UNIT 1
Moles, atoms, atomic mass (EZ)
6.02x10^23
Electron configs
Coulomb's law; Greater magnitude of charge and distance
Valence electrons are farther
Each peak in a photoelectron spectrum is a sublevel
Peaks on the left require more energy
Anion –, cation +
UNIT 2
Ionic bonds, electrostatic forces, + and -, brittle, high melting point, conduct electricity when dissolved
Covalent bonds, two nonmetals, lower melting points, don’t conduct electricity
Polar; share unequally
nonpolar; share equally
Ionic compounds have a repeating lattice structure, cations and anions alternate
Metallic; a sea of electrons
Lewis diagram
VSEPR
Linear: 180 degrees
UNIT 3
Intermolecular forces
LDFs: usually weakest except in large molecules, found in ALL molecules, more electrons = more polarizable=stronger LDFs
Dipole-dipole forces (POLAR molecules), moderate strength
Hydrogen bonding, usually strongest, FON
Solids, crystalline
Liquids have more freedom of motion
Gases have independent motion
PV=nRT
Gas acts most ideal at high temp and low pressure, also very small molecules
High temp, higher average kinetic energy, greater velocity
Molarity mol/L
“Like dissolved like”
Polar molecules dissolve in polar solvents(like water) because of dipole-dipole or h-bond forces between the solute and solvent
Nonpolar molecules dissolve in nonpolar solvents because of LDFs
Planck’s constant
The higher the absorbance, the higher the concentration
UNIT 4
Omit spectator ions
Net ionic equation
Coefficients form mole ratio
In precipitation reactions, two solutions are mixed, and a solid is formed
Redox reactions, OIL RIG
Acid-base reactions, acid and bade form conjugate acid/base. Acid proton donor, base proton acceptor
UNIT 5
Coefficients determine rate
Double concentration and rate quadruples: 2nd Order
Double concentration and rate doubles: 1st Order
Double concentration and rate don't change: 0th Order
0 order = [A]sub t - [A]sub 0 = -kt
1st order = ln[A] sub t - ln [A] sub 0 = -kt
2nd order = 1/[A]sub t - 1/[A]sub 0 = kt
Reaction mechanism
Slow step determines the rate of reaction
Molecules have to collide with enough energy and the correct orientation to react
Activation energy, is the energy required to start
Net loss of heat to the surroundings; exothermic
Speed up reaction: higher temp, higher concentration, larger surface area, add catalyst
Catalyst lowers activation energy
UNIT 6
Endothermic absorbs heat, exothermic releases heat
q=mCdeltaT
Heat change= change in enthalpy
Estimate using bond enthalpies
Enthalpy of formation products-reactants
Hess’s law adds delta H together
UNIT 7
Equilibrium DOES NOT STOP reaction
Forward and reverse reaction rates are equal
Ration quotient = Q
No liquids or solids
Q = k at equilibrium
k>1 lots of product, equilibrium is at the right
K<1 lot of reactant, the equilibrium lies to the left
Given initial concentration/pressure, use an ICE chart
Le Chatliers, the reaction will try to compensate
UNIT8
pH=-log[H+]
Strong acids and strong bases ionize completely
Weak acids and bases are equilibrium problems (ice chart)
ACid-base situations, try to find concentration
The endpoint is a complete reaction
Halfway point pH=pKa
Buffers:weak acid and its conjugate base
Hendresson-hasselbpach equation
pH= pKa + log([A-]/[HA])
UNIT 9
Entropy (S) disorder
Solids -> gases increasing entropy
Higher temp = more entropy
Gibbs free energy, thermodynamic favorability
ΔG=ΔH-T(ΔS)
Negative G is favored
ΔG = -RTlnK
Every galvanic cell has two half-reactions, redox
RED CAT and AN OX (reduction at the cathode, oxidation at the anode)
Electrons move through the wire FAT CAT (from the anode to the cathode)
The salt bridge allows ions to flow freely through the cell
Anions to the anode, cations to the cathode
Voltage calculated using standard reduction potentials
As the call runs, the voltage slowly drops until it reaches 0 (dead battery, equilibrium)
Standard conditions, 25 degrees C, 1 atm, 1 M
Nernst equation for nonstandard conditions (E = E° - (RT/nF)lnQ
Galvanic cells are thermodynamically favored
ΔG = -nFE
External energy powers the electrolysis process
I = q/t (Current in amps = coulombs/time in seconds)