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CHEM251 Exam 1
Loudon Ch. 1-3
128
Organic Chemistry
Undergraduate 2
09/18/2011

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Cards

Term
aliphatic hydrocarbons
Definition
hydrocarbons containing carbon and hydrogen joined together in straight chains, branched trains or non-aromatic rings
Term
alkanes (paraffins)
Definition
hydrocarbons that contain only single bonds
Term
alkenes (olefins)
Definition
hydrocarbons that contain carbon-carbon double bonds
Term
alykyl groups
Definition
substiuents derived from alkanes
Term
alkynes (acetylenes)
Definition
hydrocarbons that contain carbon-carbon triple bonds
Term
amphoteric compounds
Definition
compound that can act as either an acid or a base
Term
angular momentum quantum number
Definition
s, p, d, f orbitals and so on (=principal qn -1)
Term
anti
Definition
conformation in which the dihedral angle is 180
Term
anti bonds
Definition
two bonds that have a dihedral relationship of 180
Term
antibonding molecular orbital
Definition
a region in which the wave is zero; electrons in [] decreaase bonding becae the region between the nuclei contains no electron density
Term
atomic orbital
Definition
description of the wave properties of an electron in an atom; the allowed state of an electron
Term
aufbau principle
Definition
electrons are placed one by one into orbitals of lowest energy in a manner consistent with the Pauli exclusion principle and Hund's rule
Term
boiling point
Definition
temperature at which the vapor pressure of a substance equals atompheric pressure
Term
bond angle
Definition
the angle between each pair of bonds to the same atom
Term
bond dipole
Definition
a polar bond's associated dipole moment contribution
Term
bond dissociation energy
Definition
direct measure of bond strength
Term
bond length
Definition
distance between centers of the bonded nuclei
Term
bond order
Definition
describes the number of covalent bonds shared by two atoms
Term
bonding molecular orbital
Definition
continuous orbital that includes the region between the two nuclei; electrons in [] are attracted to both cuclei simultaneously
Term
Bronsted acid
Definition
species that donates a proton in a chemical reaction
Term
Bronsted acid-base reaction
Definition
electron-pair displacement reaction on a hydrogen
Term
Bronsted base
Definition
species that accepts a proton in a chemical reaction
Term
combustion
Definition
rapid reaction with oxygen to give carbon dioxide and water, initiated by a suitable heat source
Term
compound class
Definition
compounds that contain the same functional group
Term
condensed structural fomula
Definition
simpler structural representation of a molecule in which it is assumed that the hydrogens are connected
Term
conformation
Definition
the spatial arrangement of its atoms when all of its dihedral angles are specified
Term
conformational analysis
Definition
investigation of molecular conformations and their relative energies
Term
conjugate acid
Definition
formed when a Bronsted base gains a proton
Term
conjugate acid-base pair
Definition
results when a Bronsted acid loses a proton or Bronsted base gains a proton
Term
conjugate base
Definition
results when a Bronsted acid loses a proton
Term
connectivity
Definition
order in which an molecule's atoms are connected
Term
constitutional isomers (structural isomers)
Definition
isomers taht differ in the connectivity of their atoms
Term
covalent bond
Definition
nonionic compound which consists of an electron pair that is shared between bonded atoms
Term
curved-arrow notation
Definition
symbolic device for keeping track of electron pairs in chemical reactions; "flow" of electrons from the electron donor to the electron acceptor
Term
cylindrical symmetry
Definition
no matter how the molcule turns about a line joing two nuclei, its electron density looks the same
Term
dihedral angle (torsion angle)
Definition
angle between two planes of a molecule
Term
