Embed Size (px)
Citation preview
Liquids & SolidsLiquids & SolidsLiquids & SolidsLiquids & Solids
I. Intermolecular Forces
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
B. Types of IMFB. Types of IMF
B. Types of IMFB. Types of IMF
London Dispersion Forces
View animation online.
B. Types of IMFB. Types of IMF
Dipole-Dipole Forces
+ -
View animation online.
B. Types of IMFB. Types of IMF
Hydrogen Bonding
C. Determining IMFC. Determining IMF
NCl3• polar = dispersion, dipole-dipole
CH4
• nonpolar = dispersionHF
• H-F bond = dispersion, dipole-dipole, hydrogen bonding
II. Physical Properties
Liquids & SolidsLiquids & SolidsLiquids & SolidsLiquids & Solids
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
B. Liquid PropertiesB. Liquid Properties
Surface Tension• attractive force between particles in a
liquid that minimizes surface area
B. Liquid PropertiesB. Liquid Properties
Capillary Action• attractive force between the surface of
a liquid and the surface of a solid
water mercury
C. Types of SolidsC. Types of Solids
Crystalline - repeating geometric pattern• covalent network• metallic• ionic• covalent molecular
Amorphous - no geometric pattern
decreasingm.p.
C. Types of SolidsC. Types of Solids
Ionic(NaCl)
Metallic
C. Types of SolidsC. Types of Solids
CovalentMolecular
(H2O)
CovalentNetwork
(SiO2 - quartz)
Amorphous(SiO2 - glass)
Ch. 12 - Liquids & SolidsCh. 12 - Liquids & SolidsCh. 12 - Liquids & SolidsCh. 12 - Liquids & Solids
III. Changes of State
A. Phase ChangesA. Phase Changes
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
A. Phase ChangesA. Phase Changes
Kinetic Energy
# o
f P
art
icle
s
p. 477
Boltzmann Distribution
temp
volatility
IMF
volatility
A. Phase ChangesA. Phase Changes
EquilibriumEquilibrium• trapped molecules reach a balance
between evaporation & condensation
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
p.478
temp
v.p
.
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
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.
A. Phase ChangesA. Phase Changes
Sublimation
• solid gas
• v.p. of solid equals external pressure
EX: dry ice, mothballs, solid air fresheners
Heating Curves
A. Heating CurvesA. Heating Curves
Melting - PE
Solid - KE
Liquid - KE
Boiling - PE
Gas - KE
A. Heating CurvesA. 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• “Volcano” clip -water has a very high heat capacity
A. Heating CurvesA. 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.
A. Heating CurvesA. Heating Curves
Heat of Vaporization (Hvap)
• energy required to boil 1 gram of a substance at its b.p.
• usually larger than Hfus…why?
EX: sweating, steam burns, the drinking bird
B. Phase DiagramsB. Phase Diagrams
Show the phases of a substance at different temps and pressures.
