Chemistry
General Chemistry Organic Chemistry Physical Chemistry
General Chemistry
Terms
Chemical Formulas and Composition Stoichiometry
Allotropes - different forms of element in same physical state, eg O2 and O3
Law of Definite Proportions - compound always has ratio of elements same by mass
Law of Multiple Proportions - ratio of masses of elements in compound is small whole number ratio Stoichiometry - quantitative relationships, composition or reaction
Chemical Equations and Reaction Stoichiometry
Law of Conservation of Matter - matter is not created or destroyed, only rearranged Limiting reactant - the reactant that is used up completely in the reaction
Solution - solute dissolved in solvent
Titration - titrant reactant slowly added to solution of another reactant and measure amount for complete reaction; plot curve of added volume vs. pH; at equivalence point equal amounts of acid and base reacted, should coincide with end point, when indicator color changes; use buret
Types of Chemical Reactions
Periodic Law - properties of elements are periodic functions of atomic number
Metals - high conductivity (inc. with inc. temp.), high thermal conductivity, solid except mercury (Ce and Ga melt), malleable, gray except Ag and Au, few electrons in outer shell, metallic character inc.
down and left on PT
Electrolytes - substances whose aqueous solutions conduct electricity well, incl. strong acids, strong soluble bases, most soluble salts
Precipitates - settle out of solution
Oxidation number - number of electrons gained or lost by atom in binary compound Oxidation - loss of electrons
Reduction - gain of electrons Oxoacids - ternary acids The Structure of Atoms
Photoelectric effect - electromagnetic radiation causes electron emission from metal surface Heisenberg Uncertainty Principle - can't know both momentum and position of small particle Aufbau Principle - electrons added into orbitals in way giving lowest total energy
Pauli Exclusion Principle - no two electrons in atom have same 4 quantum numbers Hund's Rule - electrons mus toccupy all orbitals of a sublevel before pairing Paramagnetic - unpaired electrons weakly attracted into magnetic fields
Diamagnetic - all electrons paired and are very weakly repelled by magnetic fields Ferromagnetic - Fe, Co, and Ni permanently magnetized as spins align with field Chemical Periodicity
Screening causes effective nuclear charge to be less than actual nuclear charge
Combustion reaction - oxygen combines rapidly, very exothermic, hydrocarbon+oxygen yields carbon dioxide water and heat
Roasting - extracting free metals by heating an ore in air (oxygen)
Chemical Bonding
Ionic compounds - high melting pt., soluble in polar solvents, insoluble in nonpolars, molten and aqueous solutions conduct electricity; large electronegativity difference between atoms
Lewis dot formulas - show valence electrons
Octet Rule - most compounds achieve noble gas configurations Resonance - two or more Lewis structures describe bonding Formal charge - charge on atom in a molecule or polyatomic ion Molecular Structure and Covalent Bonding
Polar covalent bond - electrons shared unequally; creates dipole Sigma bond - head on overlap; all single bonds are sigma Pi bond - side on overlap; may include unhybridized p orbital Molecular Orbitals
Molecular orbital - an orbital resulting from overlap and mixing of atomic orbitals on different atoms;
belongs to molecule as whole
Antibonding orbital - molecular orbital higher in energy than any of atomic orbitals from which it is derived; lends stability when populated; marked with asterick
Nonbonding orbital - orbital derived only from an atomic orbital of one atom; lends no stability Delocalization - formation of set of molecular orbits that extend over more than two atoms Nodal plane - region of zero probability of finding electrons
Acids, Bases, and Salts
Protonic acids - acids with acidic hydrogen atoms
Arrhenius theory - acid produces H+ in aqueous solution; base produces OH- in solution Bronsted-Lowry theory - acid is proton donor; base is proton acceptor
Lewis theory - acid accepts a share in electron pair, base donates a share in electron pair
Conjugate acid-base pairs - differ by proton; weak acid yields strong conjugate base and vice versa Amphoterism - ability to react as either acid or base
Coordinate covalent bond - both electrons furnished by one atom
Standardization - process to determine concentration by measuring volume required to react with known amount of primary standard
Equivalent weight of an acid - mass needed to furnish 6.022*1023 hydrogen ions Half-reaction - either reduction or oxidation part of redox reaction
Gases
Fluids - liquids and gases; flow freely
Vapor - gas formed by evaporation or sublimation
Pressure - force per unit area; measured by barometer (1 torr = 1 mm Hg), manometer U-shaped tube Dumas method - used to find molecular weights of volatile liquids using boiling water bath
Kinetic-molecular theory - by Rudolf Clausius; collisions are elastic, molecules travel in straight line with constant velocity until collide; gases consist of discrete molecules
Effusion - escape of gas through tiny hole
Diffusion - movement of gas into a space or mixing with another gas
London forces - weak attractive forces in molecules; vary as 1/d7; only intermolecular forces among symmetric nonpolars
Dipole-dipole interactions - attraction of opposite partial charges; vary as 1/d4 Hydrogen bonding - H to F, O, or N; like dipoles
Liquids and Solids
Viscosity - resistance to flow of a liquid; can measure with Ostwald viscometer Surface tension - inward force overcome to expand surface are of liquid Meniscus - surface of liquid
