THE 3 KINETIC THEORY

ASSUMPTIONS

WHAT – HOW – WHY? What: Explain assumptions of the

Kin. Theory of gases and gas pressure. 1.2d RWC -3.2f/g, 4d

How: Explain the three assumptions of Kin. Theory and how it relates to gas pressure. Give 3 everyday examples to defend your answer.

Why?Why do new cars get Nitrogen in their tires instead of regular air?

KINETIC THEORY

The study of molecules and their behavior in all states of matter (solid, liquid and gas)We will be focusing on GAS BEHAVIOR

Kinetic = MOTION!!

BASIC 3 ASSUMPTIONS 1. All matter is composed of

small particles.

2. Small particles are CONSTANTLY in motion.

3. All collisions between particles are PERFECTLY ELASTIC (which means

there is NO loss of energy when they hit)

IN A GROUP OF THREE!! Person 1: Describe an everyday

example to support assumption #1.

Person 2: Describe an everyday example to support assumption #2.

Person 3: Describe an everyday example to support assumption #3.

Share out!!

PRESSURE Caused by the force of collision and the #

of collisions with the walls of a container.

Standard Pressure (air pressure at sea level) is 101.4 kPa. (kilopascals) = 1atm

The pressure in Colorado Springs, CO is 1. >101.4 kPa 2. <101.4 kPa

Pair share what this means as far as the force and number of collisions with the “walls” of the atmosphere here.

MAKE SOME PREDICTIONS ON WHITEBOARDS!!

How is pressure related to temperature? 1. As temperature increases, pressure increases. 2. As temperature increases, pressure

decreases.

On a whiteboard, draw the graph PvT.

How is pressure related to volume? 1. As volume increases, pressure increases. 2. As volume increases, pressure decreases.

On a whiteboard, draw the graph PvV.

SOME EVERYDAY EXAMPLES TO ILLUSTRATE THESE RELATIONSHIPS This is an example of the

1. Pressure vs Volume relationship 2. Pressure vs Temperature relationship

In the winter, my tires are flatter than in the summer.

When I expand my chest (make my lungs bigger) air rushes in, making me breath.

When I heat water in a pot, eventually it will boil and turn into a gas.

GENERATE 2 EVERYDAY EXAMPLES TO ILLUSTRATE THESE RELATIONSHIPS

In your notebook, describe an everyday example of EACH of the relationships (2 sentences)

Now quiz your partner, and have them guess which one matches which relationship.

Share out 1 from each group.

This is an example of the 1. Pressure vs Volume relationship 2. Pressure vs Temperature relationship

STANDARD UNIT OF TEMPERATURE IN SCIENCE The Kelvin (K)

Absolute Zero – what happens here?The temperature at which ALL molecular

motion ceases (theoretical!!)

Conversions between K and Celsius are EASY!!

K = *C + 273

PROPERTIES OF THE 3 STATES OF MATTER

Solid Matter

HIGHLY restricted motion of the molecules (BUT THEY ARE STILL MOVING!!)

Particles “vibrate” around a fixed point.

Shape?1. FIXED 2. TAKES SHAPE OF

CONTAINER Volume?

1. FIXED 2. FILLS CONTAINER

PROPERTIES OF THE 3 STATES OF MATTER

Liquid

Restricted particle motion, but more free than solids.

Particles “vibrate” but slip past one another so they can “flow”

Shape? 1. FIXED 2. TAKES SHAPE OF

CONTAINER Volume?

1. FIXED 2. FILLS CONTAINER

PROPERTIES OF THE 3 STATES OF MATTER

Gases Independent, STRAIGHT-LINE motion. Collisions only will change particle

direction. Travel in a RANDOM manner, depending on

collisions.

Shape? 1. FIXED 2. TAKES SHAPE OF

CONTAINER Volume?

1. FIXED 2. FILLS CONTAINER

YOU’VE HAD A FEW EXAMPLES

In your notebooks, describe an everyday example to show the following:1. That solids have fixed shape and

volume.

2. That liquids have fixed volume but variable shape.

3. That gases have variable volume and shape.

Pair Share and whip around!!

WHAT – HOW – WHY? What: Explain assumptions of the

Kin. Theory of gases and gas pressure. 1.2d RWC -3.2f/g, 4d

How: Explain the three assumptions of Kin. Theory and how it relates to gas pressure. Give 3 everyday examples to defend your answer.

Why?Why do new cars get Nitrogen in their tires instead of regular air?

DOL GOAL 3 REAL WORLD EXAMPLES!! 1. List the three basic assumptions of

the Kinetic Theory and relate them to the behavior of gases. (6pts)

2. Give an everyday example for each of the 3 assumptions. Be specific as you detailing the behavior of the gas in the example. (3pts)

DOL EXEMPLAR!! 1. All matter is composed of small particles. (2pts)

Gases are composed of small particles/molecules. 2. Small particles are CONSTANTLY in motion. (2pts)

Gas particles are ALWAYS in motion (the freest of the three states of matter)

3. All collisions between particles are PERFECTLY ELASTIC. (2pts) When gas particles hit each other, they bounce back with

a combined EQUAL energy as what was put into the collision.

4.-6. Everyday example of EACH of the above three. MUST BE SPECIFIC in their description (3pts)