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Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All...

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Chapter 14 Liquids and Solids
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Page 1: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Chapter 14

Liquids and Solids

Page 2: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Chapter 14

Table of Contents

Copyright © Cengage Learning. All rights reserved 2

14.1 Water and Its Phase Changes

14.2 Energy Requirements for the Changes of State

14.3 Intermolecular Forces

14.4 Evaporation and Vapor Pressure

14.5 The Solid State: Types of Solids

14.6 Bonding in Solids

Page 3: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.1

Water and Its Phase Changes

Return to TOC

Copyright © Cengage Learning. All rights reserved 3

Reviewing What We Know

• Gases Low density Highly compressible Fill container

• Solids High density Slightly compressible Rigid (keeps its shape)

Page 4: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.1

Water and Its Phase Changes

Return to TOC

Copyright © Cengage Learning. All rights reserved 4

Heating/Cooling Curve

Page 5: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.1

Water and Its Phase Changes

Return to TOC

Copyright © Cengage Learning. All rights reserved 5

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

Page 6: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.1

Water and Its Phase Changes

Return to TOC

Copyright © Cengage Learning. All rights reserved 6

Concept Check

During the process of melting ice by adding heat, the temperature of the ice/liquid water slurry

a) stays constant.b) increases.c) decreases.d) cannot be predicted.

Page 7: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Energy Requirements for the Changes of State

Section 14.2

Return to TOC

Copyright © Cengage Learning. All rights reserved 7

• Changes of state are physical changes. No chemical bonds

are broken.

Page 8: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Energy Requirements for the Changes of State

Section 14.2

Return to TOC

Copyright © Cengage Learning. All rights reserved 8

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.

Page 9: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Energy Requirements for the Changes of State

Section 14.2

Return to TOC

Copyright © Cengage Learning. All rights reserved 9

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.

Page 10: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Energy Requirements for the Changes of State

Section 14.2

Return to TOC

Copyright © Cengage Learning. All rights reserved 10

Intramolecular Forces

• “Within” the molecule.• Molecules are formed by sharing electrons

between the atoms.• Hold the atoms of a molecule together.

Page 11: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Energy Requirements for the Changes of State

Section 14.2

Return to TOC

Copyright © Cengage Learning. All rights reserved 11

Intermolecular Forces

• Forces that occur between molecules.

• Intramolecular bonds are stronger than intermolecular forces.

Page 12: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Energy Requirements for the Changes of State

Section 14.2

Return to TOC

Copyright © Cengage Learning. All rights reserved 12

• 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.

Page 13: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Energy Requirements for the Changes of State

Section 14.2

Return to TOC

Copyright © Cengage Learning. All rights reserved 13

Concept Check

Which are stronger, intramolecular bonds or intermolecular forces?

How do you know?

Page 14: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Energy Requirements for the Changes of State

Section 14.2

Return to TOC

Copyright © Cengage Learning. All rights reserved 14

Concept Check

Which would you predict should be larger for a given substance: Hvap or Hfus?

Explain why.

Page 15: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Energy Requirements for the Changes of State

Section 14.2

Return to TOC

Copyright © Cengage Learning. All rights reserved 15

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) 4.27 × 105 kJb) 3.15 × 104 kJc) 2.37 × 104 kJd) 1.18 × 103 kJ

422

2

1 mol H O1000 g 40.6 kJ10.5 kg H O 2.37 10 kJ

1 kg 18.016 g H O mol

Page 16: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 16

• Forces that occur between molecules. Dipole–dipole forces

Hydrogen bonding London dispersion forces

Page 17: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 17

Dipole–Dipole Attraction

Page 18: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 18

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.

Page 19: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 19

Hydrogen Bonding

• Strong dipole-dipole forces.• Hydrogen is bound to a highly electronegative

atom – nitrogen, oxygen, or fluorine.

Page 20: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 20

Hydrogen Bonding in Water

• Blue dotted lines are the intermolecular forces between the water molecules.

Page 21: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 21

Hydrogen Bonding

• Affects physical properties Boiling point

Page 22: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 22

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.

Page 23: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 23

London Dispersion Forces – Nonpolar Molecules

Page 24: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 24

London Dispersion Forces

• Become stronger as the sizes of atoms or molecules increase.

Page 25: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 25

Melting and Boiling Points

• In general, the stronger the intermolecular forces, the higher the melting and boiling points.

Page 26: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 26

Concept Check

Which molecule is capable of forming stronger intermolecular forces?

N2 H2O

Explain.

