11.5 Vapor Pressure• Explaining Vapor Pressure on the Molecular Level, Volatility, • Vapor Pressure, and Temperature; • Vapor Pressure and Boiling Point

11.6 Phase Diagrams• The Phase Diagrams of H2O and CO2

11.7 Structures of Solids• Unit Cells• The Crystal Structure of Sodium Chloride• Close Packing of Spheres

11.8 Bonding in Solids• Molecular Solids• Covalent-Network Solids• Ionic Solids• Metallic Solids

Chapter 13 Properties of Solutions13.1 The Solution Process

• Energy Changes and Solution Formation• Solution Formation, Spontaneity, and Disorder• Solution Formation and Chemical Reactions

The observation of Vapor Pressure:

And, at higher temperatures, the vp is higher.

The samepicture isuseful torationalizeVapor Pressure

With the beaker covered, equilibrium issoon established.

Contrast that with an uncovered beaker!

(Add slide of C-C eq and plot.)

But, recall, we always prefer straight lines!

ln PH

R TCvap

vap

1

← Temp. increases

O r w ith P the vapor pressu re a t T and P the vapor pressu re a t T

PH

R TC and P

H

R TC

sub trac t to g ive

P PH

R T T

or

P

P

H

R T T

vap vap

vap

vap

,

ln ln

ln ln

ln

1 1 2 2

22

11

2 11 2

2

1 1 2

1 1

1 1

1 1

Using the Clausius-Clapeyron Equation:

Tabulate P in atm and T in K; Calculate lnP and 1/TPlot lnP vs 1/T

The slope is = - ΔHvap /R

The slope!

The quiz next week will be given during your recitation.

It will cover material starting with section11.5.

First Midquarter ExamMonday, Jan 31

6:30-7:48 pmRooms TBA

Chaps 10, 11, 13

11.51 The normal melting and boiling points of xenon are -112 oC and -107 oC, respectively. Its triple point is at-121 oC and 282 torr, and its critical point is a 16.6 oCand 57.6 atm.

(a) Sketch the phase diagram of Xe, showing the fourpoints given above and indicating the area in which each phase is stable.

(b) Which is more dense, solid or liquid Xe?

(c) If Xe gas is cooled under an external pressure of 100 torr, will it undergo condensation or deposition?

11.7 Structures of Solids• Unit Cells• The Crystal Structure of NaCl• Close Packing of Spheres

11.8 Bonding in Solids• Molecular Solids• Covalent-Network Solids• Ionic Solids• Metallic Solids

Sulfur Crystals

Millerite Crystals (a nickel ore)

These are the ones we’ll beinterested in.

↓

The ‘NaCl’ Structure

Hexagonalclosepacking(ABABAB…)

Cubicclosepacking(ABCABC..)

fact

11.7 Structures of Solids• Unit Cells• The Crystal Structure of NaCl• Close Packing of Spheres

11.8 Bonding in Solids• Molecular Solids• Covalent-Network Solids• Ionic Solids• Metallic Solids

Contrast the MPs and BPs of some materials which are Molecular Solids:

C6H6 C6H5-CH3 C6H5-OH

MP 5 -95 43

BP 80 111 182

11.59 Aluminum metal crystallizes in a cubic close-packedstructure (face-centered cubic cell).

(a) How many aluminum atoms are in a unit cell?

(b) What is the coordination number of each aluminum atom?

(c) Assume that the aluminum catoms can be represented as spheres. If each Al atom has a radius of 1.43 Å, what is the length of a side of the unit cell?

(d) Calculate the density of Al metal.

11.67 A certain form of AgI adopts the zinc blende structure.The density of the salt is 5.69 g/cm3.

(a) Calculate the length of a side of the unit cell.

(b) Calculate the distance between the Ag+ and I- ions in the structure.

At wt Ag = 107.9 I = 126.9

No = 6.02 x 1023 amu/g 1 Å = 10-8 cm

11.32 The heat of vaporization of CCl2F2 (a CFC) is 289 J/g. What mass of this substance must evaporate in order to freeze 100 g of water initially at 18 oC?

(The heat of fusion of water is 334 J/g and the specificheat of liquid water is 4.18 J/g-K)