Transcript Chapter 16 section 1a

Chapter 16 Section 1 Part A
KINETIC THEORY OF MATTER
Kinetic Theory
 Explains how particles behave
 Three basic ideas:
 All matter made of small particles
 All particles are in constant motion
 Particles collide
 Collisions transfer energy
Kinetic Energy
 Remember, kinetic energy is the energy of
motion
 KE = ½ m v2
 Since all particles are moving, all particles
have kinetic energy
 Temperature is the measure of the AVERAGE
kinetic energy of particles in matter
Potential Energy
 Particles also have potential energy
 Potential energy is stored energy
 May be due to gravity, chemical nature
Thermal energy
 Thermal energy is the total energy in matter
 Thermal energy is the sum of kinetic and
potential energy of the particles
 Thermal energy determines the state of
matter
States of Matter
 Five recognized states of matter
 The state depends on the balance between
kinetic and potential energy of the particles
 The states:
 Solid
 Liquid
 Gas
 Plasma
 Bose-Einstein Condensate
Solid
 Particles close together
 Usually packed in a particular pattern (crystal)
 Particles vibrate in place, do not move apart
 As a result:
 Definite volume
 Definite shape
Liquid
 Particles not as close as solid
 Do not have regular pattern
 Particles move and slide past each other
 As a result:
 No definite shape
 Definite volume
Gas
 Particles free to move away from each other
 Particles constantly collide and bounce away
 As a result:
 No definite shape
 No definite volume
Plasma
 Extremely high energy rips electrons away
from atoms
 Interaction of ionic particles
 Example: any star, lightning
Bose-Einstein Condensate
 Proposed by Satyendra Nath Bose and
Albert Einstein in the 1920s
 First created and observed in 1995
 First accomplished by Eric Cornell and Carl
Wieman in Boulder, Colorado
 BEC Homepage
 Gaseous superfluid cooled to near absolute
zero
 All atoms can flow past one another
behaving almost like a synchronized wave
Phase Transitions
 Changing kinetic energy causes a change in
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the state of matter
Change from liquid  gas: vaporization
Change from gas  liquid: condensation
Change from liquid  solid: freezing
(crystallization)
Change from solid  liquid: melting
Each of these changes requires a specific
amount of kinetic energy change
Phase Transitions
 Change from gas  liquid (or vice versa)
requires change in energy
 Heat of vaporization: specific amount of energy
required to change the particle distance and
motion from gas to liquid
 Change from solid  liquid (or vice versa)
requires change in energy
 Heat of fusion: specific amount of energy
required to change the particle distance and
motion from solid to liquid
Phase Transitions
 Melting point (freezing point):
 Temperature at which the substance changes
from liquid to solid (or vice versa)
 Boiling point:
 Temperature at which the substance changes
from liquid to gas (or vice versa)
Phase Transitions
 Not all substances change state in an orderly
way
 Amorphous solids: solids with no orderly
particle structure
 Liquid crystals: keep orderly particle structure
even as a liquid