Solids Liquids Gases. BURN SUGAR (ring-stand) OR MELT CHOCOLATE Ask students why they smell what they do?

Solids Liquids Gases

BURN SUGAR (ring-stand) OR MELT CHOCOLATE

Ask students why they smell what they do?

3

Kinetic Theory of Matter

• All matter is made up of atoms and molecules that act like tiny particles. These tiny particles are always in motion.

Gas Law Assumptions

1. The particles in a gas are considered to be small hard spheres with an insignificant volume. (lots of empty space and electrical attraction is nil).

2. The motion of the particles in a gas is rapid, constant and random

3. The collisions between gas particles is elastic.

Newton’s Cradle

• Elastic vs Inelastic Collisions

• Elastic: kinetic energy is transferred without loss from one object to another in a collision.

• Is the collision elastic or inelastic?

• Measurements indicate that the average speed of oxygen molecules in 20°C air is an amazing 1700km/h. At this speed, the odor from a hot cheese pizza in Washington, D.C., should reach Mexico city in about 115 minutes.

• Why don’t we smell food from Mexico?

7

Bulb Thermometer Temperature

• How hot or cold something is (Colloquial definition)

• The average speed (kinetic energy) of the particles in a substance. (Scientific)

• ↑ Speed = ↑ Temperature

• ↓ Speed = ↓ Temperature

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What Happens if I add a drop of food coloring to a glass of hot and cold water?

Hot Water Cold Water

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White Board Brainstorm

• What are the three states of matter?

• Tell me something about each state of matter?

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SOLID LIQUID GAS

Shape

Volume

Particle Motion

Arrangement

Picture

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SOLID LIQUID GAS

Shape Rigid with a definite or Fixed Shape.

Volume

Particle Motion

Arrangement

Picture

12

SOLID LIQUID GAS


Volume Definite Volume. Not compressible.

Particle Motion

Arrangement

Picture

13

SOLID LIQUID GAS



Particle MotionParticles Vibrate but are generally locked

into place.

Arrangement

Picture

14

SOLID LIQUID GAS




into place.

ArrangementVery close together

in an orderly arrangement

Picture

15

SOLID LIQUID GAS




into place.



Picture

16

SOLID LIQUID GAS


Takes the shape of its container



into place.



Picture

17

SOLID LIQUID GAS




Definite volume. Not compressible.


into place.



Picture

18

SOLID LIQUID GAS






into place.

Particles slide past one another (liquids

can flow)



Picture

19

SOLID LIQUID GAS






into place.


can flow)



Close together but not locked into an

orderly arrangement.

Picture

20

SOLID LIQUID GAS






into place.


can flow)





Picture

21

SOLID LIQUID GAS


Takes the shape of its container Fills a container




into place.


can flow)





Picture

22

SOLID LIQUID GAS





Indefinite volume. Easily compressible

(e.g. a balloon)


into place.


can flow)





Picture

23

SOLID LIQUID GAS






(e.g. a balloon)


into place.


can flow)Move rapidly with very high energy.





Picture

24

SOLID LIQUID GAS






(e.g. a balloon)


into place.







Particles are very far apart.

Picture

25

SOLID LIQUID GAS






(e.g. a balloon)


into place.







Particles are very far apart.

Picture

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Student Demonstration

• Pretend you are a tiny particle and demonstrate the motion of atoms and molecules in a solid liquid and gas.

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Hamper with Wet Clothes

• What Happens if you try to stuff wet clothes inside to make more room.

• Use this analogy to explain the volume of solids, liquids and gases.

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PHET Physics S-L-G

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Liquid Party!

• As a Liquid, water molecules slide around one another and move freely. They dance and are very happy, maybe a bit terrified at times but who really knows for sure.

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Gas can really clear a room!

• As a gas H20 is very sad. All of its friends are very far away and it is very lonely.

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As Ice H20 is also Sad: the molecules lock into place and are unable to move about freely!

