Gases Day 2
Standard 4:The kinetic molecular
theory describes the motion of atoms
and molecules and explains the
properties of gases.
Objective
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I can explain gas
properties using the
kinetic molecular
theory of gases.
Agenda
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Catalyst
Balloon in a bottle
KMT! Notes & Videos
KMT practice
Exit Slip
Catalyst
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Turn in your reading questions
from last class.
Convert the temperatures into
Kelvin: (write on a whiteboard)
 Warmest November day in
LA: 37.7° C (100° F) on
November 1, 1966.
 Coldest November day in
LA: 1.1 ° C (34° F) on
November 19, 1886.
Bad Guys Like Gas, Why?
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Write on a whiteboard: Video Focus Question:
How does the gas move in the video? Thinking
about how gases move, what are some benefits
and disadvantages of using gas as a weapon?
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http://www.youtube.com/watch?v=iOkPaSwXC6s
Balloon in a Bottle Activity
Mini Vocabulary Review
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Volume
a measure of the size of an object in three dimensional space.
kinetic energy
the energy of an object that is due to the object’s motion.
Pressure
the amount of force exerted per unit area on a surface.
temperature
a measure of the average kinetic energy of the particles in an
object.
The Kinetic Molecular Theory
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The Kinetic Molecular Theory
is a way to explain the
properties of gases by
examining the movement of
gas particles at the
microscopic level.
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Gases that obey the Kinetic
Molecular Theory are called
Ideal Gases
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Just like there are no “ideal”
people, there are actually no
ideal gases. But gases do
approach ideal behavior.
The KINETIC MOLECULAR
THEORY!
1. Gases consist of tiny particles
(molecules or atoms).
2. The particles are TINY compared to the
space between them. So, we do not
count the volume of the particles.
Itty-bitty
Space between = BIG
Itty-bity
KMT continued
3. The particles are in constant RANDOM
motion. The particles collide with the
walls of the container. These collisions
result in pressure.
Exerts
pressure
More KMT!
4. The gas particles do not attract or repel
each other. They move randomly.
5. The average kinetic energy of the gas is
proportional to the Kelvin temperature.
Kinetic
Energy
Temperature
Let’s use the KMT to explain some
gas properties.
Diffusion
Pressure &
Temperature
Pressure &
Volume
Pressure & #
of molecules
We are about to do a demonstration and watch some videos. Take
notes and draw pictures in the boxes on your worksheet.
Think about how to explain what you see using the KMT (think
about the constant and random motion of particles).
Diffusion
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Diffusion is the
movement of
particles from
regions of high
concentration to
low
concentration.
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The random movement of gas particles
causes diffusion.
Pressure and Temperature
When temperature increases, pressure
________.
 When temperature decreases, pressure
_______.
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http://www.youtube.com/watch?v=HiLeji8bLOk
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Think, Pair, Share: What happened in the
video and why?
Pressure and Volume
As volume increases, pressure ________.
 As volume decreases, pressure _______.
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http://www.grc.nasa.gov/WWW/k-12/airplane/aboyle.html
http://www.youtube.com/watch?feature=endscreen&v=ULdmv-iPQvA&NR=1
Think, Pair, Share: What happened in the
video and why?
Pressure and Number of Moles
As the number of molecules increases,
pressure __________.
 As the number of molecules decreases,
pressure __________.
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http://www.youtube.com/watch?v=t-Iz414g-ro
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Think, Pair, Share: What happened in the
video and why?
KMT Practice: Example
1.
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Richard bought a new soccer ball and it came deflated.
As he pumps air molecules into the soccer ball, the
pressure inside the soccer ball _________. Why?
With more molecules moving randomly and rapidly
in the ball, they will hit the sides more, increasing
pressure.
Practice
Work independently or with a partner.
 Complete the practice problems and
activity.
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Challenge: Use a word processing or drawing
application on your iPad to make your poster.
Turn it in through the class edmodo page.
Homework
Complete any unfinished practice
problems and your poster (paper or digital)
 Read pp. 416-422 Do problems pp. 422
#1-7. (Additional resources on the class
website)
 Optional: Flashcards: diffusion, kinetic
molecular theory, directly proportional,
inversely proportional, density, compress
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Exit Slip Answers 4a & 4b
4a: (1) Aerosol cans have a warning not to dispose of them in
fires. Why? (use KMT)
They are pressurized. The gas will explode when exposed to
heat because the kinetic energy of molecules will increase
until the pressure inside is too much for the can.
(2) As the kinetic energy of molecules increases, the
temperature _increases_. Why?
Temperature is a measure of the kinetic energy of molecules.
4b: (3) Why does gas diffuse through air?
The molecules move randomly, causing diffusion.
(4) How are molecules of different chemicals arranged when
diffusion is complete?
They are all spread out and mixed together as much as
possible. They form a homogenous mixture or solution.