Transcript Lesson 12.2 and 12.4 Laws of Attraction Phase Change

Lesson 12.2 and 12.4
Laws of Attraction
Phase Change
Intramolecular Forces
Force
Model
Basis
Example
Ionic
Cations and
anions
NaCl
Covalent
Shared electrons H2
Metallic
Metal cations
and mobile
electrons
Fe
Dispersion Forces
Weak Force
Temporary shift in
electron density
clouds
Explains State of Matter
of Halogens
Small to Large
F2 (g)
Cl2 (g)
Br2 (l)
I2 (s)
Dipole-dipole Forces
Permanent forces
Positive – Negative Poles
Hydrogen Bonds
Dipole-dipole attraction
some examples
large electronegative
H-F
H-N
H-O
H-S
Room Temperature
H2O is liquid
NH3 is gas
Questions
Explain what determines a substance’s state
at a given temperature.
Compare intermolecular and intramolecular
forces.
Which molecules can form hydrogen bonds?
a. H2 b. H2S c. HCl
d. HF
Questions
Explain what determines a substance’s state at a
given temperature.
Intermolecular forces – solid very strong, liquid
weaker, gas has none
Compare intermolecular and intramolecular forces.
Intramolecular hold particles together,
intermolecular between particles
Which molecules can form hydrogen bonds?
a. H2 b. H2S c. HCl
d. HF
Phase Change
Phase Changes that Require
Energy
Melting – liquid is warmer than ice, heat is
transferred
Vaporization – liquid to vapor or gas
gradually
Sublimation – direct from solid to gas
Phase Change Release Energy
Freezing – heat is removed
Condensation – what happens to the glass
of ice cold lemonade on a hot day?
Phase Diagram
Triple
Point
Phase Diagram Questions
Explain what the triple point and the critical
point on a phase diagram supplies
Determine the phase of water at 75.00 C
and 3.00 atm.
Explain what the triple point and the critical
point on a phase diagram supplies
Triple point is where all 3 phases can
coexist.
Critical point is temp and pressure above
which a substance is not a liquid
Determine the phase of water at 75.00 C
and 3.00 atm. liquid
Questions
Explain how the addition or removal of
energy can cause a phase change.
Explain the difference between the
processes of melting and freezing.
Compare disposition and sublimation.
Questions
Explain how the addition or removal of
energy can cause a phase change.
Add Energy, increase Kinetic Energy, less
intermolecular forces
Remove Energy, decrease Kinetic Energy,
increase intermolecular forces
Explain the difference between the
processes of melting and freezing.
Freezing: Liquid to solid, release Energy
Melting: Solid to liquid, need to input Energy
Compare disposition and sublimation.
Sublimation: solid to vapor directly, skips
liquid phase
Disposition: Vapor to solid, without liquid
phase