topic: kinetic-molecular theory (kmt)

13
TOPIC: Kinetic- TOPIC: Kinetic- Molecular Theory Molecular Theory (KMT) (KMT) Do Now: packet page __ Do Now: packet page __ Relationship between Relationship between Temp and Average Kinetic Temp and Average Kinetic Energy Energy

Upload: sutton

Post on 28-Jan-2016

51 views

Category:

Documents


0 download

DESCRIPTION

Do Now: packet page __ Relationship between Temp and Average Kinetic Energy. TOPIC: Kinetic-Molecular Theory (KMT). Models. Scientists use models because simpler than real life Kinetic-molecular theory can be extended to all phases of matter. - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: TOPIC: Kinetic-Molecular Theory (KMT)

TOPIC: Kinetic-Molecular TOPIC: Kinetic-Molecular Theory (KMT)Theory (KMT)

Do Now: packet page __Do Now: packet page __

Relationship between Temp Relationship between Temp and Average Kinetic Energyand Average Kinetic Energy

Page 2: TOPIC: Kinetic-Molecular Theory (KMT)

ModelsModels

•Scientists use models Scientists use models because simpler than real lifebecause simpler than real life

•Kinetic-molecular theory can Kinetic-molecular theory can be extended to all phases of be extended to all phases of mattermatter

Page 3: TOPIC: Kinetic-Molecular Theory (KMT)

Kinetic-Molecular Theory Kinetic-Molecular Theory (KMT) as it pertains to (KMT) as it pertains to

ideal gasesideal gasesThere are 4 assumptions to the KMT

Page 4: TOPIC: Kinetic-Molecular Theory (KMT)

Real vs. ideal gasReal vs. ideal gas

• Ideal gasIdeal gas obeys assumptions of KMT obeys assumptions of KMT all the time all the time • ItIt’’s s a modela model

• It It doesndoesn’’t existt exist

• Real gasesReal gases follow KMT most of time, follow KMT most of time, but but notnot at at high pressure & low high pressure & low temperaturetemperature• KMT breaks down when molecules are KMT breaks down when molecules are

close togetherclose together

Page 5: TOPIC: Kinetic-Molecular Theory (KMT)

1) Gases consist of spherical 1) Gases consist of spherical molecules moving in constant, molecules moving in constant, random, straight-line motionrandom, straight-line motion

Random, straight-line?Random, straight-line?

- move in straight- move in straight

lines until hit lines until hit

something, then can something, then can

bounce bounce

off at any angleoff at any angle

Page 6: TOPIC: Kinetic-Molecular Theory (KMT)

2) Gas particles undergo 2) Gas particles undergo ““elasticelastic”” collisions with each other and collisions with each other and with walls of containerwith walls of container

““ElasticElastic”” means total KE is means total KE is conservedconserved

• KE does KE does notnot get converted to heat get converted to heat or sound or any other kind of or sound or any other kind of energyenergy

• KE KE cancan be transferred between be transferred between particlesparticles

Page 7: TOPIC: Kinetic-Molecular Theory (KMT)

3) Gas molecules separated by such 3) Gas molecules separated by such great distances that the volume of great distances that the volume of molecule is negligible (not molecule is negligible (not significant)significant)

• Ideal gasses are considered not to have Ideal gasses are considered not to have volume, but they still have a mass, so volume, but they still have a mass, so scientists call this a point massscientists call this a point mass

Page 8: TOPIC: Kinetic-Molecular Theory (KMT)

4)4) Gas molecules do not attract or Gas molecules do not attract or repel each otherrepel each other

Page 9: TOPIC: Kinetic-Molecular Theory (KMT)

4)4) Real gases do interact with one Real gases do interact with one another…that’s why water vapor another…that’s why water vapor condenses…condenses… Intermolecular

forces

Page 10: TOPIC: Kinetic-Molecular Theory (KMT)

Ideal vs RealIdeal vs Real

• IdealIdeal• Particles Particles

themselves themselves take up no take up no spacespace

• Particles have Particles have no no intermolecular intermolecular forcesforces

• Real ( at Real ( at high high pressure & low pressure & low temperature)temperature)• Particles take up Particles take up

space (they have space (they have volume)volume)

• All gas particles All gas particles are subject to are subject to intermolecular intermolecular interactions interactions

Page 11: TOPIC: Kinetic-Molecular Theory (KMT)

Example: N2(g)

At a low temperature, the kinetic energy is…

low, which means their intermolecular forces are strong enough to hold them together

Nitrogen gas become liquid Nitrogen

Page 12: TOPIC: Kinetic-Molecular Theory (KMT)

Propane

If you increase the pressure, the volume…

decreases, which forces particles closer together. They will become a liquid