Topic: Chemistry

Aim: Explain the different types of phase changes and the energy changes involved.

Do Now: Write the aim on today’s notes sheet. Tape today’s notes sheet on the back of yesterday’s notes.

HW: Properties Reading due Monday!

SOLID LIQUID GAS

Let’s summarize… Identify the phase being described (solid, liquid or gas):

1. No definite shape or volume.

2. Takes the shape of the container it is in and has a definite volume.

3. Made up of high energy atoms.

4. Atoms are tightly packed together.

5. Molecules are cohesive.

6. Has a definite shape and volume.

7. Takes the shape of a closed container.

Gas

LiquidGas

SolidLiquid

Solid

Gas

Observe the phase change diagram. Identify the events that can occur to cause a phase change.

HEAT IS RELEASED

OR

HEAT IS ABSORBED

Substance absorbs heat energy

Melting

Substance GAINS energy

Melting• S L

• Solid ABSORBS heat energy

Substance absorbs heat energy

Melting points of different substances• Iron: 1536ºC• Gold: 1063ºC• Glucose: 150ºC• Urea: 132-134ºC

Identify the phase change represented in the photographs below.

LIQUID SOLID

Substance loses heat energy

Freezing• L S

• Liquid RELEASES heat energy

Substance loses heat energy

Identify the process occurring in the animation.

LIQUID GAS

Substance ABSORBS

energy

Vaporization

• L G

• Liquid ABSORBS heat energy

• Evaporation: occurs on surface of liquid

LIQUID

GASLiquid absorbs heat energy

Boiling points of different substances• Alcohol (Ethanol): 79ºC• Iodine: 184.3ºC• Mercury: 356.9ºC• Olive oil: 300ºC• Jet fuel: 163ºC

Identify the phase change represented in the photograph.

LIQUIDGAS

Substance loses heat energy

Condensation• G L

• Gas RELEASES heat energy

LIQUID

GASGas loses heat energy

Identify the phase change represented in the photograph.

SOLID GAS

Substance ABSORBS

energy

Sublimation• Solid Gas

• Solid ABSORBS energy

Solid

GAS

Solid absorbs heat energy

Mt. Everest loses some snow cover due to common windstorms. Snow is also constantly lost, invisibly, due to sublimation

Moth balls are used when storing clothing and other articles susceptible to damage from mold or moth larvae. Moth balls commonly undergo the process of sublimation. Sublimation is the process in which a solid changes directly to its gaseous phase, skipping the liquid phase.

Humid air to condenses into frost patterns, for example in single-layer window glasses and windshields.

Deposition

SOLIDGAS

Substance LOSES energy

Deposition

• G S

• Gas RELEASES energy https://www.youtube.com/watch?v=Ft2KgtlP8Lk

Solid

GAS

Solid releases heat energy

Let’s summarize…

1. List the different types of phase changes.

2. Explain what happens to heat energy in each phase change.

A B C

1 2

3 4

5

When a liquid becomes a solid, energy

1. does not change

2. is released

3. is absorbed

4. is first absorbed, then released

_______ is the process in which liquid changes to gas below the boiling point.  

1. Sublimation

2. Condensation

3. Evaporation

4. Combustion

On a hot day, the outside of a glass containing a cold drink becomes frosty. When touching the glass, it feels

1. water that has passed through the glass

2. water that has condensed from a gas in the air

3. water that has solidified

4. water that has absorbed energy

The change of a liquid to a solid is called

1. freezing

2. melting

3. sublimation

4. vaporization

When substances go directly from the solid phase to the gas phase, the phase change is called

1. sublimation

2. condensation

3. evaporation

4. vaporization

• Mass number:

137

• Atomic #:

56

• # of neutrons: 137-56

81 neutrons

http://www.youtube.com/watch?v=XaDxwe8l3us&feature=related