Cohesive forces - hold liquid together; adhesive forces hold liquid to another surface Evaporation - opposite of condensation; molar heat of vaporization and heat of condensation
Vapor pressure - partial pressure of vapor molecules above liquid surface; easily vaporized are volatile Boiling point - vapor pressure = external pressure
Melting - opposite of freezing; molar heat of fusion and heat of solidification Sublimation - opposite of deposition
Phase diagrams - temperature vs. pressure; triple point all 3 states at equil. (4.6 torr, 0.01 C for water);
can't liquefy gas above critical point
Amorphous solids - no well-defined structure (like rubber, some plastics)
Crystals - unit cells repeat and can be replaced with lattice point; 7 systems incl. Cubic, tetragonal, orthorhombic, monoclinic, triclinic, hexagonal, rhombohedral
Isomorphous - substances that crystallize in same type of lattice Polymorphous - substance that crystallizes in multiple forms Coordination number - number of neighbors in solid packing
Metallic bonding - band theory describes continuous bands of closely spaced molecular orbitals Conduction band - a band electrons must move into to allow conduction; insulators have band gap;
semiconductors have filled bands that are slightly below empty bands Solutions
Solvation - process of solvent molecules surrounding solute ions or molecules; called hydration if water Miscibility - ability of a liquid to dissolve in another; add acid to water
Saturated - solid and dissolved ions in equilibrium
Supersaturated - high solute prepared at high temperature then cooled
Colligative properties - physical properties depending on number not kind of solute particles Fractional distillation - separate liquid mixture by boiling points
Boiling point diagram - mole fraction vs. temperature; bowed curves for vapor and liquid; intercepts show boiling points
Colloids - dispersed phase (solutes) suspended in dispersing medium (solvent); solid in solid solid sol, liquid in solid solid emulsion, gas in solid solid foam, solid in liquid sols and gels, liquid in liquid emulsion,
gas in liquid foam, solid in gas solid aerosol, liquid in gas liquid aerosol Tyndall effect - scattering of light by collodial particles
Micelles - cluster of molecules with hydrophobic tails in center and hydrophilic heads outward Surfactant - has ability to suspend and wash away oil and grease
Hard water - contains Fe3+, Ca2+, and/or Mg2+ ions
Emulsifiers - coat particles of dispersed phase to prevent coagulation into separate phase Synthetic detergents - soap-like emulsifiers with sulfonate or sulfate instead of carboxylate Eutrophication - overgrowth of vegetation because of high phosphorous concentration Thermodynamics
State function - value depends only on current state not how it got there
Calorimetry - measuring heat transfer between system and surroundings using calorimeter; coffee-cup and bomb caliometers (constant volume)
Enthalpy - heat content
Standard molar enthalpy of formation - enthalpy change for reaction in which one mole is formed from its elements at their standard states
Bond energy - energy needed to break one mole of bonds Kinetics
Transition state theory - activation energy to form transition state
Mechanism - step by step reactions; rate determined by slowest, rate-determining step
Heterogeneous catalysts - speed up reaction but are in different phase than reactants, such as powdered noble metals and metal oxides in catalytic converters
Enzymes - biological catalysts; bind substrates Equilibrium
Chemical equilibrium - two opposing reactions occur simultaneously at same rate; dynamic equilibrium LeChatelier's Principle - system responds to stress at equilibrium in a way that reduces stress and reaches
new state of equilibrium Haber process - N2 + 3H2 <-> 2NH3
Acids and Bases
Common ion effect - behavior of solution in which same ion is produced by two different compounds Buffers - minimize changes in pH because basic component can react with H3O+ ions and acidic
component can react with OH- ions
Polyprotic acids - furnish two or more hydronium ions per mole
Solvolysis - reaction of substance with the solvent in which it is dissolved; hyrolysis if water Solubility Product Principle
Solubility product constant Ksp - equilibrium constant for reactions involving slightly soluble compounds Solubility Product Principle - like equilibrium expression, but can take solids to be one
Fractional precipitation - remove some ions from solutions while leaving others in
Molar solubility - number of moles of solute that dissolve to produce liter of saturated solution Electrochemistry
Electrolytic cells - external electricity causes nonspontaneous reactions by electrolysis Voltaic cells (galvanic cells) - spontaneous chemical reactions produce electricity
Electrodes - surfaces upon which oxidation (anode) or reduction (cathode) half reaction occurs Downs Cell - electrolysis of molten sodium chloride
Faraday's Law of Electrolysis - amount that oxidizes or reduces at each electrode is directly prop. to amount of electricity that passes through cell
Faraday - amount of electricity that reduces one equivalent weight at cathode and reduces at anode Electroplating - using using electrolysis to plate metal onto surface
Salt bridge - circuit between two solutions in a voltaic cell
Standard cell - all species are in thermodynamic standard states (1 M , 1 atm)
Standard Hydrogen Electrode (SHE) - reference electrode relative to which electric potentials are measured as reduction at 25 C; if Eo > 0 reduction occurs more readily than 2H+ to H2
Corrosion - redox process by which metals are oxidized by oxygen in presence of moisture; prevent by plating or galvanizing (coating steel with zinc)