dipole moment
Definition
unevent electron distiburtion in a comound containing covalent bonds
Term
double bond
Definition
bond consisting of two electron pairs
Term
eclipsed conformation
Definition
the groups along a Newman projection are superimposed
Term
electron affinity
Definition
energye required to transfer an electron to a bonded atom in the breaking of that bond
Term
electron spin
Definition
the magnetic property of the elctron; only two values possible (up +1/2 or down -1/2); fourth quantum number
Term
electron-deficient compounds
Definition
atoms that are short of an octet by one or more electron pairs
Term
electron-donating effect
Definition
groups that do NOT pull electrons toward themselves and away from the carbon to which they are attached
Term
electronegative
Definition
the more an tom attracts elctrons, more [] it is
Term
electronegativity
Definition
tendency of an atom to attract electrons to itself in a covalent bond
Term
electronic configuration
Definition
the way an atom's electrons are distributed among their atomic orbitals
Term
electron-pair displacement reaction
Definition
reaction in which one electron pair is displaced from an atom by the donation of another elctron pair from another atom
Term
electron-withdrawing polar effect
Definition
polar effect of halogens and other elctronegative groups; they pull electrons toward themselves and away from the carbon to which they are attached
Term
electrophile
Definition
atom that receives a pair of electrons from the Lewis base
Term
electrostatic attraction
Definition
stabilizing interaction between opposite charges
Term
electrostatic potential map
Definition
illustrates the charge distributions of molecules three dimensionally
Term
element effect
Definition
effect of changing the directly attached atom (A) on the acidity of H-A
Term
formal charge
Definition
assigned charge on each atom
Term
fractional distillation
Definition
mixture of compounds is slowly boiled; the vapor is collected, cooled, and recondensed to a liquid
Term
functional group
Definition
characteristically bonded group of atoms that has about the same chemical reactivity whenever it occurs in a variety of compounds
Term
gauche bonds
Definition
two bonds with dihedral relationship of 60
Term
gauche
Definition
conformation with dihedral angles of 60 and 300
Term
Heisenberg uncertainty principle
Definition
the accuracy with which we can determine the position and velocity of a particle is inherently limited
Term
Homologous series
Definition
series of compounds that fdiffere by the addition of methylene groups
Term
Hund's rule
Definition
first, to distribute electrons among identical orbitals of equal energy, single elctrons are placed into separate orbitals before the orbitals are filled; second, the spins of these unpaired elctrons are the same
Term
hybrid orbitals
Definition
new orbitals formed by hybridization
Term
hybridization
Definition
process in which atomic orbitals convert to molecular orbitals
Term
induced dipole
Definition
when a second molecules is located nearby, its electron cloud distorts  to form a complementary dipole
Term
internal rotation
Definition
one conformation converting to another relative to others about the carbon-carbon bond
Term
ionic bond
Definition
electrostatic attraction that holds ions together
Term
ionic compound
Definition
chemical compound in whitch the component atoms exist as ions
Term
ionization potential
Definition
energy required for the loss of an electron from the bonded atom
Term
isomers (isomeric compounds)
Definition
different compounds that have the same molecular formula
Term
isobutyl
Definition
(CH3)2CHCH2-
Term
isopropyl
Definition
(CH3)2CH-
Term
leaving group
Definition
one of its atoms accepts an electron pair from a break bond (takes a pair of bonding elctrons and runs)
Term
Lewis acid
Definition
species that accepts an electron pair to form a new bond in a chemical reaction
Term
Lewis acid-base association
Definition

