1

Types of Types of SolidsSolids

Chap. 13: Day 4b

2Metallic and Ionic Metallic and Ionic SolidsSolids

Sections 13.6-8Sections 13.6-8

Metallic and Ionic Metallic and Ionic SolidsSolids

Sections 13.6-8Sections 13.6-8

3

Properties of SolidsProperties of Solids

1. 1. Molecules, atoms or ions locked into a CRYSTAL LATTICE

2. Particles are CLOSE together

3. STRONG IM forces

4. Highly ordered, rigid, incompressible

ZnS, zinc sulfideZnS, zinc sulfide

4

5

Types of SolidsTypes of SolidsTable 13.6Table 13.6

TYPETYPE FORCE Properties . FORCE Properties .

Ionic Ionic Ionic Ionic Hard, brittle, High MP Hard, brittle, High MP

poor conductorpoor conductor

Metallic Electrostatic Metallic Electrostatic Malleable, Range of MP Malleable, Range of MP

good conductorgood conductor

MolecularMolecular Dipole Soft, Low of MP Dipole Soft, Low of MP

Ind. Dipole poor conductorInd. Dipole poor conductor

NetworkNetwork Extended Extended Range of MP & hardnessRange of MP & hardness

covalent covalent poor conductorpoor conductor

6

Network SolidsNetwork Solids

DiamondDiamond

GraphiteGraphite

7

Network SolidsNetwork Solids

A comparison of diamond (pure carbon) A comparison of diamond (pure carbon) with silicon.with silicon.

8Atom Packing in Unit Atom Packing in Unit CellsCells

Assume atoms are hard spheres and that crystals are built by PACKING of these spheres as efficiently as possible.

9

PROPERTIES

OF LIQUIDS

Chap. 13: Day 4a

Intermolecular Forces

The forces BETWEEN molecules. Holds the molecules together. At a set temperature:

What phase has the strongest force? Solids

What phase has the weakest forces? Gases (vapor)

Viscosity•the resistance of a fluid to flow

Thick fluids have high viscosity

Liquid Properties Surface Tension- Ability of liquid molecules to

hold on to each other. Apparent “skin” affect Ex. Over filling a liquid in a glass with out the

liquid spilling

Hg

Liquid Properties

Capillary Rise- the tendency of a liquid to rise in a small diameter tube due to the surface tension of the liquid.

Vapor Pressure

The pressure exerted by a vapor in equilibrium with its liquid state.

The pressure at which liquid changes to vapor

Liquids with high vapor pressures turn into vapors very easily. (Volatile)

Ex. Gasoline, perfume

Once equilibrium is reached, the vapor particles will begin to condense back to a liquid

Boiling Point

The temperature at which the vapor pressure of the liquid equals the atmospheric pressure

The entire liquid is changing state, not just the surface.

Water boils at 1000C

at standard P

Vapor Pressure vs Temperature

24

TWO ways to change PHASE

•Temperature

Pressure

PHASE CHANGES:

25

Almeltingpoints

SOLID

LIQUID

26

Boiling points: Liquid to Vapor

Water

LIQUID

GAS

27Phase DiagramsPhase Diagrams

28

TRANSITIONS TRANSITIONS BETWEEN BETWEEN PHASESPHASESSection 13.10Section 13.10

Lines connect all conditions of T and P where EQUILIBRIUM exists between the phases on either side of the line.

(At equilibrium particles move from liquid to gas as fast as they move from gas to liquid, for example.)

29

Phase Equilibria — WaterPhase Equilibria — Water

Solid-liquidSolid-liquid

Gas-Gas-LiquidLiquid

Gas-Gas-SolidSolid

30

Triple Point Triple Point — Water— Water

At the At the TRIPLE POINTTRIPLE POINT all all three phases are in three phases are in equilibrium.equilibrium.

31

Phases Phases Diagrams—Diagrams—

Important Points Important Points for Waterfor Water

T(˚C)T(˚C) P(mmHg)P(mmHg)

Normal boil point Normal boil point 100100 760760

Normal freeze pointNormal freeze point 00 760760

Triple point Triple point 0.00980.0098 4.58 4.58

32

Critical T and PCritical T and P

.

LIQUID

GAS

Pcritical

Hig

h P

ress

ure

High Temperature

Tcritical

Note that linegoes straight up

Above critical T Above critical T no liquid exists no liquid exists no matter how no matter how high the high the pressure.pressure.

Above critical T Above critical T no liquid exists no liquid exists no matter how no matter how high the high the pressure.pressure.

As P and T increase, you finally reach the

CRITICAL T and P

33

34

Critical T and PCritical T and P

TTcc((ooC) PC) Pcc(atm) M ((atm) M (g/molg/mol))

HH22OO 374 374 218 (18) P 218 (18) P

Freon-12Freon-12 112112 41 (121) NP 41 (121) NP

(CCl(CCl22FF22))

COCO22 31 31 73 (44) NP 73 (44) NP

CHCH44 -82 -82 46 (16) NP 46 (16) NP

Notice that TNotice that Tcc and P and Pcc depend on depend on

intermolecular forces.intermolecular forces.

35

36

37Phase Diagram for Water

38

Solid-Liquid EquilibriaSolid-Liquid Equilibria

Raising the pressure at constant T causes water to melt.

The NEGATIVE SLOPE of the S/L line is unique to H2O. Almost everything else has positive slope.

SolidH2O

LiquidH2O

P

T

760mmHg

0 ÞC

Normalfreezingpoint

LIQUID H2OICEfavored atlow P

favored athigh P

LIQUID H2OICEfavored atlow P

favored athigh P

INTERMOLECULAR FORCES

STRONG Forces lead to….

Nonvolatile Substances

High boiling points Low evaporation

rates Low vapor P at

room temperature

WEAK Forces lead to..

Volatile substances

Low boiling points High evaporation

rates High vapor P at

room temperature