1. To learn about interactions among water molecules
Objectives
To learn about hydrogen bonding, dipole-dipole, and London dispersion forces (van der Waals)
To understand the effect of intermolecular forces on the properties of liquids
To learn about interactions among water molecules
To predict relative physical properties based on intermolecular forces of attraction

2. A. Intermolecular Forces
Reviewing what we know
Gases
Solids
Low density
Highly compressible
Fill container
High density
Slightly compressible
Rigid (keeps its shape)

3. Intermolecular forces – occur between molecules (Red Rover holding hands)
Intramolecular forces – occur inside the molecules (bonds)

4. Occurs between H and highly electronegative atom
Hydrogen Bonding (STRONGEST OF 3) Highly Magnetic Highly Polar Molecule (Not really a Bond) (Adhesion disk demo)
Occurs between H and highly electronegative atom
For example H-N, H-O, H-F bond

5. Dipole – Dipole attraction
(Middle Strength)
Permanent Magnetic Properties related to molecular dipole moment
Polar Molecules

6. London Dispersion Forces (van der Waals)
Weakest-sometimes magnet-NonPolar Molecules Formation of instantaneous dipoles by location of electrons in orbital

7. A. Intermolecular Forces
London Dispersion Forces (van der Waals)
Found in Nonpolar molecules

8. A. Intermolecular Forces
The nature of intermolecular forces is the same as the nature of intramolecular forces (bonds) – only to a varying degree.
Intermolecular forces of attraction are a weaker part of the continuum of magnetic attractive forces that include chemical bonding.
Weaker (Inter) (Intra) Stronger
______________________________________
VDW D-D H-Bond Covalent Polar Ionic

9. A. Intermolecular Forces
H bonding molecules will exhibit all 3 intermolecular forces of attraction
H Bonding forces will be the dominate
D-D molecules will exhibit D-D and vdW
vdW only vdW

10. VDW Dipole – Dipole H-Bonding sometimes Magnet Non Polar Weak IMF
A. Summary of IMF Forces
VDW Dipole – Dipole H-Bonding
sometimes
Magnet
Non Polar
Weak IMF

11. Draw L-D and predict polarity to determine which type of IMF will dominate.
NH3
HCl
BCl3
CH3Cl
CH4
H2O
H2S HF

12. A. Intermolecular Forces
London Dispersion Forces
Become stronger as the sizes of atoms or molecules increase ---WHY?
As atomic size increases, what else increases in number?
How would this affect the ability of the molecules to pull together? FP?

13. A. Intermolecular Forces
Hydrogen Bonding
Affects physical properties
Boiling point
Which molecule has the strongest Intermolecular forces of attraction? Why?

14. A. Intermolecular Forces
Pour CH3OH vs H2O on tabletop
The strength of intermolecular forces of attraction and the ability of the molecules to hold together directly affect the temperature at which substances melt (or freeze) and boil (or condense).
See the Heating Curve…Explain on a molecular level what happens during the solid/liquid and liquid/gas phase change…..

15. B. Water and Its Phase Changes
Heating/cooling curve

16. B. Water and Its Phase Changes
Normal boiling point – at 1 atm = 100oC
Normal freezing point – at 1 atm = 0oC
Density
Liquid = 1.00 g/mL
Solid = g/mL
Density differs because of the H-bonding effect at lower temps (lattice) (vdW, DD, H videos)

17. B. Water and Its Phase Changes
Let’s consider what happens on a molecular level when a substance changes phase from solid to liquid and liquid to gas.
Motion, space between molecules, forces to overcome?
Changes of state video
Thoughts on boiling water at room temperature? Thoughts only!!

18. B. Water and Its Phase Changes
As the strength of the intermolecular forces increases:
The Boiling Point increases
The Vapor Pressure decreases
The Freezing Point increases

19. B. Predicting Relative Physical Properties
Which of the following substances would have the higher boiling point? (Think polarity)
NH3 or BCl3
CH4 or CH3Cl
H2O or H2S
HF or HCl
Which would have the highest freezing point? Vapor Pressure?

