___________________________________ Slide 1 ___________________________________ ___________________________________ Chapter 14
___________________________________ Liquids and Solids
___________________________________ ___________________________________ ___________________________________ Slide Chapter 14
2 Table of Contents
14.1
14.2
14.3
14.4
14.5
14.6
___________________________________ ___________________________________ Water and Its Phase Changes
Energy Requirements for the Changes of State
Intermolecular Forces
Evaporation and Vapor Pressure
The Solid State: Types of Solids
Bonding in Solids
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___________________________________ Slide Section 14.1
3 Water and Its Phase Changes
___________________________________ Reviewing What We Know
•
Gases
 Low density
 Highly compressible
 Fill container
• Solids
 High density
 Slightly compressible
 Rigid (keeps its shape)
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Slide Section 14.1
4 Water and Its Phase Changes
___________________________________ ___________________________________ Heating/Cooling Curve
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Slide Section 14.1
5 Water and Its Phase Changes
4
___________________________________ ___________________________________ Heating/Cooling Curve
• Normal boiling point: at 1 atm = 100°C
• Normal freezing point: at 1 atm = 0°C
• Density
 Liquid water = 1.00 g/mL
 Ice = 0.917 g/mL
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Slide Section 14.1
6 Water and Its Phase Changes
5
___________________________________ ___________________________________ Concept Check
___________________________________ During the process of melting ice by adding
heat, the temperature of the ice/liquid water
slurry
a)
b)
c)
d)
___________________________________ ___________________________________ stays constant.
increases.
decreases.
cannot be predicted.
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Slide Section 14.2
7 Energy Requirements for the Changes of State
___________________________________ ___________________________________ •
Changes of state are
physical changes.
 No chemical bonds
are broken.
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Slide Section 14.2
8 Energy Requirements for the Changes of State
7
___________________________________ ___________________________________ Phase Changes
• When a substance changes from solid to liquid
to gas, the molecules remain intact.
• The changes in state are due to changes in the
forces among molecules rather than in those
within the molecules.
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Slide Section 14.2
9 Energy Requirements for the Changes of State
8
___________________________________ ___________________________________ Phase Changes
• Solid to Liquid
 As energy is added, the motions of the
molecules increase, and they eventually
achieve the greater movement and disorder
characteristic of a liquid.
• Liquid to Gas
 As more energy is added, the gaseous state
is eventually reached, with the individual
molecules far apart and interacting relatively
little.
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Slide Section 14.2
10 Energy Requirements for the Changes of State
___________________________________ ___________________________________ Intramolecular Forces
• “Within” the molecule.
• Molecules are formed by sharing electrons
between the atoms.
• Hold the atoms of a molecule together.
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Slide Section 14.2
11 Energy Requirements for the Changes of State
10
___________________________________ ___________________________________ Intermolecular Forces
• Forces that occur between molecules.
___________________________________ ___________________________________ ___________________________________ ___________________________________ • Intramolecular bonds are stronger than
intermolecular forces.
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Slide Section 14.2
12 Energy Requirements for the Changes of State
11
___________________________________ ___________________________________ • Molar heat of fusion – energy required to melt 1
mol of a substance.
• Molar heat of vaporization – energy required to
change 1 mol of a liquid to its vapor.
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___________________________________ Slide Section 14.2
13 Energy Requirements for the Changes of State
___________________________________ Concept Check
___________________________________ Which are stronger, intramolecular bonds or
intermolecular forces?
___________________________________ How do you know?
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___________________________________ Slide Section 14.2
14 Energy Requirements for the Changes of State
___________________________________ Concept Check
___________________________________ Which would you predict should be larger for
a given substance: Hvap or Hfus?
