Download - I. Intermolecular Forces
![Page 1: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/1.jpg)
Ch. 12 – States of MatterCh. 12 – States of MatterCh. 12 – States of MatterCh. 12 – States of Matter
I. Intermolecular ForcesI. Intermolecular Forces
![Page 2: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/2.jpg)
A. Definition of IMFA. Definition of IMF
Attractive forces between molecules.
Much weaker than chemical bonds within molecules.
a.k.a. van der Waals forces
![Page 3: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/3.jpg)
C. Johannesson
B. Types of IMFB. Types of IMF
![Page 4: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/4.jpg)
B. Types of IMFB. Types of IMF
London Dispersion Forces
View animation online.
![Page 5: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/5.jpg)
B. Types of IMFB. Types of IMF
Dipole-Dipole Forces
+ -
View animation online.
![Page 6: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/6.jpg)
B. Types of IMFB. Types of IMF
Hydrogen Bonding
![Page 7: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/7.jpg)
C. Determining IMFC. Determining IMF
NCl3• polar = dispersion, dipole-dipole
CH4
• nonpolar = dispersionHF
• H-F bond = dispersion, dipole-dipole, hydrogen bonding
![Page 8: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/8.jpg)
II. Physical PropertiesII. Physical Properties
Ch. 12 - Liquids & SolidsCh. 12 - Liquids & SolidsCh. 12 - Liquids & SolidsCh. 12 - Liquids & Solids
![Page 9: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/9.jpg)
A. Liquids vs. SolidsA. Liquids vs. Solids
LIQUIDS
Stronger than in gases
Y
high
N
slower than in gases
SOLIDS
Very strong
N
high
N
extremely slow
IMF Strength
Fluid
Density
Compressible
Diffusion
![Page 10: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/10.jpg)
B. Liquid PropertiesB. Liquid Properties
Surface Tension• attractive force between particles in a
liquid that minimizes surface area
![Page 11: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/11.jpg)
B. Liquid PropertiesB. Liquid Properties
Capillary Action• attractive force between the surface of
a liquid and the surface of a solid
![Page 12: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/12.jpg)
B. Liquid PropertiesB. Liquid Properties
Viscosity• Measure of the resistance of a liquid to
flow
![Page 13: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/13.jpg)
B. Liquid PropertiesB. Liquid Properties
Cohesion• Force of attraction between
identical moleculesAdhesion
• Force of attraction
between different
molecules water mercury
![Page 14: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/14.jpg)
C. Types of SolidsC. Types of Solids
Crystalline - repeating geometric pattern• covalent network• metallic• ionic• covalent molecular
Amorphous - no geometric pattern
decreasingm.p.
![Page 15: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/15.jpg)
C. Types of SolidsC. Types of Solids
Ionic(NaCl)
Metallic
![Page 16: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/16.jpg)
C. Types of SolidsC. Types of Solids
CovalentMolecular
(H2O)
CovalentNetwork
(SiO2 - quartz)
Amorphous(SiO2 - glass)
![Page 17: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/17.jpg)
C. Types of SolidsC. Types of Solids
Allotrope• In a covalent network, different forms in the same
state
Carbon
allotropeswater mercury
![Page 18: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/18.jpg)
C. Types of SolidsC. Types of Solids
Amorphous Solid• No geometric pattern
water mercury
![Page 19: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/19.jpg)
Ch. 12 - Liquids & SolidsCh. 12 - Liquids & SolidsCh. 12 - Liquids & SolidsCh. 12 - Liquids & Solids
III. Changes of StateIII. Changes of State
![Page 20: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/20.jpg)
A. Phase ChangesA. Phase Changes
![Page 21: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/21.jpg)
A. Phase ChangesA. Phase Changes
EvaporationEvaporation• molecules at the surface gain enough
energy to overcome IMF
VolatilityVolatility• measure of evaporation rate• depends on temp & IMF
![Page 22: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/22.jpg)
A. Phase ChangesA. Phase Changes
Kinetic Energy
# o
f P
art
icle
s
Boltzmann Distribution
temp
volatility
IMF
volatility
![Page 23: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/23.jpg)
A. Phase ChangesA. Phase Changes
EquilibriumEquilibrium• trapped molecules reach a balance
between evaporation & condensation
![Page 24: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/24.jpg)
A. Phase ChangesA. Phase Changes
Vapor PressureVapor Pressure• pressure of vapor above
a liquid at equilibrium
IMF v.p.temp v.p.
• depends on temp & IMF• directly related to volatility
temp
v.p
.
![Page 25: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/25.jpg)
A. Phase ChangesA. Phase Changes
Boiling Point• temp at which v.p. of liquid
equals external pressure
IMF b.p.Patm b.p.
• depends on Patm & IMF
• Normal B.P. - b.p. at 1 atm
![Page 26: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/26.jpg)
Which has a higher m.p.?• polar or nonpolar?• covalent or ionic?
A. Phase ChangesA. Phase Changes
Melting Point• equal to freezing point
polar
ionic
IMF m.p.