Primary voltaic cells - cannot be recharged; includes Georges Leclanche's dry cell (ZN(NH4)3) and alkaline dry cells
Secondary voltaic cells - reversible; can be recharged, such as lead storage battery in cars (PbSO4), nickel- cadmium (nicad) cells, and hydrogen-oxygen fuel cells
Metallurgy
Native ores - uncombined free state of less active metals, like Cu, Ag, Au Ores - contain minerals mixed with gangue (sand, rock, etc)
Metal separation includes flotation, roasting (heating with oxygen), reaction with coke (carbon) or CO, and electolysis of molten salt
Hall-Heroult process - cell for electolyzing Al
Iron - blast furnace with CO converts to limestone flux, which reacts with silica gangue to form slag of
calcium silicate; iron from blast furnace contains carbon (pig iron); remelted and cooled to cast iron; add other metals like Mn, Cr, Ni, W, Mo, V to make steel
Coordination Compounds
Coordination compounds - compouns with bonds in which both shared electrons are donated by same atom Ligand - a Lewis base in a coordination compound
Polydentate - ligands with multiple donor atoms
Chelate - a ligand that utilizes two or more donor atoms in bonding to metals Nuclear Chemistry
Nuclear fission - splitting of heavy nucleus into lighter nuclei
Nuclear fusion - combination of light nuclei to produce heavier nucleus
Mass deficiency - difference between sum of masses of electrons/proton/neutrons and actual mass
Scintillation counter - detects radiation using fluorescence
Cloud chamber - detects radiation using water vapor; developed by Wilson Gas Ionization chamber - such as Geiger-Muller counter
Disintegration series - sequence of atoms during decay Radiocarbon dating - C14, K-Ar, U-Pb methods
Radioactive tracers - Na24 blood, Th201 and Tc99 heart, I131 thyroid liver and brain, Pl238 pacemakers Cyclotrons - devise for accelerating charged particles along spiral path
Linear accelerators - device used for accelerating charged particles along straight line path Uranium-235 decay - to Uranium-236 to Sm/Zn, La/Br, Ba/Kr, Cs/Rb, Xe/Sr
Fission reactors - use U3O8 fuel rods enriched in uranium-235, water and graphite moderators (and He and heavy water), B/Li control rods, cooling systems, concrete shielding
Thermonuclear bombs (fusion bombs, hydrogen bombs) - activation energy of fusion obtained by fission Plasma - state of matter at high temperatures at which all molecules are dissociated and most ionized
Equations
D=m/V
Sp. Gr. = D/Dwater
Sp. Heat = (heat in J)/((mass in g)*(temp. change in C)) Molarity = moles/Liter
V1M1 = V2M2
v = f
E = hv
Rydberg equation: 1/ = R(1/n12-1/n22) relating H spectrum wavelengths
De Broglie equation: = h/(m*f) showing small particles can display wave properties
Schrodinger's equation: in terms of electron wave function , solutions are possible energy states for electron in atom; Dirac incorporated relativity
Number of atomic orbits = (energy level n)2
Formal charge = (group number) - (number of bonds) - (number of unshared electrons) Dipole moment = (distance)*(magnitude of charge)
Bond order = (bonding electrons - antibonding electrons)/2
Normality = (number of equivalent weights of solute)/(L of solution) Boyle's Law : P1V1 = P2V2 ; volume inversely prop. to pressure Charles' Law: V1/T1 = V2/T2 ; volume directly prop. to temperature Combined gas law : P1V1/T1 = P2V2/T2
Avogadro's Law: V1/n1 = V2/n2 ; volume directly prop. to number of moles of gas Ideal Gas Law: PV = nRT
Dalton's Law of Partial Pressures: Ptotal = PA + PB + PC + ... ; partial pressure of each gas is its mole fraction times total pressure of mixture
Average molecular kinetic energy is directly prop. to absolute temperature
Van der Waals equation: (P+n2a/V2)(V-nb) = nRT ; extends ideal gas law to real gases using two empiricals Coulomb's Law: F=kq1q2/d2
Clausius-Clapeyron equation: relates temperature to vapor pressure and molar heat of vaporization Bragg equation: n = 2*d*sin(), relates reflections for X-rays to wavelength and distance
Henry's Law: Pgas = kCgas ; pressure of gas above solution is prop. to concentration of gas in solution Molality = (number of moles of solute)/(number of kilograms of solvent)
Raoult's Law: Psolvent = Xsolvent/P0solvent ; vapor pressure of solvent is directly prop. to mole fraction of solute Boiling point elevation: Tb = Kbm ; boiling point directly prop. to molality of solute
Freezing point depression: Tf = Kfm; freezing point depression directly prop. to molality of solute Osmotic pressure = MRT
KE = mv2/2
Hess' Law: Hrxn0 = Ha + Hb + ... ; enthalpy change is same as series of steps as if one reaction
Hrxn0 = (bond energies of reactants) - (bond energies of products)
H= E + PV
E = q + w = q - PV; difference in internal energy = heat and work Gibbs free energy: G = H - TS
Rate-law expression: xA + yB -> C + D rate = k[A]x[B]y
Arrhenius equation: k = Ae-Ea/RT ; relates rate constant to activation energy, temperature, and collision freq.
Chemical equilibrium: aA + bB -> cC + dD Keq = ([C]c[D]d)/ ([A]a[B]b) ; reaction quotient Q is same form for a specific time; can also use partial pressures rather than concentrations
KP = KC(RT)n
G0 = -RTln(K)
van't Hoff equation: ln(KT2/KT1) = H0/R (1/T1 - 1/T2) ; estimate equilibrium constant at another temperature
Kw = [H3O+][OH-] = 10-14 pH = -log([H3O+])
pKa = -log(Ka) ; large Ka -> small pKa -> strong acid
Henderson-Hasselbalch equation: pH = pKa + log([conj. base]/[acid])
Nernst equation: E = E0 - (2.303*R*T)/(n*F)*log(Q) = E0 - (0.0592*T)/n*log([Red]y/[Ox]x) ; calculates electrode potentials for concentrations and partial pressures other than standard values
nFE0 = 2.303*R*T*log(K)
G = -nFEcell
nuclear binding energy = (mass deficiency)*(speed of light)2 Half-life decay: t1/2 = ln(2)/k
Reaction orders:
Zero rate=k [A] = [A]0 - akt t1/2 = [A]0/(2*a*k) First rate=k[A] ln([A]0/[A]) = akt t1/2 = ln(2)/ak Second rate=k[A]2 1/[A] - 1/[A]0 = akt t1/2 = 1/(ak[A]0)
Constants and Numbers
Mole = 6.022*1023 particles
Electron = 1.75882*108 C/g, 9.109*10-28 g 1 g = 6.022*1023 amu
Planck's constant h = 6.6262*10-34 Js Rydberg's constant 1.097*107 m-1
Standard molar volume of ideal gas at STP: 22.414 liters per mole Universal gas constant R = 0.08206 (L*atm)/(mol*K)
Heat of vaporization of water = 2.26 kJ/g Specific heat of water = 4.18 J/(g*C) Heat of fusion of water = 334 J/g 1 faraday = 96485 Coulombs Joule = kg*m2/s2
Lists
Polyatomic Ions
Plus one: Na, K, NH4 ammonium, Ag, Cu+ cuprous
Plus two: Fe2+ ferrous, Cu2+ cupric, Zn, Mg, Ca, Hg mercuric, Hg2 mercurous Plus three: Fe3+ ferric, Al
Minus one: CH3COO acetate, F, Cl, Br, OH, NO2 nitrite NO3 nitrate, CN cyanide, ClO hypochlorite, ClO2
chlorite, ClO3 chlorate, ClO4 perchlorate
Minus two: SO3 sulfite, SO4 sulfate, CO3 carbonate, CrO4 chromate, Cr2O7 dichromate Minus three: PO4 phosphate, AsO4 arsenate
Acids
Acids: HNO3 nitric, HclO4 perchloric, HClO3 chloric, H2SO4 sulfuric, H3PO4 phosphoric, H3PO2
hypophosphorous
Ternary acids names: perXic (perXate), Xic (Xate), Xous (Xite), hypoXous (hypoXite) Strengths (inc.) : NH3, H2O, NH4, HCN, CH3COOH, HF, HNO3, HCl, HBr, HI, HclO4
Quantum Numbers
primary n (main energy level, 1,2,3...), subsidary or azimuthal l (shape of region, 0..n-1 = s,p,d,f,etc), magnetic ml
(spatial orientation -l..l orbitals), spin ms (1/2 or -1/2) Oxidation numbers
+1/-1: H +1: Li, Na, K
+2: Be, Mg, Ca, Cu, Zn +3: B, Al, Ga, Se +4: C, Si, Ge, Ti +5/-3: N +5: P +6/-2: S, Se -2: O -1: F, Cl, Br None: He, Ne, Ar
Oxides: O2- oxides, O22- peroxides, O2- superoxides Indicators
Methyl red: <4 red, >7 yellow; Bromthymol blue: <6 yellow, >8 blue; Phenolphthalein: <8 colorless, >10 red Orbital Orderings
1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d107p68s2 diagonals Bond Orders
H2 1, He2 0, B2 1, N2 3, O2 2 Solubility Rules
Soluble - common inorganic and low molecular weight organic acids, compounds of Group IA metals, nitrates, acetates, chlorates, perchlorates; Insoluble - most hydroxides, carbonates, phosphates, arsenates, sulfides Three Laws of Thermodynamics
First - total energy in universe is constant
Second - in spontaneous reactions universe tends towards state of greater disorder (greater entropy) Third - entropy of pure, perfect crystalline substance is zero at 0 K
Periodic trends
Inc. up and right: ionization energy, electron affinity negativeness (easily becomes anion), electronegativity (Fr least, F most, none for nobles)
Inc. down and left: atomic radii Radioactive decay
beta emission (electron ejected from nucleus as neutron is converted to proton),
positron emission or electron K-capture (positron ejected from nucleus as proton is converted to neutron),
alpha emission (helium nucleus with 2 protons and 4 neutrons is ejected) Valence Shell Electron Pair Repulsion Theory (VSEPR)
Bonds+electron pairs = 2 (linear, sp, 180), 3 (trigonal planar, sp2, 120), 4 (tetrahedral, sp3, 109.5), 5 (trigonal bipyramidal, sp3d or dsp3, 90,120,180), 6 (octahedral, sp3d2 or d2sp3, 90,180) hybrid - mixing of orbitals
Elements in the Earth
O 49.5%, Si 25.7, Al 7.5, Fe 4.7, Ca 3.4, Na 2.6 Most Commercially Used Acids
sulfuric, lime (CaO and Ca(OH)2), ammonia, NaOH, phosphoric, nitric
Elements
First Twenty
H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca f-Transitions
Lanthanides - 57, 58 cerium to 71 lutetium Actinides - 89, 90 thorium to 103 lawrencium Alkali Metals (IA)
Sodium (Na) - yellow glowing highway lamps, needed for life, soda lye (NaOH), baking soda (NaHCO3), table salt (NaCl)
Lithium (Li) - highest heat capacity, Li-Al aircrafts, dry cells, mental drugs, nuclear reactor heat transfer Potassium (K) - needed for life, saltpepper KNO3 fertilizer
Others: rubidium, cesium, francium Alkaline Earth Metals (IIA)
Calcium (Ca) - reducing agent, remove impurites, cheap base slaked lime Ca(OH)2, mortar, plaster of Paris 2CaSO4*H2O
Magnesium (Mg) - burns white in air; photo flashs, fireworks, anti-oxidation coating, plentiful in oceans Beryllium (Be) - X-ray window tubes
Strontium (Sr) - red glow; fireworks and flares Barium (Ba) - spark plugs
Group IIIA Boron (B)
Aluminum (Al) - most abundant in earth's crust and third overall; buildings, electrical transmission lines, reducing agent including thermite reaction with Fe2O3 in welding steel
Gallium (Ga) - melts in the hand; largest liquid state; transistors and high-temp. thermometers Indium (In) - soft bluish; electronics
Thallium (Tl) Noble Gases
Helium (He) - hot-air balloons, He/O2 deep-sea breathing, cryogenics Neon (Ne) - neon signs
Argon (Ar) - inert atmosphere for welding, incandescent light bulbs Krypton (Kr) - airport lights
Xenon (Xe) - short-exposure photographs Radon (Ra) - radiotherapy of cancer Halogens ("salt formers") (VIIA)
Fluorine (F) - pale yellow gas; prepared in Monel metal cell
Chlorine (Cl) - "green", yellow-green gas; made from NaCl; chlorinates hydrocarbons (chain eactions with radicals and termination steps), household bleaches, swimming pools
Bromine (Br) - "stench", dark-red liquid; eyeglasses, film, sedatives
Iodine (I) - "purple", violet-black crystalline; from dried seaweed; in growht-regulating hormone thyroxine
Group VIA
Oxygen (O) - breathing, oxidizing, many other uses
Sulfur (S) - mined by Frasch "hot water" process, "brimstone", yellow, stable rhombic and monoclinic forms; contact process used to make 40 million tons of sulfuric acid annually
Selenium (Se) - red glass coloring, copy machines, solar cells Tellurium (Te) - added to metals to increase electrical resistance Group VA
