The document discusses intermolecular forces, the different types of intermolecular forces (dipole-dipole, ion-dipole, dispersion), and hydrogen bonding. It also covers properties of liquids related to intermolecular forces like surface tension, viscosity, and water's unusual properties. Finally, it discusses phases of matter, phase transitions, vapor pressure, boiling/melting points, and heat effects of phase changes.

1. Intermolecular Forces and
Liquids and Solids
Chapter 11
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2. A phase is a homogeneous part of the system in
contact with other parts of the system but
separated from them by a well-defined boundary.
2 Phases
Solid phase - ice
Liquid phase - water
11.1

3. Intermolecular Forces
Intermolecular forces are attractive forces between molecules.
Intramolecular forces hold atoms together in a molecule.
Intermolecular vs Intramolecular
• 41 kJ to vaporize 1 mole of water (inter)
• 930 kJ to break all O-H bonds in 1 mole of water (intra)
“Measure” of intermolecular force
Generally,
boiling point
intermolecular
forces are much melting point
weaker than ∆Hvap
intramolecular
∆Hfus
forces.
∆Hsub 11.2

4. Intermolecular Forces
Dipole-Dipole Forces
Attractive forces between polar molecules
Orientation of Polar Molecules in a Solid
11.2

5. Intermolecular Forces
Ion-Dipole Forces
Attractive forces between an ion and a polar molecule
Ion-Dipole Interaction
11.2

6. 11.2

7. Intermolecular Forces
Dispersion Forces
Attractive forces that arise as a result of temporary
dipoles induced in atoms or molecules
ion-induced dipole interaction
dipole-induced dipole interaction
11.2

8. Induced Dipoles Interacting With Each Other
11.2

9. Intermolecular Forces
Dispersion Forces Continued
Polarizability is the ease with which the electron distribution
in the atom or molecule can be distorted.
Polarizability increases with:
• greater number of electrons
• more diffuse electron cloud
Dispersion
forces usually
increase with
molar mass.
11.2

10. What type(s) of intermolecular forces exist between
each of the following molecules?
HBr
HBr is a polar molecule: dipole-dipole forces. There are
also dispersion forces between HBr molecules.
CH4
CH4 is nonpolar: dispersion forces.
S O
SO2 O
SO2 is a polar molecule: dipole-dipole forces. There are
also dispersion forces between SO2 molecules.
11.2

11. Intermolecular Forces
Hydrogen Bond
The hydrogen bond is a special dipole-dipole interaction
between they hydrogen atom in a polar N-H, O-H, or F-H bond
and an electronegative O, N, or F atom.
A H…B or A H…A
A & B are N, O, or F
11.2

12. Hydrogen Bond
11.2

13. Why is the hydrogen bond considered a
“special” dipole-dipole interaction?
Decreasing molar mass
Decreasing boiling point
11.2

14. Properties of Liquids
Surface tension is the amount of energy required to stretch
or increase the surface of a liquid by a unit area.
Strong
intermolecular
forces
High
surface
tension
11.3

15. Properties of Liquids
Cohesion is the intermolecular attraction between like molecules
Adhesion is an attraction between unlike molecules
Adhesion
Cohesion
11.3

16. Properties of Liquids
Viscosity is a measure of a fluid’s resistance to flow.
Strong
intermolecular
forces
High
viscosity
11.3

17. Water is a Unique Substance
Maximum Density
40C
Density of Water
Ice is less dense than water
11.3

18. Types of Crystals
Covalent Crystals
• Lattice points occupied by atoms
• Held together by covalent bonds
• Hard, high melting point
• Poor conductor of heat and electricity
carbon
atoms
diamond graphite 11.6

19. Types of Crystals
Metallic Crystals
• Lattice points occupied by metal atoms
• Held together by metallic bonds
• Soft to hard, low to high melting point
• Good conductors of heat and electricity
Cross Section of a Metallic Crystal
nucleus &
inner shell e-
mobile “sea”
of e-
11.6

20. Crystal Structures of Metals
11.6

21. Types of Crystals
11.6

22. Chemistry In Action: High-Temperature Superconductors

23. Least
Order
Condensation
Evaporation Greatest
Order
T2 > T1
11.8

24. The equilibrium vapor pressure is the vapor pressure
measured when a dynamic equilibrium exists between
condensation and evaporation
H2O (l) H2O (g)
Dynamic Equilibrium
Rate of Rate of
condensation
= evaporation
11.8

25. Before At
Evaporation Equilibrium
11.8

26. The boiling point is the temperature at which the
(equilibrium) vapor pressure of a liquid is equal to the
external pressure.
The normal boiling point is the temperature at which a liquid
boils when the external pressure is 1 atm.
11.8

27. H2O (s) H2O (l)
The melting point of a solid
or the freezing point of a
liquid is the temperature at
which the solid and liquid
Freezing
Melting
phases coexist in equilibrium
11.8

28. Molar heat of fusion (∆Hfus) is the energy required to melt
1 mole of a solid substance at its freezing point.
11.8

29. Heating Curve
11.8