20. B. Predicting Relative Physical Properties

23. To learn about interactions among water molecules
Objectives Review
To learn about hydrogen bonding, dipole-dipole, and London dispersion forces (van der Waals)
To understand the effect of intermolecular forces on the properties of liquids
To learn about interactions among water molecules
To predict relative physical properties based on intermolecular forces of attraction
Work Session: Page 497 Review # 1-5

24. To understand and use heat of fusion and heat of vaporization
Objectives
To understand and use heat of fusion and heat of vaporization
To derive formulas
To use the 5 Step Method to find solutions using multiple equations

25. C. Energy Requirements for the Changes of State
Calculate the heat required to raise 9.54 g of liquid water from a temperature of 0 oC to oC? The specific heat capacity of liquid water is
Q = ms T
Q = ?
m = 9.54 g
s = 4.18
T = (80 – 0) oC

26. C. Energy Requirements for the Changes of State
Calculate the heat required to raise 9.54 g of liquid water from a temperature of 0 oC to oC? The specific heat capacity of liquid water is
Q = ms T
Q = (9.54 g) ( )(80 – 0) oC
Q = J = 3.19 kJ
Remember this #

27. C. Energy Requirements for the Changes of State
Changes of state are physical changes
No chemical bonds are broken

28. C. Energy Requirements for the Changes of State
Molar heat of fusion – energy required to melt (S-L) 1 mol of a substance
Molar heat of vaporization – energy required to change 1 mol of a liquid to its vapor …units of both??

29. C. Energy Requirements for the Changes of State
If the molar heat of fusion of ice is 6.02 kJ/mol, how much energy is required to melt 9.54 g of ice at 0 oC?
Can we derive the formula?
Q = (molar heat of fusion kJ/mol)(mol)
Q =
fusion =
mol =

30. If the molar heat of fusion of ice is 6
If the molar heat of fusion of ice is 6.02 kJ/mol, how much energy is required to melt 9.54 g of ice at 0 oC?
Q = (molar heat of fusion kJ/mol)(mol)
Q = ?
fusion = 6.02 kJ/mol
mol = 9.54 g = mol
Q = (6.02 kJ/mol)(0.53mol) = 3.19 kJ
Same Q to change phase S-L as to heat 80 oC!

31. C. Energy Requirements for the Changes of State
Calculate the energy (kJ) required to heat 25 g of liquid water from 25 oC to 100 oC and change it to steam at 100 oC. The specific heat capacity of liquid water is , and the molar heat of vaporization of water is 40.6 kJ/mol.
_____________________________________
Make a mental map- what is the essential Q?
Gather what you know- formulas, constants?
Unit analysis-conceptual logic, what’s going on?

32. C. Energy Requirements for the Changes of State
Calculate the energy (kJ) required to heat 25 g of liquid water from 25 oC to 100 oC and change it to steam at 100 oC. The specific heat capacity of liquid water is , and the molar heat of vaporization of water is 40.6 kJ/mol.
Energy in kJ to take Liq from 25 oC to steam at 100 oC
1) Warm w/o phase change 2) phase change
Two formulas, two thermodynamic properties

33. C. Energy Requirements for the Changes of State
Calculate the energy (kJ) required to heat 25 g of liquid water from 25 oC to 100 oC and change it to steam at 100 oC. The specific heat capacity of liquid water is , and the molar heat of vaporization of water is 40.6 kJ/mol.
1) Warm: Q = ms T
Q =
m =
s =
T =

34. C. Energy Requirements for the Changes of State
1) Warm: Q = ms T
Q = ?
m = 25 g
s = 4.18
T = (100 – 25) oC
Q = ms T = (25 g)( )(75 oC) = 7.8 X 103 J
7800 J = kJ
7.8 kJ Warm only……

35. C. Energy Requirements for the Changes of State
Calculate the energy (kJ) required to heat 25 g of liquid water from 25 oC to 100 oC and change it to steam at 100 oC. The specific heat capacity of liquid water is , and the molar heat of vaporization of water is 40.6 kJ/mol.
2) Phase change
Q = (molar heat of vap kJ/mol)(mol)
Q = ?
vap = 40.6 kJ/mol
mol = 25 g = mol
Q = (40.6 kJ/mol)(1.39 mol) = kJ

36. C. Energy Requirements for the Changes of State
Calculate the energy (kJ) required to heat 25 g of liquid water from 25 oC to 100 oC and change it to steam at 100 oC. The specific heat capacity of liquid water is , and the molar heat of vaporization of water is 40.6 kJ/mol.
1) Warm = 7.8 kJ
2) Phase change = kJ
Total = kJ
Notice that most of the energy is required for the phase change event.