___________________________________ Explain why.
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___________________________________ Slide Section 14.2
15 Energy Requirements for the Changes of State
___________________________________ Concept Check
___________________________________ The unusually high value of the molar heat of vaporization of
water (40.6 kJ/mole) is an important factor in moderating the
temperature of the earth’s surface, and results in an enormous
transfer of energy to the atmosphere as liquid water evaporates
as part of the hydrologic cycle. Calculate the amount of heat in
kJ needed to evaporate 10.5 kg of liquid water at 100.oC.
a)
b)
c)
d)
___________________________________ ___________________________________ 4.27 × 105 kJ
3.15 × 104 kJ
2.37 × 104 kJ
1.18 × 103 kJ
10.5 kg H2O 
___________________________________ 1 mol H2O
1000 g
40.6 kJ


 2.37  104 kJ
1 kg
18.016 g H2O
mol
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Slide Section 14.3
16 Intermolecular Forces
___________________________________ ___________________________________ • Forces that occur between molecules.
 Dipole–dipole forces
___________________________________  Hydrogen bonding
___________________________________  London dispersion forces
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Slide Section 14.3
17 Intermolecular Forces
16
___________________________________ ___________________________________ Dipole–Dipole Attraction
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Slide Section 14.3
18 Intermolecular Forces
17
___________________________________ ___________________________________ Dipole-Dipole Forces
• Dipole moment – molecules with polar bonds
often behave in an electric field as if they had a
center of positive charge and a center of
negative charge.
• Molecules with dipole moments can attract each
other electrostatically. They line up so that the
positive and negative ends are close to each
other.
• Only about 1% as strong as covalent or ionic
bonds.
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Slide Section 14.3
19 Intermolecular Forces
___________________________________ ___________________________________ Hydrogen Bonding
• Strong dipole-dipole forces.
• Hydrogen is bound to a highly electronegative
atom – nitrogen, oxygen, or fluorine.
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Slide Section 14.3
20 Intermolecular Forces
19
___________________________________ ___________________________________ Hydrogen Bonding in Water
• Blue dotted lines are
the intermolecular
forces between the
water molecules.
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Slide Section 14.3
21 Intermolecular Forces
20
___________________________________ ___________________________________ Hydrogen Bonding
• Affects physical properties
 Boiling point
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Slide Section 14.3
22 Intermolecular Forces
___________________________________ ___________________________________ London Dispersion Forces
• Instantaneous dipole that occurs accidentally in
a given atom induces a similar dipole in a
neighboring atom.
• Significant in large atoms/molecules.
• Occurs in all molecules, including nonpolar
ones.
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Slide Section 14.3
23 Intermolecular Forces
22
___________________________________ ___________________________________ London Dispersion Forces – Nonpolar Molecules
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Slide Section 14.3
24 Intermolecular Forces
23
___________________________________ ___________________________________ London Dispersion Forces
• Become stronger as
the sizes of atoms or
molecules increase.
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___________________________________ Slide Section 14.3
25 Intermolecular Forces
___________________________________ Melting and Boiling Points
• In general, the stronger the intermolecular
forces, the higher the melting and boiling points.
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___________________________________ Slide Section 14.3
26 Intermolecular Forces
___________________________________ Concept Check
___________________________________ Which molecule is capable of forming
stronger intermolecular forces?
N2
___________________________________ H 2O
___________________________________ Explain.
___________________________________ ___________________________________ Return to TOC
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Slide Section 14.3
27 Intermolecular Forces
26
___________________________________ ___________________________________ Concept Check
___________________________________ Draw two Lewis structures for the formula
C2H6O and compare the boiling points of the
two molecules.
H H
H C C O H
H H
H
H C O
H
___________________________________ ___________________________________ H
C H
___________________________________ H
___________________________________ Return to TOC
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___________________________________ Slide Section 14.3
28 Intermolecular Forces
___________________________________ Concept Check
___________________________________ Which gas would behave more ideally at the
same conditions of P and T?
CO
or
___________________________________ N2
___________________________________ Why?
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Slide Section 14.3
29 Intermolecular Forces
28
___________________________________ ___________________________________ Concept Check
___________________________________ Consider the following compounds:
CH4
H2
NH3
___________________________________ How many of the compounds above exhibit London
dispersion forces?
a)
b)
c)
d)
0
1
2
3
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Slide Section 14.4
30 Evaporation and Vapor Pressure
___________________________________ ___________________________________ ___________________________________ Return to TOC
29
___________________________________ ___________________________________ Vaporization or Evaporation
• Molecules of a liquid can escape the liquid’s
surface and form a gas.
• Endothermic process – requires energy to
overcome the relatively strong intermolecular
forces in the liquid.