Nitrogen (N) - 78% of atmosphere, nitrogen cycle (nitrogen-fixation) Phosphorus (P) - present in all living things; used in fertilizers Group IVA
Carbon (C) - part of all organic compounds
Silicon (Si) - Al-Si alloys for aircraft, silicon dioxide occurs as quartz and flint; glass and computer chips
Organic Chemistry
Organic Compounds
Hydrocarbons - compounds of only carbon and hydrogen
alkanes - no multiple bonds between carbons (saturated), 1.54 A bond, 109.50, originally called
"paraffins" (little affinity)
CnH2n+2, methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, eicosane (20), triacontane (30), hectane (100);
branching: iso - one carbon off main chain, tert - two carbons off main chain, neopentane C(CH3)4;
alkyl groups - alkane attached to another group; iso - connecting carbon in middle of side chain, sec - 2o connecting carbon, tert - 3o connecting carbon
cycloalkanes - rings, CnH2n, substituted at axial and equatorial positions (switch in ring flip) so can be cis/trans
bicycloalkanes - two fused or bridged rings, decalin C10H18
alkenes - at least one double bond between carbons, three sp2 hybrid orbitals, rotation breaks pi bond, 1.34 A bond, 1200
CnH2n, ethene (ethylene), propene, butene, pentene, hexene, heptene, octene, nonene vinyl group CH2=CH- , allyl group CH2=CHCH2- ,
5,5-Dimethyl-2-hexene CH3CH=CHCH2C(CH3)3 , alkadiene has two double bonds, alkatriene has three double bonds
alkynes - at least one triple bond between carbons, 1.2 A bond, 1800
CnH2n-2, ethyne (acetylene), propyne, butyne, pentyne, hexyne, heptyne, octyne, nonyne 5-methyl-1-hexyne CH3CH(CH3)CH2CH2C=-CH , alkadiyne has two triple bonds,
alkatriyne has three triple bonds arenes (aromatic) - unsaturated cyclic hydrocarbons
annulene - monocyclic compounds with alternating single and double bonds
Huckel's Rule - planar monocyclic rings with 4n+2 delocalized electrons are aromatic antiaromatic - greater pi-electron energy than open chain; nonaromatic same; aromatic
less
benzene - C6H6 Kekule structure of alternating single/double C bonds phenyl group - benzene ring attached to another group
benzyl - benzene-CH2- attached to another group
benzenoid polycyclic aromatics including naphthalene C10H8
nonbenzenoid aromatic compounds including azulene C10H8
fullerenes - Kroto, Curl , and Smalley found C60 buckminsterfullerene, 20 hexagons and 12 pentagons, each sp2, can make salt with K
heterocyclic aromatic compounds including pyridine C5H5N, pyrrole C4H5N, furan C4H4O, thiophene C4H4S
benzene derivatives
fluorine - fluorobenzene methyl - toluene hydroxyl - phenol amine - aniline
hydrogen sulfate - benzenesulfonic acid carboxyl - benzoic acid
CH=CH2 (phenylethene) - styrene COCH3 (ester) - acetophenone OCH3 (ether) - anisole
two methyls - xylene (ortho, meta, para)
two hydroxyls - benzenediol (hydroquinone if 1,4) methyl and hydroxyl - cresol
carbonyl - benzaldehyde
carbonyl and meta OCH3 and para hydroxyl - vanillin CONH2 - benzamide
C=-N - benzenecarbonitrile
EAS benzene activating ortho-para directors (eg OH, O) and deactivating meta directors (eg NO2, have partial or full positive charge), halo groups are deactivating ortho-para directors
Functional groups
alkyl halides - halogen (F, Cl, Br, I) replaces hydrogen on an alkane; primary, secondary, or tertiary depending on number of carbons connected to the carbon bound to the halide chloroethane CH3CH2Cl, vinyl halide C=C-X, phenyl or aryl halide phenyl-X alcohols - hydroxyl group (OH) attached to sp3 carbon, R-OH; primary, secondary, or
tertiary depending on number of carbons connected to the carbon bound to the halide
methanol CH2OH, ethanol CH3CH2OH, 4-Methyl-1-hexanol CH3CH2C(CH3)CH2CH2CH2COH, 1,2-Ethanediol or Ethylene glycol HO-CH2CH2-OH,
3-penten-2-ol CH3CH=CHCHOHCH3 , 2-Methyl-4-pentyn-2-ol CH3C(OH)(CH3)CH2=-CH, not as strong of acids as phenols ethers - oxygen between carbons, R-O-R'
ethyl methyl ether CH3OCH2CH3 , 2-Methoxypentane CH3CH(OCH3)CH2CH2CH3 , epoxides (oxiranes) are 3-member cyclic ethers, crown ethers are cyclic polymers of
ethylene glycol and can be phase transfer catalysts, tetrahydrofuran (THF)
amines - nitrogen attached to at least one carbon; primary R-NH2, secondary two Rs and an H,
tertiary three Rs, ethylamine (ethanamine) CH3CH2NH2 , cyclic amines include pyrrole C4H4N, pyridine C5H5N, pyrrolidine C4H8NH, and purine C5H4N4 , more basic than amides, biological amines include nicotine, morphine, codeine, dopamine, serotonin, adrenaline (epinephrine), histamine
aldehydes - carbonyl group at end of chain, R-CO -H
formaldehyde CH2O, acetaldehyde (ethanal) CH3CHO, benzaldeyde C6H5CHO, 5-Chloropentanal ClCH2CH2CH2COH
ketone - carbonyl group in middle of chain, R-CO -R
acetone CH3COCH3, ethyl methyl ketone (butanone) CH3CH2COCH3, 4-Penten-2-one CH3COCH2CH=CH2 , benzopehenone (diphenyl ketone) C6H5COC6H5
carboxylic acids - carboxyl group attached to carbon, R-CO -OH
formic acid HCOOH, acetic acid CH3COOH, benzoic acid C6H5COOH,
4-Hexenoic acid CH3CH=CHCH2CH2COOH, dicarboxylic acids are called alkanedioic acids
amides - nitrogen and oxygen bound to carbon, R-CO -NR'R"
acetamide (ethanamide) CH3CONH2, N,N-Dimethylacetamide CH3CON(CH3)2 , cyclic amides are lactams
esters - two oxygens bound to carbon, RCOOR'
ethyl acetate (ethyl ethanoate) CH3COOCH2CH3 , tert-Butyl
propanoate CH3CH2COOC(CH3)3 , malonate, cyclic esters are lactones nitriles - nitrogen triple-bonded to carbon, C=-N, ethanenitrile CH3C=-N
Isomers
(Different compounds that have the same molecular formula)
Constitutional (structural) isomers - differ in connectivity; different physical properties Stereoisomers - differ only in arrangement of atoms in space, # of isomers < 2# of stereocenters
Diastereomers - molecules are not mirror images of each other
