthesis
Definition
(a) 2R-Li +CuI -> (under dry ether) R_2CuLi +Li
(b) R_2CuLi + R'-X -> R'-R + RCu +LiX
Term
Major reaction of alkanes
Definition
1. thermal dehydrogenation (cracking)
2.combustion
3. halogenation
Term
polymerization
Definition
produces polymers which are large molecules made of chain-linked starting molecules called monomers or mers
Term
synthesis of alkenes
Definition
1. dehydrogenation of alkanes
2. dehydration of alcohols (ROH
3. dehyrohalogenation of alyl halides (RX)
4. dehalogenation of vicinal dihalides
5. reduction of alkynes (RC-Cr)
Term
reactions of alkenes
Definition
1. addition of hydrogen halides (HX) across double bonds (Markovnikov addition)
2. hydration of alkenes to produce alcohols (Markovnikov addition)
3. addition of H_2SO_4 to alkenes to produce alcohols (Markovnikov addition)
4. oxymercuration-demercuration of alkenes to produce alcohols
5. catalytic hydrogenation of alkene to produce alkanes
6. cyclopropanation
7. allylic substitution
8. ozonolysis of alkenes to produce carbonyl groups
Term
Markovnikov's rule
Definition
addition of a proton to the double bond of an alkene yields a product in which the proton is bonded to the carbon atom that already bears the greater number of hydrogens
Term
preparation of alkynes
Definition
1. dehyrohalogenation of dihalides
2. alkyl substitution
Term
vic-dihalides
Definition
halogens on adjacent carbons
Term
gem-dihalide
Definition
halogen atoms are bound to the same carbon
Term
diene
Definition
alkene that has two C=C bonds in the formula
Term
conjugated
Definition
double bonds that are separated by only one single bond, more stable than isolated bonds
Term
isolated
Definition
double bonds that are separated by more than one single bond
Term
synthesis of dienes
Definition
1. dehydration of diols
2. dehydrogenation of alkenes
3. dehydrohalogenation of dihalides
Term
reactions of dienes
Definition
1. addition of hydrogen
2. Diels-Alder reaction
Term
use of grignard reagents
Definition
1. formaldehyde to primary alcohol
2. aldehyde to secondary alcohol
3. ketone to tertiary alcohol
4. nitrile to ketone
5. carbon dioxide to carboxylic acid
Term
primary alcohol
Definition
-OH group bound to a carbon that's directly bound to only one other carbon
Term
secondary alcohol
Definition
-OH group bound to a carbon that's directly bonded to only two other C atoms
Term
tertiary alcohol
Definition
-OH group bound to a carbon that's directly bonded to three other C atoms
Term
alkoxide ion
Definition
RO-

produced when a proton of alcohol is removed by a strong base
Term
reactions of alcohols
Definition
1. oxidation of primary alcohols to carboxylic acids
2. oxidation of primary alcohols to aldehyde
3. oxidation of secondary alcohols to ketones
4. reduction of alcohols to alkanes
5. synthesis of alkyl halides
6. dehydration to alkenes
7. dehydration to ethers
8. tosylation
9. acylation
10. deprotonation to alkoxide
Term
thiols
Definition
-SH (sulfhydryl) functional group bound to a carbon
Term
synthesis of esters
Definition
1. Williamson synthesis
2. intermolecular dehydration
Term
benzyne
Definition
compounds that are forded as reactive intermediates in the reaction of alkyl halides with strong bases
Term
enols
Definition
compounds that exist as an equilibrium mixture of ketone and alcohol tautomers
Term
organometallic compound
Definition
consists of a carbon atom covalently bonded to a metal
Term
carbohydrates
Definition
C_n(H_2O)_m, synthesized by almost all living organisms as a source of metabolic energy
Term
monosaccharides
Definition
saccharides that cannot be hydrolyzed to simpler structures
Term
disaccharide
Definition
can be hydrolyzed to yield two monosaccharides
Term
aldoses
Definition
contain the aldehyde functional group
Term
ketoses
Definition
contain the ketone group
Term
epimer
Definition
compounds whose stereochemistry differs at only one carbon
Term
polysaccharides
Definition
consist of several monosaccharides linked by glycosidic bonds
Term
oligosaccharides
Definition
contain up to ten monosaccharides
Term
ribonucleosides
Definition
building blocks of nucleic acids

glycosides of ribofuranose
Term
isoelectric point
Definition
the pH at which the amino acid exists as an equilibrium mixture of anionic and cationic forms
Term
dalton
Definition
unit of mass equal to the mass of one hydrogen atom
Term
simple proteins
Definition
polypeptide assemblies that hydrolyze to their constituent amino acid residues
Term
conjugated proteins
Definition
incorporate groups such as carbohydrates, lipids, nucleic acids, and various prosthetic groups
Term
prosthetic group
Definition
active groups

often the site of the main biochemical activity of the protein
Term
primary structure of proteins
Definition
covalent assembly

amino acid sequence and the presence of disulfide bridges
Term
secondary structure of proteins
Definition
arragnements adopted by the amino acid sequence

alpha-helix, beta-pleted sheet, random coil

can coexists in the same protein
Term
alpha-helix
Definition
a polypedtide arrangement in which the carbonyl groups on one turn of the helix hydrogen bond to the hydrogens of the peptide N-H bond of the next turn
Term
beta-pleated sheet
Definition
a polypeptide arrangement in which the chains line up side by side with the carbonyl groups of one chain hydrogen bonded to the hydrogens of the N-H bond of the adjacent chain
Term
random coil
Definition
any nonhelical or nonpleated sheet polypeptide arrangement
Term
tertiary structure of proteins
Definition
the complete three-dimensional conformation of the protein and the folding pattern of its secondary structure
Term
quaternary structure of proteins
Definition
the "sum total" of the protein assembly, including complexations with ligands, inhibitors, etc
Term
physical chemistry
Definition
the study of changes is the study of changes in energy and entropy and the rate of change of nonequilibrated systems
Term
thermodynamics
Definition
study of transformations of various kinds of energies and the exchange of energy between systems and their surroundings
Term
system
Definition
any part of the universe, any object, and any quality of matter
Term
state properties
Definition
measurable variables
Term
surroundings
Definition
includes everything around the system
Term
boundary
Definition
encloses a system, setting it apart from its surroundings

imaginary construct which serves either to (a) completely isolate the system from its surroundings or (b) allow interactions between the system and its surroundings
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