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___________________________________ Slide Section 14.4
31 Evaporation and Vapor Pressure
___________________________________ Vapor Pressure
•
•
•
Amount of liquid first decreases then becomes constant.
Condensation - process by which vapor molecules
convert to a liquid.
When no further change is visible the opposing
processes balance each other – equilibrium
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___________________________________ Slide Section 14.4
32 Evaporation and Vapor Pressure
___________________________________ Vapor Pressure
• Pressure of the vapor present at equilibrium.
• The system is at equilibrium when no net
change occurs in the amount of liquid or vapor
because the two opposite processes exactly
balance each other.
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___________________________________ Slide Section 14.4
33 Evaporation and Vapor Pressure
___________________________________ Concept Check
___________________________________ What is the vapor pressure of water at
100°C? How do you know?
___________________________________ 1 atm
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Slide Section 14.4
34 Evaporation and Vapor Pressure
___________________________________ ___________________________________ Vapor Pressure
• Liquids in which the intermolecular forces are
strong have relatively low vapor pressures.
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Slide Section 14.4
35 Evaporation and Vapor Pressure
34
___________________________________ ___________________________________ Concept Check
___________________________________ Which of the following would be expected to
have the highest vapor pressure at room
temperature?
a)
b)
c)
d)
___________________________________ ___________________________________ CH3CH2CH2OH
CH3CH2CH2NH2
CH3CH2CH2CH3
CH3CH2CH3
___________________________________ ___________________________________ Return to TOC
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Slide Section 14.5
36 The Solid State: Types of Solids
35
___________________________________ ___________________________________ Crystalline Solids
• Regular arrangement of their components.
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Slide Section 14.5
37 The Solid State: Types of Solids
___________________________________ ___________________________________ Types of Crystalline Solids
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Slide Section 14.5
38 The Solid State: Types of Solids
37
___________________________________ ___________________________________ Types of Crystalline Solids
• Ionic Solids – ions at the points of the lattice
that describes the structure of the solid.
• Molecular Solids – discrete covalently bonded
molecules at each of its lattice points.
• Atomic Solids – atoms at the lattice points that
describe the structure of the solid.
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Slide Section 14.5
39 The Solid State: Types of Solids
38
___________________________________ ___________________________________ Examples of Three Types of Crystalline Solids
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Slide Section 14.6
40 Bonding in Solids
___________________________________ ___________________________________ Examples of the Various Types of Solids
___________________________________ ___________________________________ ___________________________________ ___________________________________ ___________________________________ Return to TOC
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Slide Section 14.6
41 Bonding in Solids
40
___________________________________ ___________________________________ Ionic Solids
• Stable substances with high melting points.
• Held together by strong forces between ions.
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Slide Section 14.6
42 Bonding in Solids
41
___________________________________ ___________________________________ Molecular Solids
• Fundamental particle is a molecule.
• Melt at relatively low temperatures.
• Held together by weak intermolecular forces.
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Slide Section 14.6
43 Bonding in Solids
___________________________________ ___________________________________ Atomic Solids
• Fundamental particle is the atom.
• Properties vary greatly.
 Group 8 – low melting points
 Diamond – very high melting point
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Slide Section 14.6
44 Bonding in Solids
43
___________________________________ ___________________________________ Bonding in Metals
• Metals are held together by nondirectional
covalent bonds (called the electron sea model)
among the closely packed atoms.
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Slide Section 14.6
45 Bonding in Solids
44
___________________________________ ___________________________________ Bonding in Metals
• Metals form alloys of two types.
___________________________________  Substitutional – different atoms are substituted for
the host metal atoms.
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Slide Section 14.6
46 Bonding in Solids
___________________________________ ___________________________________ Bonding in Metals
• Metals form alloys of two types.
___________________________________  Interstitial – small atoms are introduced into the
“holes” in the metallic structure.
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Slide 47 46
___________________________________ Section 14.6
Chapter
14 Homework
Bonding
in Solids
___________________________________ Homework
___________________________________ • Reading assignment
– Pages 447 through 467
___________________________________ • Homework Problems
– Questions and problems 9, 11, 21, 23, 27, 29, 33, 37,
45, 49.
___________________________________ ___________________________________ • Due on
___________________________________ Return to TOC
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