Cis (same side) / trans (opposite sides, more stable) for disubstituted alkenes E / Z system to name by prioritizing groups (same as R/S)
Enaniomers - molecules are nonsuperposable mirror images of each other
R (rectus) / S (sinister) system to name by prioritizing groups attached to stereocenter, higher atomic number means higher priority; developed by Cahn, Ingold, and Prelog Optically active (rotate plane-polarized light)
Clockwise dextrorotatory or counterclockwise levorotatory Specific rotation [] = /(c*l) observed/((g/mL) * (dm)) Equimolar mixture of two enantiomers is racemic
Meso compounds are achiral despite having tetrahedral atoms with 4 different attached groups because it has a plane of symmetry
Fischer projection formulas represent chiral molecules
Dimethylcyclohexanes: 1,4 diasteromers, 1,3 meso, 1,2 enantiomers Resolution - separation of enantiomers of a racemic form
Allenes - chiral molecules with C=C=C instead of tetrahedron
Stereochemistry
(3D aspects of molecular structure)
Conformational analysis of alkanes - Newman projection and sawhorse formulas, torsional strain:
anti < gauche < eclipsed
Ring strain - measure by heat of combustion (greater heat means more potential energy and less stable), cyclohexane most stable and cyclopropane least stable cycloalkanes, due to angle strain and torsional strain; chair conformation of cyclohexane has no angle or torsional strain; boat conformation has
torsional strain only; strain: chair < twisted < boat; diaxial interactions cause steric strain, less if equatorial than axial
Types of Reactions
Substitution, addition, elimination, rearrangement Heterolysis produces ion, homolysis produces radicals
Electrophiles seek extra electrons, nucleophiles seek proton or other positive center Nucleophilic substitution reactions
Nucleophile + Alkyl halide --> product + halide ion Nucleophile has unshared electron pair
Leaving groups (nucleofuges) such as halides become stable weak base, triflate ion CF3SO3- > I > Br > Cl > F
SN2 reaction rate proportional to concentrations of both reactants, nucleophile approaches leaving group carbon from backside causing R/S inversion of configuration, goes via transition state SN1 three-steps with first slowest so rate depends only on alkyl halide concentration, product is
racemic since carbocation intermediate is achiral
Structure of substrate can slow rate if it blocks access (steric hindrance); methyl > primary >
secondary >> tertiary; stability of carbocation determines SN1 rate; vinyl and phenyl halides unreactive
Hammond-Leffler postulate: structure of transition state resembles the stable species that is nearest it in free energy
Polar protic solvents may slow reaction by solvating nucleophile so SN2 reactions may be faster in polar aprotic solvents (such as DMSO dimethyl sulfoxide, DMF N,N-dimethylformamaide, DMA dimethylacetamide)
Elimination reactions
E2 reaction rate proportional to concentrations of both reactants; SN2 is favored with primary halides but E2 with secondary halides; high temperature and strong sterically hindered base favor elimination
E1 reaction forms carbocation like SN1 and makes some substitution product also
Reactions
Alkanes
Hydrogenation - make alkanes from alkenes with H2 and Ni or Pt
Reduction of alkyl halides - make alkanes from alkyl halides with H+, Zn, and acid
Corey-Posner Whitesides-House Synthesis - make alkanes from organic halides via lithium dialkylcuprate (R2CuLi) in diethyl ether
Enantioselective reactions produce more of one enantiomer than another Hydrolysis: ester + water --> carboxylic acid + alcohol
Alkyl Halides
Functional group transformations - make almost anything from alkyl halide
Dehydrohalogenation - make alkenes from alkyl halides with ethanol and sodium alkoxide, or 1,2
eliminations; Zaitsev's Rule: forms most stable, most highly substituted alkene; Hofmann's Rule: exception to Zaitsev's Rule, forming less substituted alkene; anti periplanar transition conformation preferred to syn periplanar
Alkenes
Catalytic hydrogenation - make alkanes from alkenes with H2 and fine metal (Ni, Pd or Pt) Syn Hydrogenation - make Z-alkenes from alkynes with H2 /Ni2B or Lindlar's catalyst
Anti Hydrogenation - make E-alkenes from alkynes with Li, etheamine and ammonium chloride, vinylic radical intermediate with one radical carbon across double bond
Dehydration of Alcohols - make alkenes from alcohols with strong acid, 30 alcohols fastest because they make more stable E1 carbocation
Debromination of Vicinal Dibromides - make alkenes from alkyl halides with bromides vic (on adjacent carbons, not gem, on same carbon) with Zn and formaldehyde or NaI and acetone
Addition of Hydrogen Halides to Alkenes - make alkyl halide from alkene with HX; Markovnikov's Rule:
hydrogen atom adds to carbon of double bond that already has greater number of hydrogen atoms, yielding more stable carbocation intermediate; regioselective reaction, producing mostly one of two possible constitutional isomers; exception if HBR is added with peroxides; forms radicals
Addition of Sulfuric Acid - make alcohols from alkenes with cold sulfuric acid via alkyl hydrogen sulfate intermediate, then heating
Acid-Catalyzed Hydration - make alcohols from alkene with water and acid
Addition of Bromine and Chlorine to alkenes - make vic alkyl halide from alkane and dimolecular Br or Cl with sunlight and CCl4; red brown Br color goes away as test for alkenes; stereospecific to anti addition to cycloalkene
Halohydrin Formation - make halohydrin (-CXCOH-) from alkene with dimolecular Br or Cl and water Oxidations of Alkenes - make glycols (1,2 diols) from alkenes with KMnO4 and OH- or OsO4 (osmium
tetroxide) via syn hydroxylation and osmate intermediate
