General Chemistry
Principles and Modern Applications
Petrucci • Harwood • Herring
8 th Edition
Chapter 13: Liquids, Solids and
Intermolecular Forces
Philip Dutton
University of Windsor, Canada
N9B 3P4
Prentice-Hall © 2002
(modified 2003 by Dr. Paul Root and 2005 by Dr. David Tramontozzi)

Contents
13-1 Intermolecular Forces and some Properties of Liquids
13-2 Vaporization of Liquids: Vapor Pressure
13-3 Some Properties of Solids
13-4 Phase Diagrams
13-5 Van der Waals Forces
13-6 Hydrogen Bonding
13-7 Chemical Bonds as Intermolecular Forces
13-8 Crystal structures
13-8 Energy Changes in the Formation of Ionic Crystals
Focus on Liquid Crystals
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 2 of 47

Using the C-C Equation
The vapour pressure of chloroform is 40.0 Torr at -7.1°C. Its enthalpy of vaporization is 29.2 kJ-mol -1 . Calculate its normal boiling point.
We know the C-C equation. This problem becomes placing the values in the proper spots in the equation.
ΔH vap
= 29.2 kJ-mol -1
P
1
= 40.0 Torr
T
1
= -7.1°C = 266 K
P
2
= 760.0 Torr
R = 8.31451 J-K -1 mol -1
P ln = -
P
1
760 ln = -
40.0
ΔH vap
R
29,200
8.31451
1
( -
T
1
1
( -
266
1
T
1
2
T
2
)
)
T
2
= ??
T
2
= 342.3 (about 69°C)
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 3 of 47

13-3 Some Properties of Solids
Cooling Curve Heating Curve
Prentice-Hall © 2002
H
2
O ( s )

H
2
O ( l )
ΔH fus
(H
2
O) = + 6.01 kJ/mol
General Chemistry: Chapter 12 Slide 4 of 47

Prentice-Hall © 2002
Sublimation solid
 vapour equivalent to solid
 liquid followed by liquid  vapour
ΔH sub
=
ΔH fus
+
ΔH vap
= -ΔH deposition
General Chemistry: Chapter 12 Slide 5 of 47

Triple point
13-4 Phase Diagrams
Iodine
Fusion curve
Sublimation curve
Vapor pressure curve
Critical
Point
Different regions correspond to a single phase while lines represent equilibrium between two phases
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 6 of 47

Phase Diagrams
Carbon dioxide
Prentice-Hall © 2002
Conditions in a CO
2 fire extinguisher
Triple point greater than
1 atm so sublimation occurs.
General Chemistry: Chapter 12 Slide 7 of 47

Prentice-Hall © 2002
Supercritical Fluids
General Chemistry: Chapter 12
Remove caffeine from coffee beans using supercritical
CO
2
MeCl
2 rather than
(90°C and
160-220 atm).
When temperature and pressure are reduced, caffeine precipitates.
Slide 8 of 47

The Critical Point
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 9 of 47

Critical Temperatures and Pressures
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 10 of 47

13-5 Van der Waals Forces
•
Instantaneous dipoles.
– Electrons move in an orbital to cause a polarization.
•
Induced dipoles.
– Electrons move in response to an outside force.
Prentice-Hall © 2002
No dipole
Instantaneous dipole
General Chemistry: Chapter 12
Induced dipole
Slide 11 of 47

13-5 Van der Waals Forces
• Dispersion or London forces.
– Instantaneous dipole – induced dipole attraction.
– Related to polarizability (the tendency for charge separation to occur).
– Polarizability increases with the # of electrons and depends on molecular shape.
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 12 of 47

Dipole Dipole Interactions
General Chemistry: Chapter 12
Dipoles tend to arrange themselves with the positive end of one dipole and the negative end of another dipole lining up.
These types of interactions affect physical properties such as melting and boiling points
Slide 13 of 47 Prentice-Hall © 2002

13-6 Hydrogen Bonding
These 3 compounds break the rule that the higher molecular weight, the higher the boiling point
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 14 of 47

Hydrogen Bonding in HF(g)
1. Alignment places a small H atom between two F atoms.
2. H is covalently bonded to one F and weakly bonded to another.
3. Bond angle between F atoms is 180°
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 15 of 47

Hydrogen Bonding in Water
Ice has lower density than water, therefore ice floats. Hbonding holds ice in a rigid but open structure.
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 16 of 47

Other examples of H-Bonds
Intramolecular
H-bond
Dimer formation
Prentice-Hall © 2002 General Chemistry: Chapter 12 Slide 17 of 47