Liquids, Solids, and Intermolecular Forces (Unfinished)

qualities IMFs affect

• boiling points

• Viscosity

• Solubility

• Phase Changes

• capillary action

IMFs (weakest to strongest)

1. dispersion

2. dipole-dipole

3. hydrogen bonding

4. ion-dipole

Dispersion forces

exists in all particles due to electrostatics (other electron to nucleus attraction) = induced dipoles, Increases with size, and surface area

Dipole-Dipole forces

between polar molecules

Hydrogen bonding

between (FON) H—F, H—O, or H—N bonds between molecules

Ion-Dipole forces

between ionic and polar compounds (ex. NaCl + H2O)

The closer the bond…

The lower the energy of the molecule (Coulomb’s Law)

Coulomb’s Law

(1/(4pie0)) x ((q1 q2)/ r): PE decreases - closer electrons and protons get

induced dipole

momentary shift in electron density, molecule - molecule (can occur within diatomic molecules)

Mnemonic for homonuclear diatomic elements

Have No Fear Of Ice Cold Beer (H, N, F, O, I, Cl, Br)

alcohol diff from alkanes

R + hydroxide

adhesive forces

interactions between unlike particles

cohesive forces

interactions between like particles

Concave meniscus

greater adhesive forces then cohesisve

Convex meniscus

greater cohesive forces than adhesive

Capiliary action

liquid flowing againstgravity up a narrow tube

surface tension

measue of the imbalance in cohesive forces within the water

surface water vs bulk water

SW has less molecules to bing to and so is more ready to interact with things that touch surface

viscosity

measure of resistance of a fluid to flow

units: Poise (1 P = 1 g/(cm x sec)

Factors that change viscosity

molecular shape, Molar mass, Temperature

Vapor Pressure

pressure of gas in dynamic equilibrium with liquid (Against covers and walls)

dynamic equilibrium

rate of evaporation = rate of condensation

normal boiling point

BP at standard pressure (1 atm)

volatile

evaporates

Heat of Vaporization

energy required to convert 1 mole from liquid to gas (enthalpy of vaporization)

Heat of fusion

energy required to convert 1 mole from solid to liquides (enthalpy of vaporization)

Deposition

gas to solid

sublimation

solid to gas

fusion

solid to liquid (melting)

vaporization

liquid to gas

solidification

liquid to solid

Triple Point

temp and pressure all three phases coexist in equilibrium

Critical point

temp and pressure where liquid and gas have the same energy