Oxidative Cleavage of Alkenes - make carboxylic acid from alkene with hot permanganate Ozonolysis of Alkenes - make aldehydes and/or ketones from alkenes with ozone and Zn / water
Addition of Bromine and Chlorine to Alkynes - make trans-dihaloalkenes or tetrahaloalkanes with one or two equivalents of dimolecular halogen
Addition of Hydrogen Halides to Alkynes - make gem-dihalide from alkyne with 2 HX; anti-Markovnikov intermediate if peroxides used
Radical Reactions
Radical Reactions - alkane + halogen --> halo, dihalo, trihalo, and/or tetrahaloalkane + HX with light;
initiation, propagation, and terminating steps; bromine less reactive but more selective Chain growth polymers - monomers combine using peroxides to form radical intermediates Autoxidation - organic compound reacts with oxygen to form hydroperoxide
Ozone depletion - radical reactions with CF2Cl2 convert O3 to O2 via radicals Alcohols and Ethers
Oxymercuration / Demercuration - make alcohols from alkenes with mercuric acetate and THF
Hydroboration - make organoborane from alkene and boron hydride with THF via borane intermediate;
anti-Markovnikov
Alcohol Reactions - make protonated alochols from alcohols with strong acid or protonated ethers from alcohols
Alcohol Reactions - make mesylates (methanesulfonates) and tosylates (toluenesulfonates) from alcohols and sulfonyl chlorides
Alcohols into Alkyl Halides - make alkyl halides from alcohols with hydrogen halides, phosphorus tribromide, or thionyl chloride
Synthesis of Ethers - make ethers from alcohols with H+
Williamson Synthesis of Ethers - make ethers from sodium alkoxide with alkyl halide, alkyl sulfonate, or alkyl sulfate; can make sodium alkoxides from phenols
Silylation - make trimethylsilyl ethers from alcohols with chlorotrimethylsilane, protecting OH Ether Reactions - make oxonium salts from ethers and hydrogen halide
Epoxidation - make epoxide from alkene and peroxy acid
Alcohols by Reduction - make alcohols from carboxylic acids and lithium aluminum hydride or esters and high pressure or aldehydes/ketones and sodium borohydride
Oxidation of Alcohols - make aldehydes from alcohols with potassium dichromate and sulfuric acid or pyridinium chlorochromate (PCC) and dichloromethane
Oxidation of Alcohols - make carboxylic acids from alcohols with potassium permanganate and hydroxide Oxidation of Secondary Alcohols - make ketones from secondary alcohols with sodium dichromate and
acetone
Grignard Reagents - make Grignard reagents from organic halide and Mg with ether Grignards with Oxiranes - make primary alcohols from oxiranes with Grignard
Grignards with Carbonyls - make primary/secondary alcohols from aldehydes with Grignard or tertiary alcohols from ketones with Grignard
Organolithium reagents and sodium alkynides work like Grignard Conjugated Unsaturated Systems
Shell Process - make allyl chloride from propene and chlorine via radicals
Bromination of Allyl - make allyl bromide from propene with N-Bromosuccinimide (NBS)
Electrophilic Attack on Conjugated Dienes - HX adds to one of two double bonds, or H to one and X to the other and double bond in between (1,2 and 1,4 additions)
Diels-Alder Reaction - make an adduct from conjugated diene and double bonded dienophile; forms two sigma bonds at expense of two pi bonds; syn addition and cis and endo
Electrophilic Aromatic Substitution Reactions of Aromatic Compounds Bromine with Benzene - reacts with Lewis acid catalyst by substitution not addition
Electrophilic Aromatic Substitution Reactions - arene + electrophile --> arene-electrophile + H+via nonaromatic carbocation called arenium ion
Halogenation - make halobenzene from benzene and Br2 or Cl2 with Lewis acid FeBr2 or FeCl2
Nitration - make nitrobenzene from benzene and hot nitric acid with sulfuric acid
Sulfonation - make benzene-sulfonic acid from benzene and fuming sulfuric acid (extra SO3)
Friedel-Crafts Alkylation - make alkylbenzenes from alkyl halides and benzene with AlCl3, or from alkene and acid, or from alcohol and acid
Friedel-Crafts Acylation - make acylated benzene from benzene and acetyl halogen or carboxylic
anhydride with AlCl3; poor yield if strong withdrawing groups are present on ring; major product form more
stable carbocation; often get polyalkylations
Clemmensen Reduction - make alkyl benzene from ketone from Friedel-Crafts Acylation with amalgamated zinc and HCl reflux
Birch Reduction - reduce benzene to 1,4-Cyclohexadiene with alkali metal, ammonia, and alcohol Aldehydes and Ketones
Aldehyde Synthesis - make aldehydes from primary alcohols with PCC and dichloromethane
Aldehyde Synthesis - make aldehydes from acyl chlorides with lithium tri-tert-butoxy-aluminum hydride Aldehyde Synthesis - make aldehydes from esters or nitriles with DIBAL-H and hexane
Ketone Synthesis and Tautomerization - make ketones from alkynes with sulfuric acid and mercuric ions, resulting in keto-enol forms which tautomerize; Markovnikov; enol form more common with beta- dicarbonyl
compounds; ketone can lose its optical activity by converting to achiral enol form
Ketone Synthesis - make ketones from acyl chlorides with lithium dialkylcuprate or from nitriles with Grignard or organolithium
Nucleophilic Substitutions of Carbonyl - RCOH + Nu-H --> RCNuHOH; aldehydes more reactive Hydrates - make hydrates (gem diols, RCH(OH)2) from aldehyde and water with acid or base Hemiacetals - make hemiacetals (RCH(OR')(OH)) from aldehyde or ketone and alcohol
Acetals - make acetals (RCH(OR')2) from adehyde or ketone and alcohol with gaseous HCl; may serve as a protecting group for subsequent reactions, as it can be removed with acid and water
