CH. 13.1 NOTES
States of Matter

Types of Kinetic Energy
• Kinetic = motion
• Kinetic Energy: energy an object has
– Translation: forward motion
– Rotational: spinning motion
– Vibrational: vibrating motion

Kinetic Theory
• All matter consists of tiny particles that are in constant motion.
• As a basis for this theory, there are 3 fundamental assumptions. They are:

Kinetic Theory:
1. Particles in a gas are small, hard spheres (no volume)

Kinetic Theory
2. Gas particles are in rapid, constant, random motion.

Kinetic Theory
3. Collisions are perfectly elastic (travel in straight lines)

Kinetic Energy
•
Kinetic Energy is directly proportional to
Kelvin temperature.

Kinetic energy vs. Temperature
• Average temperature doesn’t mean every molecule has the same kinetic energy.
•
-Absolute zero=all motion of particles ceases and has no kinetic energy . K = o C + 273

Kinetic Theory
•
This explains diffusion: tendency of molecules to move to areas of lower concentration until concentration is uniform throughout.

Properties of Gases
• Expansion: gases don’t have a definite shape so they completely fill any container they are in
• Fluidity: because there are no forces between the particles in a gas, they slide right by each other (fluid) What is another fluid?

Properties of Gases
• Low Density: gases are not dense because their particles are so far away from eachother
• Compressibility: The volume of a gas can be decreased significantly because particles are far away from each other. (think of air pressure in tires)

Properties of Gases
• Diffusion and Effusion:
– Gases spread out and mix with one another without being stirred.
– Diffusion: spontaneous mixing of two gases caused by random motion
– Effusion: when gas particles pass through a tiny opening

Gas Pressure
• -Gas pressure is caused by collisions of molecules
• -Empty space with no particles is a vacuum.

PRESSURE
• Is defined as: Force/unit area of a surface
• Has the equation: P=F/A
• Uses the following units:

Unit Symbol
Millimeters of mercury
Mm Hg
Atmosphere Atm
Pascal
Torr
Pa
Torr
Conversion
Factor
Pressure that supports 1 mm of Hg in a barometer
760 mm Hg
1.01 x 10 5 Pa
1N/m 2
1 mm Hg

Pressure
• -Barometer measures atmospheric pressure.
• 1atm = 760 mmHg = 760 torr = 101.3kPa
– (Atm =atmospheres kPa = kilopascal)

Converting pressure
• 1. Convert 450 kPa to:
• a. mm Hg
• 2. Convert 2.5 atm to: b. atm
• a. kPa b. mm Hg
• 1atm = 760 mmHg = 760 torr = 101.3kPa

Answers
•
•
1a. 450 kPa | 760 mmHg = 3376 mmHg
| 101.3 kPa
•
•
•
1b 450 kPa | 1 atm = 4.44 atm
| 101.3 kPa
• 2a. 253kPa 2b. 1900mmHg

Ch. 13.2
The Nature of Liquids

Gases and Liquids are Fluid

Gases and Liquids are Fluid
• Atoms and Mc’s in a liquid move in a random pattern relative to one another bc the intermolecular forces are too weak to hold the atom and mc’s in a solid form.

• Vapor Pressure: pressure exerted by mc’s that have evaporated from liquid.
– Increase temperature=increase kinetic energy=increase vapor pressure

Dynamic equilibrium: occurs when vapor pressure no longer fluctuates
(changes).
• Rate of evaporation = rate of condensation

Boiling Point: When Vapor Pressure =
Atmospheric Pressure
• Make things boil by:
– Increase temperature
– Lower atmospheric pressure

Boiling point is lower in the mountains
• Normal Boiling Point: temperature substance boils at

Vapor Pressure and Boiling Point
• Which compound is:
1. Most volatile?
2. Strongest IMF (intermolecular forces)
3. Highest b.p.?

13.4
Phase Changes

Phase diagram

Phase Diagram

Phase Diagram

Phase Change Diagram