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Changes of State

• Freezing Point: temperature at which liquid becomes a solid (Water = 0°C)

• Boiling Point: temperature at which liquid becomes a gas (Water = 100°C)

• Melting Point: temperature at which a solid becomes a liquid (Ice = 0°C)

• Are changes of state chemical or physical changes?

34

Evaporation: When a liquid turns into a gas

Steam is High energy H20 gas Sweating is a cooling process

35

Condensation: when gas turns into a liquid

Water forms outside a glass filled with ice and water.

Bathroom mirror after showering or a car windshield.

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Sublimation: when a solid turns directly into a gas

Dry Ice or Carbon Dioxide (CO2) turns directly into gas.

Deposition is the opposite of sublimation. Gas solid. This is how precipitation (snowflakes) forms in clouds.

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Phase Change of Water

39

What Happens if I put a balloon over an Erlenmeyer Flask and put it on a hot plate/burner? Why?

Erlenmeyer Flask Balloon

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What Happens if I put a balloon over an Erlenmeyer Flask with already boiling water? Why?

Erlenmeyer Flask Balloon

41

Volume and Temperature

• When you heat a substance the particles move faster and the amount of space they take up increases.

• We saw this with the balloon and Erlenmeyer flask on a hot plate.

What is another word for the amount of space and object takes up?

42

Volume and Temperature

• When a substance cools the particles move slower and the amount of space they take up decreases.

• When cooled an inflated balloon returns to where it originally started as the particles slow down.

43

What happens to basketball when it gets cold?

• The air molecules inside the ball move slower and this lowers the outward pressure and the ball deflates and loses its bounce.

44

Balloons and Expansion

45

Solid Block

Heat

The Solid Expands

The mass stays the same but its volume increases.What happens to the density of the object?

46

D = M/V

• If a solid object has a mass of 24g and a volume of 12cm3, what is its density and what will happen if it is heated?

• If the object expands to a volume of 16cm3 while being heated, what is its mass and what is its new density?

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Solids do Expand

Ball and Ring Apparatus

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Why do Bridges have expansion joints?

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Summary

• Density Decreases as Temperature Increases

• Density Increases as Temperature Decreases

• Substances Expand when Heated

• Substances Contract when Cooled

T↑ V↑ D↓ T↓ V↑ D↑

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Violating Kinetic Theory

• What happens if you put a can of soda in the freezer and leave it there?

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• Shouldn’t it contract (get smaller) as it cools?

• Why does it expand and explode?

52


• Ice is colder than liquid water so shouldn’t it be more dense and sink?

• Does Ice Sink in water?

53

Just the Tip of the Iceberg!!!

54

Density Ice = 0.9g/cm3

55

Water is an Exception!!!!

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Water is an Exception!!!!

• Water is one of the few known substances that doesn’t always contract as it gets colder.

• Water behaves normally most of the time but between 0°C and 4°C it behaves oddly.

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Peculiar H20

• Water at 4°C will EXPAND when cooled until 0°C at which point it becomes ice.

• Likewise, as Ice at 0°C melts it CONTRACTS as it turns into a liquid.

• Outside of this narrow range, water behaves normally but this is why soda left in the fridge explodes!

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(-20°C)---------(0°C)---(4°C)---------------------------------(100°C)

Water behaves oddly between 0

and 4C

Water behaves normally and contracts when cooled and expands when heated.

THIS IS VERY IMPORTANT FOR LIFE AS WE KNOW IT!!!!

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O

H H+

-

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O

H H+

-Opposite Charges Attract ( + and - )

Like Charges Repel( + and + or - and - )

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Water as a Polar Molecule

Balloon/Comb Demo Perform Polarity mini-Lab

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Penny Drop DataStudent # Drops Student # Drops Student # Drops Student # Drops

Documents

Solids Liquids Gases. BURN SUGAR (ring-stand) OR MELT CHOCOLATE Ask students why they smell what they do?