Thioacetals - make thioacetals (HCR(SR')2) from aldehyde or ketone and thiols with acid Desulfurization - make hydrocarbons from thioacetals and hydrogen with Raney nickel Imines - make imines (C=N-R) from aldehyde or ketone and primary amine
Wolff-Kishner Reaction - reduce C=O to CH2 in aldehyde or ketone with hydrazine (H2NNH2) and base, via hydrazone (C=NNH2)
Semicarbazide - reduce C=O to CH2 in aldehyde or ketone with semicarbazide (H2NNHCONH2) via semicarbazone
Cyanohydrins - make cyanohydrins (RHC(OH)(CN)) from aldehydes or ketones with hydrogen cyanide (HCN) Wittig Reaction - make alkenes and triphenylphosphine oxide from aldehyde or kentone and phosphorus
ylide (phosphorane, (C6H5)3P-CRR') via betaine intermediate
Reformatsky Reaction - make beta-hydroxy esters from aldehydes or ketones and alpha-bromo ester with zinc and benzene
Baeyer-Villiger Oxidation - make carboxylic esters from ketones and peroxy acid
Haloform Reaction - make multiple halogen substitutions on alpha-carbon of methyl ketone with X2 and base
Aldol Additions - make aldol (aldehyde alcohol) from aldehyde with dilute NaOH; can have crossed aldol reactions if start with two different carbonyl compounds
Aldol Condensation - make enal (unsaturated aldehyde) from aldol via dehydration; can also condensate to make unsaturated amines or nitriles from nitroalkenes or nitriles
Claisen-Schmidt Reaction - crossed aldol reactions using one ketone; make unsaturated ketones from aldehyde and ketone with base; used with geranial and acetone to make Vitamin A
Cyclizations via Aldol Condensations - make 5 or 6 membered rings from dialdehyde, diketone, or keto aldehyde with base
Additions to alpha-beta Unsaturated Aldehydes and Ketones - simple addition and conjugate addition (with keto and enol forms) reactions both occur
Michael Additions - conjugate addition of enolate ions to alpha-beta unsaturated carbonyl compounds with base
Robinson Annulation - uses Michael addition and simple aldol condensation to build one ring onto another Carboxylic Acids, Esters, and Amides
Grignards - make carboxylic acids from Grignard reagent and carbon dioxide with acid
Nucleophilic Substitutions of Acyl Carbon - replace leaving group on acyl carbon with nucleophile Acyl Chloride Synthesis - make acid chlorides from carboxylic acids and thionyl chloride (SOCl2) or
phosphorus pentachloride (PCl5)
Synthesis of Carboxylic Acid Anhydrides - make carboxylic acid anhydrides (R-COOCO-R') from carboxylic acid and acyl chloride with pyridine
Esterification - make esters by condensation of carboxylic acids and alcohols with acid or from acyl chlorides and alcohols or from carboxylic acid anhydrides and alcohols
Saponification - make alcohol and carboxylate salt from hydrolysis of ester by base
Amide Synthesis - make amides from acid chlorides or acid anhydrides or esters and amines or ammonia, or from carboxylic acids and ammonia with dicyclohexylcarbodiimide (DCC)
Amide Hydrolysis - make carboxylic acid and ammonia from amide and acid or base Amide Dehydration - make nitriles from amides with phosphorus pentoxide P4O10
Nitrile Hydrolysis - make carboxylic acids from nitriles with acid or base
Hell-Volhard-Zelinski Reaction - make alpha-halo carboxylic acids from aliphatic carboxylic acids and Br2
or Cl2 with phosphorus
Decarboxylation of Carboxylic Acids - remove carboxyl group from beta-keto carboxylic acids by heating, or from carboxyl radicals
Dicarbonyl Compounds
Claisen Condensation - make beta-keto esters from esters and sodium ethoxide, via aldol addition, enolate anion attack, and acid-base reaction; can be crossed with two esters if one ester has no alpha hydrogens Dieckmann Condensation - make 5 or 6 membered rings by an intramolecular Claisen condensation
Acetoacetic Ester Synthesis - make substituted acetones from acetoacetic ester Malonic Ester Synthesis - make substituted acetic acid from malonic ester
Knoevenagel Condensation - active hydrogen compounds condense with aldehydes and ketones, like aldol condensations, with weak base
Mannich Reaction - make Mannich bases from enols and formaldehyde and primary or secondary amine Stork Enamine Reaction - make enamines from aldehydes or ketones with secondary amines, and then
acylate or alkylate the enamines or use in Michael Additons Amines
Nucleophilic Substitution Reaction of Amines - make amines from alkyl halide and ammonia, optionally via azide (N3-) ion intermediate
Preparing Aromatic Amines - make aromatic amine from arene with nitric acid and sulfuric acid and then reduction with H2 or iron and HCl
Reductive Amination - make amines from aldehyde or ketone and ammonia or an amine Hofmann Rearrangement - make amines from amides and X2 with NaOH
Curtius Rearrangement - make amine from acyl chloride with NaN3 via acyl azide and isocyanante intermediates
Diazotization Reaction - make unstable aliphatic diazonium salts from primary aliphatic amines and nitrous acid (HONO, made from HCl and NaNO2 in situ)
Sandmeyer Reaction - make Cl, Br, or CN substituted arenes from arenediazonium salts and CuCl, CuBr, or CuCN
Diazonium Replacements - make I, F, or OH substituted arenes from arendiazonium salts and KI, HBF4, or Cu2OH
Deamination by Diazotization - replace diazonium group with hydrogen using hypophosphorous acid Diazo Coupling Reactions - make azo compounds (Ar-N=-N-Ar) from arenediazonium ions and reactive
aromatic compounds
Synthesis of Sulfonamides - make sulfonamides (R-NH-SO2Ar) from primary or secondary amine and sulfonyl chloride
Hofmann Elimination - make alkene, water, and tertiary amine from quaternary ammonium hydroxide in E2 elimination
Cope Elimination - eliminate dialkylhydroxylamine from tertiary amine oxides Phenols
Dow Process - make phenol from chlorobenzene and NaOH by heating at high pressure and using HCl