![Page 27: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/27.jpg)
A. Phase ChangesA. Phase Changes
Sublimation
• solid gas
• v.p. of solid equals external pressure
EX: dry ice, mothballs, solid air fresheners
![Page 28: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/28.jpg)
B. Heating CurvesB. Heating Curves
Melting - PE
Solid - KE
Liquid - KE
Boiling - PE
Gas - KE
![Page 29: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/29.jpg)
B. Heating CurvesB. Heating Curves
Temperature Change• change in KE (molecular motion) • depends on heat capacity
Heat Capacity• energy required to raise the temp of 1
gram of a substance by 1°C
![Page 30: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/30.jpg)
B. Heating CurvesB. Heating Curves
Phase Change• change in PE (molecular arrangement)• temp remains constant
Heat of Fusion (Hfus)
• energy required to melt 1 gram of a substance at its m.p.
![Page 31: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/31.jpg)
B. Heating CurvesB. Heating Curves
Heat of Vaporization (Hvap)
• energy required to boil 1 gram of a substance at its b.p.
EX: sweating, steam burns, the drinking bird
![Page 32: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/32.jpg)
C. Phase DiagramsC. Phase Diagrams
Show the phases of a substance at different temps and pressures.
![Page 33: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/33.jpg)
The following slides… same information, different explanation and examples
![Page 34: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/34.jpg)
Phase Changes
![Page 35: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/35.jpg)
Why do liquids and solids form at all?
• KMT postulates– A gas is a collection of small particles traveling in
straight-line motion and obeying Newton's Laws. – The molecules in a gas occupy no volume. – Collisions between molecules are perfectly elastic
• no energy is gained or lost during the collision
– There are no attractive or repulsive forces between the molecules.
– Kinetic energy is proportional to temperatureX
![Page 36: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/36.jpg)
What is a phase?• Region of matter that is:
– chemically uniform– physically distinct– mechanically separable.
• Often synonymous with (same meaning as) “state of matter”
![Page 37: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/37.jpg)
Changing phases
Distinguish liquid vs. solid?
![Page 38: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/38.jpg)
Properties of …• Gas phase
– Like/unlike soccer players on field
• Liquid phase– Like/unlike crowd at a rally– Like/unlike gases
• Solid phase– Like/unlike movie theatre
• Compare intermolecular interactions – gases vs. liquids vs. solids
![Page 39: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/39.jpg)
Phases of matter
Add
mor
e en
ergy
![Page 40: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/40.jpg)
Phase change vocabulary
![Page 41: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/41.jpg)
Phase changes and IMF’s• As InterMolecular Forces increase, melting
and boiling temperatures _________? (increase or decrease)?
Metallic bonding
Network covalent bonding
Larger sphere, higher
melting point
![Page 42: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/42.jpg)
Strength of interactions
• Which simulation has stronger intermolecular interactions? A or B– How do you know?
A BSame temperature
![Page 43: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/43.jpg)
Ranking of intermolecular interactions • Water• Wood• Iron• Air• Gold• Mercury• Carbon dioxide• Oxygen• Gasoline• Lead
vs.
Why?
![Page 44: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/44.jpg)
Why is water special?
• Periodic trends– Boiling and melting points of hydrides
![Page 45: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/45.jpg)
KMT, energy and phase
changes
![Page 46: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/46.jpg)
Total energy
![Page 47: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/47.jpg)
Water phases present?
![Page 48: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/48.jpg)
Heating curves
Why are b and d flat?
![Page 49: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/49.jpg)
Boiling vs. melting
Which takes more energy?(same mass)
![Page 50: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/50.jpg)
Consider liquid gasEvaporation removes energy
![Page 51: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/51.jpg)
Evaporative Cooling
![Page 52: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/52.jpg)
Evaporation and volatility
• Evaporation– molecules at the surface gain enough energy
to overcome attractive intermolecular forces (IMF)
• Volatility– measure of evaporation rate– depends on temperature and IMF
![Page 53: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/53.jpg)
Volatility
Kinetic Energy
# o
f P
art
icle
s
Boltzmann Distribution
temp
volatility
IMF
volatility
![Page 54: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/54.jpg)
Boiling – Fixed temperature
![Page 55: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/55.jpg)
Why do liquids boil?• Boiling Point
–T at which liquid vapor pressure = atmospheric pressure• depends on Patm & IMF
–Normal boiling point - b.p. at 1 atm
IMF b.p.Patm b.p.
![Page 56: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/56.jpg)
Temperature/pressure phase diagram for water
![Page 57: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/57.jpg)
Transition to Supercritical CO2
![Page 58: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/58.jpg)
Interpret phase diagram for water
![Page 59: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/59.jpg)
Draw a phase diagram for NH3
(used as a refrigerant in RV’s and solar cooling systems)
![Page 60: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/60.jpg)
Ammonia phase diagram
![Page 61: I. Intermolecular Forces](https://reader036.vdocuments.mx/reader036/viewer/2022062720/56813584550346895d9ce3f5/html5/thumbnails/61.jpg)
Phase Changes Need to know…
• Know why liquids and solids exist at all– Failure of KMT postulate
• Know phase names and changes – molecular views of phases and changes– distinguish S vs. L on molecular level
• Explain heating curve origins and parts– Why no change in T during phase change?
• Explain differences and similarities between evaporation, volatility and boiling
• Explain evaporative cooling on a molecular level
• Interpret temperature-pressure phase diagrams