Liquidsand

Solids

Jenna Mandel and Shela WuAP Chemistry - 7

CHAPTER 10

Intermolecular Intramolecular

Condensed States of Matter

held together by intermolecular forces

VSBETWEEN MOLECULES KEEPS MOLECULE TOGETHER

When something undergoes a phase change, the changes occur in the intermolecular forces.

Dipole-Dipole Forces

Occurs between two polar molecules

HYDROGEN BONDING

Strong form of dipole-dipole attractionsOccurs in molecules with hydrogen that is bonded with an element with a high E.N.High difference in electronegativity & small size contributes to its great strength

London Dispersion

ForcesOCCURS BETWEEN 2 NON-POLAR MOLECULES

INSTANT-ANEOUS DIPOLES IN LARGE

ATOMS, CAN BE MORE SIGNIFICANT THAN DIPOLE-DIPOLE FORCES

LIQUIDS

The Liquid State

measure of liquid’s resistance to flow

surface tension the resistance of a liquid to an increase in its surface area

capillary action spontaneous rising of a liquid in a narrow tube a result of adhesion and cohesion

Concave shape of meniscus shows adhesive > cohesive

Viscosity:adhesive versus cohesive

liquid particles attracted to themselvesforce between liquid and surrounding

describes the locations of the pieces in a crystalline solid

CRYSTALLINE SOLIDS

LATTICE

UNIT CELL smallest repeating unit of the lattice

as apposed to amorphous solids…

Types of Crystalline Solids

IONIC SOLIDSions at lattice points

Types of Crystalline Solids

MOLECULAR SOLIDS

small molecules at lattice points

ATOMIC SOLIDS

atoms at lattice points

Metallic SolidsPositively charged & held together by neutrons.

Delocalized electron sea theory

Types of Crystalline Solids

ATOMIC SOLIDS

atoms at lattice points

Network SolidsAtoms bond covalently in a continuous network.

Strong Bonds -> High mp & bp Do not conduct electricity

Types of Crystalline Solids

ATOMIC SOLIDS

atoms at lattice points

Group 8A SolidsNoble gases bonded with London Dispersion

ForcesOccur at very low temperatures!

Types of Crystalline Solids

MET

ALS

It’s ductile!

It’s malleable!

strong & nondirectional

ELECTRON SEA MODEL

metal cations in valence e-

conduct heat and electricitymalleable and ductile

MOLECULAR ORBITAL MODEL

Diamond

Graphite

VERSUS

Hardest naturally occurring substance

sp3 hybridization

large gap between filled and empty levels in

energy diagram

carbon surrounded by a tetrahedral

Slippery, black, & a conductor

Layers of carbon atoms in 6 member rings

sp2 hybridization

weak bonding between layers accounts for

slippery texture

PHASE CHANGES

Heat of VaporizationENERGY NEEDED TO VAPORIZE A MOLE OF LIQUID

When does a liquid boil?its vapor pressure

EQUALSpressure of the environment

CLAUSIUS-CLAPEYRON EQUATION

1

2

vap, vap

vap, 2 1

1 1ln =

T

T

P H

P R T T

ΔHvap = enthalpy of vaporizationR = 8.3145 J/K·molT = temperature (kelvin)C=constant

Determine heat of vaporization, and can also be used to find

Pvap

Rate of Condensation and Evaporation

Rate of evaporation

remains constant while rate of condensation increases as number of

molecules in vapor phase increases,

until they become equal, and thus

reach equilibrium.

REPRESENT PHASES AS A FUNCTION OF TEMPERATURE AND PRESSURE

PHASE DIAGRAMS