View
34
Download
0
Category
Preview:
DESCRIPTION
Kinetic Theory of Matter (KTM). AKA: Kinetic Molecular Theory (KMT) Molecular Kinetic Theory (MKT) Not associated with TKM—the international postal code for Turkmenistan. Rule 1. All matter is composed of particles in constant motion. Rule 2. - PowerPoint PPT Presentation
Citation preview
Kinetic Theory of Matter (KTM)
AKA: Kinetic Molecular Theory (KMT) Molecular Kinetic Theory (MKT)
Not associated with TKM—the international postal code for
Turkmenistan
Rule 1
• All matter is composed of particles in constant motion
Rule 2
• Temperature is a measure of the kinetic energy of the particles.
Rule 2 (a and b)
• Temperature is a measure of the kinetic energy of the particles.
a) When you heat a sample, the particles speed up
b) When you cool a sample the particles slow down
After that, things get hazy.
?
Consider the state:
• Solid Liquid Gas
Particles in motion:
• Solid Liquid Gas
Particles in motion:
• Solid Liquid Gas
Vibrating about a fixed
position
Particles in motion:
• Solid Liquid Gas
Moving over and around other particles,
unlikely to escape surface
Particles in motion:
• Solid Liquid Gas
Moving freely, colliding with other particles and the walls of container
Consider state changes:
Liquid
Solid GasSublimation
Boiling
, ev
apor
ation
,
vapo
rizat
ionFreezing
Melting
Conde
nsat
ion
Particles on particles:
• Solid Liquid Gas
Particles not touching
Particles in contact
Particles in contact
This is huge. Really.
Values and preferred units
• P—atmospheres• T—kelvins• V—Liters• n—moles
Conversions
• P: 1 atm =760 mmHg=760torr=101.3 kPa=101,325
Pa
• T: T(k) = T(oC) + 273
• V: 1L=1000 ml=.001 m3
How fast do particles move?
It depends on:
How fast do particles move?
It depends on:
• Temperature:
• Size of the particle:
How fast do particles move?
It depends on:
• Temperature: High T faster motion
• Size of the particle: Smaller faster
Cool, medium, warm
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
What about water?
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
What about water?
Water melts / freezes
Water boils/ condenses
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
What about water?
Water is a solid
Water is a liquid
Water is a gas
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
What about water?
Water is a solid
Water is a liquid Water is
a gas
Increasing pressure will
melt ice
Decreasing pressure will
boil water
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
What about water?
Water is a solid
Water is a liquid Water is
a gas
Sublimation occurs at low T and P
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
What about water?
Water is a solid
Water is a liquid Water is
a gas
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
Describe these processes
A
H
D
B
IG
E
C
F
Water is a solid
Water is a liquid
Water is a gas
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
Describe these processes
Heating curve lab
Vacuum pump demo
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
Water
Normal boiling point
Normal melting point
Triple point
Phase diagrams
T
P
0 k
0 atm
1 atm
273 k 373 k
Water
Critical pressure
Phase diagrams
T
P
0 k
0 atm
Most other substances
Critical pressure
Critical temperature
The phase diagram for water
Phase diagrams
T
P
0 k
0 atm
1 atm
Phase diagrams
T
P
0 k
0 atm
Critical pressure
Critical temperature
1 atm
The phase diagram for CO2
The phase diagram for water
Can you explain why each of these phenomena occurs?
Thermal expansion of a solid—solids expand when heated
Thermal expansion of a liquid –liquids expand when heated
Thermal expansion of a gas –gasses expand when heated
Can you explain why each of these phenomena occurs?
Compressibility of gasses—gasses can be compressed into a smaller volume
Incompressibility of liquids –liquids can’t be compressed into a smaller volume
Incompressibility of solids –solids can’t be compressed into a smaller volume
Can you explain why each of these phenomena occurs?
Conduction of heat between two objects in contact—the cool one warms up.
Heat flow stops when temperatures are equal
Can you explain why each of these phenomena occurs?
Fluidity of gasses—gasses flow, they have no fixed shape
Fluidity of liquids—liquids flow, they have no fixed shape
Rigidity of solids—solids do not flow, they have a fixed shape
Can you explain why each of these phenomena occurs?
Melting point of a solid —at a certain temperature, a solid changes into a liquid
Boiling point of a liquid —at a certain temperature, a liquid changes into a gas
Freezing point of liquids –at a certain temperature, a liquid changes into a solid
Melting is endothermic (requires heat)Boiling is endothermic (requires heat)
Can you explain why each of these phenomena occurs?
Liquification of gasses is accomplished at low temperatures and high pressures
Sublimation of solids (to gas) at low pressures
Sublimation of solids (to gas) at high temperatures
Evaporation cools a liquidYou can see your breath on a cold day
Can you explain why each of these phenomena occurs?
Boyle’s Law —when the volume of a gas is reduced, its pressure increases
Charles’ Law —when gasses are cooled, their volumes act as if they will reach zero volume at a temperature of absolute zero
Avogadro’s Law —identical volumes of gasses contain the same number of particles
Graham’s law —heavier gasses diffuse slowerDalton’s law of partial pressures —the total
pressure of a mixture of gasses is the sum of the pressures of each gas.
Can you explain why each of these phenomena occurs?
Decrease in boiling point of a liquid with lower pressure
Increase in boiling point when solutes are added to a solvent
Decrease in freezing point when solutes are added to a solvent
Metals conduct heat better than other solids
Recommended