Concepts (*TBD Unit 5-9)

VSEPER

Valence Shell Electron Pair Repulsion

• electrons are the same charge and repel one another

2 Electron Domains

Linear

• 180 degrees

3 Electron Domains w/0 Lone Pairs

Trigonal Planar

• 120 degrees

3 Electron Domains w/1 Lone Pairs

Bent

• 120 degrees

4 Electron Domains w/0 Lone Pairs

Tetrahedral

• 109 degrees

4 Electron Domains w/1 Lone Pairs

Trigonal Pyramidal

• 109 degrees

4 Electron Domains w/2 Lone Pairs

Bent

• 120 degrees

5 Electron Domains w/0 Lone Pairs

Trigonal Bipyramidal

5 Electron Domains w/1 Lone Pairs

Seesaw

• 90 degrees

5 Electron Domains w/2 Lone Pairs

T-shape

• 90 degrees

5 Electron Domains w/3 Lone Pairs

Linear

• 90 degrees

6 Electron Domains w/0 Lone Pairs

Octahedral

• 90 degrees

6 Electron Domains w/1 Lone Pairs

Square Pyramidal

• 90 Degrees

6 Electron Domains w/2 Lone Pairs

Square Planar

• 90 degrees

6 Electron Domains w/3 Lone Pairs

T-shaped

6 Electron Domains w/4 Lone Pairs

Linear

• 90 degrees

Coulomb’s Law

More attraction when

• Distance between charged particles is small

• Magnitude of charge is greater

Potential Energy Graph

Lowest pt. = when bond is most stable

Bond Strength

Stronger when bonds are shorter/when double/triple bonds (compared to single bonds)

Structure of Ionic Solids

Lattice structure aka crystalline where you alternate between the anion and the cation

• Anions are drawn larger than cations because they hold more electrons

Interstitial Alloy

Occurs when there is a big difference in atom size (ex: C and Fe)

• density increased

• less malleable and ductile

• more rigid

Substitutional Alloy

Occurs when there is a small difference in atom size (ex: Cu and Zn)

Resonance

When you can draw a molecule in multiple arrangements

Formal Charge

# of Valence - # of Non-bonding Electrons - # of Covalent Bonds

Hybridization

3 domains = sp2

4 domains = sp3

Sigma vs Pi Bonds

Sigma = electron pair is shared

Pi = second/second + third bond formed in a double or triple bond

Intermolecular vs Interparticle Forces

IMFs = between molecules

IPFs = within molecules

Dipole-dipole Interactions

• between 2 polar molacules

• lead to higher melting points and boiling points

Hydrogen Bonding

(special case of dipole-dipole)

• hydrogen atom of a molecule is attracted to unshared electron pair on F, O, N of a neighboring molecule

  • “H-bonding is FON”

Ion-induced Dipole

• attraction between charged ion and nonpolar molecule

• ion distorts the electron cloud of nonpolar molecule

Dipole-induced dipole

• polar and nonpolar IMF

• polar induces temporary dipole

• larger molecules are more polarizable (by Coulomb’s)

Induced-dipole-induced-dipole (London Dispersion Forces)

• attraction between 2 nonpolar molecules because of temporary dipoles

• more electrons = more polarizable = stronger attraction

Network Covalent Solids

2-dimensional = soft and slippery

3-dimensional = interlocking layers (of carbon)

• high melting point

• insoluble

• poor conductors except graphite

Vaporization (Evaporation)

Conversion of a liquid to a gas

• aka how easy it is to break bonds

Phase Diagram

• who relationships between solid, liquid, and gas

• triple point = where all states exist in equilibrium

Vapor Pressue

Pressure exerted by vapor in equilibrium w/liquid

Ideal Gas Law

PV = nRT

Boyle’s Law

Volume and pressure = inversely proportional

P₁V₁ = P₂V₂

• only true at low pressures

Charles’s Law

Volume and temperature = directly proportional

V₁/T₁ = V₂/T₂

Gay-Lussac’s Law

P₁/T₁ = P₂/T₂

Dalton’s Law of Partial Pressures

Pressure of a mixture = sum of pressures of different components

Diffusion vs Effusion

Kinetic Molecular Theory

Assumes…

• all particles are in constant, random, motion

• all collisions are perfectly elastic

• gas particles are so small the volume is neglected

• average kinetic energy is kelvin temperature

• higher temperature = higher average kinetic energy

• collisions with walls = pressure of gas

Deviation from Ideal Gas Law

Low temperature = moving less fast so IMFs still matter

Small volume = hit the sides more bcs of particle size

Separation of Mixtures (List Methods)

• distillation = separation by IMFs and their impacts on vapor pressure

• chromatography = by polarity

Chromatography

Separates by polarity

• have stationary phase = paper or stuff inside the column

• have mobile phase = solvent

Beer Lambert Law

relates absorption of light to molar absorptivity, path length, and concentration

pH and pOH

pH = -log[H+]

pOH = -log[OH-]

Polyprotic Acids and Bases

• can donate more than one proton

Ammonium

NH4+

Acetate

CH3COO-

Nitrate

NO3-

Nitrite

NO2-

Perchlorate

ClO4- = Perchlorate

Chlorate

ClO3

Chlorite

ClO2

Hypochlorite

ClO

CN-

Cyanide

OH-

Hydroxide

MnO4-

Permanganate

SO4-2

Sulfate

SO3-2

Sulfite

HSO4-

Hydrogen sulfate

CO3-2

Carbonate

PO4-3

Phosphate

CrO4-2

Chromate

O2-2

Peroxide

SCN-

Thiocyanate