electron-deficient Lewis acid and a Lewis base combine to give a single product

Term
Lewis base
Definition
species that donates the electron paire to a Lewis acid to form a new bond
Term
Lewis strucutures
Definition
molecular structures that use the Lewis dot notation for the electron pair bond
Term
linear
Definition
molecular geometry for an atom with two surrounding groups (angle = 180)
Term
magnetic quantum number
Definition
(=+/- angular momentum qn)
Term
melting point
Definition
the temperature at which a substance is transformed spontaneously and completely from the solid to liquid state
Term
methylene group
Definition
-CH2-
Term
molecular formula
Definition
gives its atomic composition
Term
molecular geometry
Definition
specification of how far apart the atoms are and how they are situated in space
Term
molecular models
Definition
commercially available scale models from which you can construct simple organic molecules
Term
molecular orbitals (MO)
Definition
orbitals for the entire molecule
Term
neopentyl
Definition
(CH3)3CCH2-
Term
Newman projection
Definition
type of planar projection along one bond
Term
node
Definition
point, or a surface in 3D, at which the wave is zero
Term
normal alkanes (n-alkanes)
Definition
alkanes with unbranched carbon chains
Term
nulceophile
Definition
Lewis base that donates an electron pair to an atom otehr than hydrogen
Term
octet rule (ionic)
Definition
tendency of atoms to gain or lose valence electrons to form ions with noble-gas configuartion
Term
orbital interaction diagram
Definition
plot of orbital energy versus the postion of the two interacting nuclei
Term
organic chemistry
Definition
branch of science that deals generally with compounds of carbon
Term
Pauli exclusion principle
Definition
no two electrons may have all four quantum numbers the same
Term
petroleum
Definition
crude oil
Term
polar bond
Definition
bond in which electrons are shared unevenly
Term
polar effect (inductive effect)
Definition
effect on chemical properties caused by the interaction between charges, dipols, or both
Term
polar molecules
Definition
molecules that have permanent dipole moments
Term
principal chain
Definition
longest continuous carbon chain in the molecule
Term
principal quantum number
Definition
number associated with the valence shell (counted out from the nuclei in increasing energy)
Term
quantum number
Definition
in the mathematics of "electron waves" each orbital has an []
Term
resonance hybrid
Definition
representation of a molecule using several structures to demonstrate the "true" form
Term
sec-butyl
Definition
(CH3CH2CH)-|CH3
Term
sigma bond
Definition
bonds in which the electron density is cylindrically symmetrical about the internuclear axis
Term
skeletal strucutures
Definition
structure-drawing convention that only shows the carbon-carbon bonds
Term
staggered conformation
Definition
bond of one group bisects the angle between two other groups down a Newman projection
Term
standard free energy of dissociation
Definition
deltaG = -RTln(Ka) = -2.3RTlog(Ka)
Term
structural formula
Definition
a molecule's Lewis structure, which shows its connectivity of its atoms
Term
structure
Definition
know [] of a molecule when we know its atomic connectivity and molecular geometry
Term
substituents
Definition
branching groups on hydrocarbons
Term
substitutive nomenclature
Definition
mostly widely applied nomenclature system in use today
Term
tert-butyl
Definition
(CH3)3C-
Term
tetrahedron
Definition
3D object with four triangular faces (angle = 109.5)
Term
total electron density
Definition
probability of finding electrons in the region of a molecule
Term
trigonal planar
Definition
molcular geometry for an atom with three surrounding groups (angle =120)
Term
trigonal pyramidal
Definition
molecular geometry for an atom with three surrounding groups and an unshared pair
Term
triple bond
Definition
bond involving three electron pairs
Term
unshared pairs
Definition
unshared valence electrons in Lewis structures are depicted as paired dots
Term
valence electrons
Definition
electrons in the outer most shell of an atom
Term
valence orbitals
Definition
the orbitals of an atom that contain the valence electrons
Term
valence shell
Definition
outermost shell of electrons in an atom
Term
van der Waals attractin (dispersion interaction)
Definition
attraction between temporary dipoles
Term
van der Waals radius
Definition
measure of an atom's effective size
Term
van der Waals replusion
Definition
extra energy required to force two nonbonded atoms within the sum of their van der Waals radii
Term
VSEPR theory
Definition
bonds and electrons are arranged about a central atom so that the bonds are as far apart as possible
Term
wavefunction
Definition
atomic orbital described in physics by this mathematical function
Term
octet rule (covalent)
Definition
sum of all shared and unshared valence electrons around each atom in many stable covalent compounds is eight (two for the hydrogen atom)
Term
electropositive
Definition
the less an atom attracts electrons, the more [] it is
Term
torsional strain
Definition
repulsion between electrons in bonds that effects the energy of conformations and effects the bond angles of molecules
Term
Lewis acid-base dissociation
Definition

single molecule reacts to form a Lewis acid and Lewis base; reverse of Lewis acid-base association

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