Page 27: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 27

Concept Check

Draw two Lewis structures for the formula C2H6O and compare the boiling points of the two molecules.

C

H

H C

H

H

H

O H C

H

H C

H

H

H

O H

Page 28: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 28

Concept Check

Which gas would behave more ideally at the same conditions of P and T?

CO or N2

Why?

Page 29: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Intermolecular Forces

Section 14.3

Return to TOC

Copyright © Cengage Learning. All rights reserved 29

Concept Check

Consider the following compounds:

NH3 CH4 H2

How many of the compounds above exhibit London dispersion forces?

a) 0

b) 1

c) 2

d) 3

Page 30: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.4

Evaporation and Vapor Pressure

Return to TOC

Copyright © Cengage Learning. All rights reserved 30

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.

Page 31: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.4

Evaporation and Vapor Pressure

Return to TOC

Copyright © Cengage Learning. All rights reserved 31

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

Page 32: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.4

Evaporation and Vapor Pressure

Return to TOC

Copyright © Cengage Learning. All rights reserved 32

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.

Page 33: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.4

Evaporation and Vapor Pressure

Return to TOC

Copyright © Cengage Learning. All rights reserved 33

Concept Check

What is the vapor pressure of water at 100°C? How do you know?

1 atm

Page 34: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.4

Evaporation and Vapor Pressure

Return to TOC

Copyright © Cengage Learning. All rights reserved 34

Vapor Pressure

• Liquids in which the intermolecular forces are strong have relatively low vapor pressures.

Page 35: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.4

Evaporation and Vapor Pressure

Return to TOC

Copyright © Cengage Learning. All rights reserved 35

Concept Check

Which of the following would be expected to have the highest vapor pressure at room temperature?

a) CH3CH2CH2OHb) CH3CH2CH2NH2

c) CH3CH2CH2CH3

d) CH3CH2CH3

Page 36: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.5

The Solid State: Types of Solids

Return to TOC

Copyright © Cengage Learning. All rights reserved 36

Crystalline Solids

• Regular arrangement of their components.

Page 37: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.5

The Solid State: Types of Solids

Return to TOC

Copyright © Cengage Learning. All rights reserved 37

Types of Crystalline Solids

Page 38: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.5

The Solid State: Types of Solids

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Copyright © Cengage Learning. All rights reserved 38

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.

Page 39: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.5

The Solid State: Types of Solids

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Copyright © Cengage Learning. All rights reserved 39

Examples of Three Types of Crystalline Solids

Page 40: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.6

Bonding in Solids

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Copyright © Cengage Learning. All rights reserved 40

Examples of the Various Types of Solids

Page 41: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.6

Bonding in Solids

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Copyright © Cengage Learning. All rights reserved 41

Ionic Solids

• Stable substances with high melting points. • Held together by strong forces between ions.

Page 42: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.6

Bonding in Solids

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Copyright © Cengage Learning. All rights reserved 42

Molecular Solids

• Fundamental particle is a molecule. • Melt at relatively low temperatures. • Held together by weak intermolecular forces.

Page 43: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.6

Bonding in Solids

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Copyright © Cengage Learning. All rights reserved 43

Atomic Solids

• Fundamental particle is the atom. • Properties vary greatly.

Group 8 – low melting points Diamond – very high melting point

Page 44: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.6

Bonding in Solids

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Copyright © Cengage Learning. All rights reserved 44

Bonding in Metals

• Metals are held together by nondirectional covalent bonds (called the electron sea model) among the closely packed atoms.

Page 45: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.6

Bonding in Solids

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Copyright © Cengage Learning. All rights reserved 45

Bonding in Metals

• Metals form alloys of two types. Substitutional – different atoms are substituted for

the host metal atoms.

Page 46: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.6

Bonding in Solids

Return to TOC

Copyright © Cengage Learning. All rights reserved 46

Bonding in Metals

• Metals form alloys of two types. Interstitial – small atoms are introduced into the

“holes” in the metallic structure.

Page 47: Chapter 14 Liquids and Solids. Chapter 14 Table of Contents Copyright © Cengage Learning. All rights reserved 2 14.1 Water and Its Phase Changes 14.2.

Section 14.6

Bonding in Solids

Return to TOC

Copyright © Cengage Learning. All rights reserved 47Copyright © Cengage Learning. All rights reserved 47

Homework

• Reading assignment– Pages 447 through 467

• Homework Problems– Questions and problems 9, 11, 21, 23, 27, 29, 33, 37,

45, 49.

• Due on

Chapter 14 Homework


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