37. C. Energy Requirements for the Changes of State
molar heat of vaporization of water is 40.6 kJ/mol
molar heat of fusion of water is 6.02 kJ/mol
Does it take more energy to melt ice or boil liquid? Why?

38. To understand and use heat of fusion and heat of vaporization
Objectives Review
To understand and use heat of fusion and heat of vaporization
To derive formulas
To use the 5 Step Method to find solutions using multiple equations
Work Session: Page 497 # Practice Problem 14.2

39. To relate the boiling point of water to its vapor pressure
Objectives
To understand the relationship among vaporization, condensation and vapor pressure
To relate the boiling point of water to its vapor pressure
To predict relative physical properties based on intermolecular forces of attraction

40. A. Evaporation and Vapor Pressure
Vaporization or evaporation – individual molecules gain enough energy to change phase
Endothermic – requires heat input (Sanitizer)

41. A. Evaporation and Vapor Pressure
Amount of liquid first decreases then becomes constant - H2O bottle
Condensation - process by which vapor molecules convert to a liquid
When no further change is visible the opposing processes balance each other - equilibrium

42. A. Evaporation and Vapor Pressure
Vapor pressure - pressure of the vapor present at equilibrium with its liquid
Vapor pressures vary widely - relates to intermolecular forces

43. A. Evaporation and Vapor Pressure
Vapor pressure - pressure of the vapor present at equilibrium with its liquid- relates to intermolecular forces
Molecules with higher intermolecular forces of attraction will have ________ vapor pressures because _________________________.
lower, molecules will hold together more.

44. A. Evaporation and Vapor Pressure
Which of the following substances would have the higher vapor pressure? Why?
NH3 or BF3
CH4 or CH2Cl2
H2O or CH3OH (methyl alcohol)
CH3OH or CH3CH2CH2CH2OH (butyl alc)
What is the BP of methyl alcohol? Butyl alc?

45. B. Boiling Point and Vapor Pressure

46. B. Boiling Point and Vapor Pressure

47. B. Boiling Point and Vapor Pressure
Boiling point is defined as occurring when the vapor pressure of the liquid is equal to the total external pressure (atmospheric pressure). Not defined by temperature!
Boil water at room temp??
Boil water with ice?

48. B. Boiling Point and Vapor Pressure
Which of the following substances would have the higher……BP FP VP
GeH4 or AsH3
CCl4 or H2Te
CO2 or H2S
HF or HBr
The amazing floating steel!

49. To relate the boiling point of water to its vapor pressure
Objectives Review
To understand the relationship among vaporization, condensation and vapor pressure
To relate the boiling point of water to its vapor pressure
To predict relative physical properties based on IMF’s
To reiterate the difference between IMF and bonds
Work Session: Page 503 # 1, 2, 4, 5, 6

50. To learn about the types of crystalline solids
Objectives
To learn about the types of crystalline solids
To understand the interparticle forces in crystalline solids
To learn how the bonding in metals determines metallic properties

51. A. The Solid State: Types of Solids
Crystalline solids

52. A. The Solid State: Types of Solids

53. A. The Solid State: Types of Solids

54. B. Bonding in Solids

55. B. Bonding in Solids
Ionic Solids
Stable substances with high melting points
Held together by strong forces between ions

56. B. Bonding in Solids
Molecular Solids
Fundamental particle is a molecule
Melt at relatively low temperatures
Held together by weak intermolecular forces

57. B. Bonding in Solids
Atomic Solids
Fundamental particle is the atom
Properties vary greatly
Group 8 - low melting points
Diamond - very high melting point

58. B. Bonding in Solids
Bonding in Metals
Metals are held together by nondirectional covalent bonds (called the electron sea model) among the closely packed atoms
Video clips?

59. B. Bonding in Solids
Bonding in Metals
Metals form alloys of two types
Substitutional – different atoms are substituted for the host metal atoms

60. B. Bonding in Solids
Bonding in Metals
Metals form alloys of two types
Interstitial – small atoms are introduced into the “holes” in the metallic structure