7.2.2-Changes of State-7.PS.1.3

​7.2.2-Changes in State
7.PS.1.3-Develop a model to explain how changes to a system can explained by changes in temperature and/or pressure and the effect of those changes on particle motion and/or spatial arrangement.

By Jessica Freeman

7.2.2-Objectives:

Students will describe cause and effect relationships related to:
-the role thermal energy plays in particle motion
-the role thermal energy plays in changes of state
Students will use text information to explain:
how pressure affects a change of state from a liquid to a gas.
-Students will develop and use models to describe:
-what happens to particles of matter during changes of state between solids, liquids, and gases.

Multiple Choice

Kinetic energy is what type of energy?

• chemical

• electric

• motion

• sound

Multiple Choice

The total kinetic energy of the tiny particles that make up matter.

• Thermal Energy

• Energy Transfer

• Temperature

• Heat

Multiple Choice

Temperature is the __________ _________ energy of moving particles

• average potential

• average kinetic

• total potential

• total kinetic

Multiple Choice

Which model is demonstrating what molecules in a solid look like?

Multiple Choice

Which model is demonstrating what molecules in a liquid look like?

Multiple Choice

Which model is demonstrating what molecules in a gas look like?

Multiple Choice

In what state of matter is kinetic energy the highest most likely?

• Solid

• Liquid

• Gas

Multiple Choice

What happens to particles as they heat up?

• They slow down
• Nothing
• They don't move
• They speed up

Multiple Choice

Cold things often have a _________ kinetic energy because_______

• lower; particles are moving around less

• lower; particles are moving around more

• higher; particles are moving around the same

• higher; particles do not move

Multiple Choice

As temperature increases, molecules _____________

• move slower

• move the same

• move faster

• stop moving

Multiple Choice

What device do we use to measure temperature?

• Microscope

• Ruler

• Speedometer

• Thermometer

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Changes of state- summary

• change of state

• a physical change
• No chemical reaction.

• Changes of state

• melting, freezing, evaporation,

condensation, and sublimation

• All change of state involves gain or loss of

energy

• Reversible

Multiple Choice

What is the main cause of any change of state?

• Gaining thermal energy

• Thermal energy stays the same

• Gaining or losing thermal energy

• Losing thermal energy

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Match

Match the term with the their proper definition

• Solid

• Liquid

• Gas

Fixed shape and volume.

No fixed shape but a fixed volume.

No fixed shape or size

• Fixed shape and volume.

• No fixed shape but a fixed volume.

• No fixed shape or size

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Melting: Solid to Liquid

•

add heat energy to
sold

•

• melting point- temp.

of change from a
solid to a liquid

• Item

• Item

• Item

Multiple Choice

For a solid to change to a liquid, heat must be __________ .

• Added

• Removed

Multiple Choice

What is the melting point of water?

• 212°C
• 100°C
• 32°C
• 0°C

Multiple Choice

Which number is melting?

• 8

• 9

• 10

• 11

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Evaporation
• Evaporation is the change of

state from a liquid to a gas.

•

Match

Match the arrangement to the state of matter

Solid

Gas

Liquid

Plasma

• Solid

• Gas

• Liquid

• Plasma

Multiple Choice

A change of state from a liquid to gas is called....

• Melting
• Freezing
• Evaporation

Multiple Choice

When you add or remove heat to an object, you are adding or removing _________.

• Mass

• Energy

• Volume

• Matter

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Freezing: Liquid to Solid

• the change of state
From a liquid to a solid.

• Freezing point- temperature at which
• a liquid changes into a solid

• For a liquid to freeze, energy must be

removed from the liquid to slow the
movement of the particles.

Multiple Choice

If you have a sample of water that is 44 °C, what state is it in?

• solid

• liquid

• gas

Multiple Choice

Taking energy away from a substance will make its particles move

• more slowly
• more quickly
• at the same speed

Multiple Choice

Which of the following describes the process of freezing?

• Freezing occurs when the temperature of a substance drops to zero degrees Celsius.
• Freezing occurs when the particles of a solid vibrate so fast that they break free.
• Freezing occurs when the temperature drops enough that a gas turns into a solid.
• Freezing occurs when the particles in a liquid slow down and take fixed positions.

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Boiling

change of a liquid to a vapor, or gas.
Boiling point - temperature at which this
change happens

Water boils
more easily
if the atmospheric
pressure is lower.

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Boiling
Point

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Condensation: Gas to Liquid

energy must be removed to slow the

movement of the particles.

• Condensation and evap. are reverse of each

other.

• condensation point- temp. when gas becomes

liquid.

•

Multiple Choice

Which number is condensation?

• 8

• 9

• 10

• 11

Multiple Choice

A change of state from a liquid to a solid is called....

• Melting
• Freezing
• Evaporation

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Sublimation: Solid directly to Gas

particles must go from being very tightly packed to
being spread far apart.

solid must gain energy for particles to overcome their
attractions.

Multiple Choice

Dry ice is an example of what phase change.

• freezing

• melting

• vaporization/boiling

• sublimation

Multiple Choice

Do particles (or the atoms) in a substance ever stop moving?!

• No

• Yes

Multiple Choice

When a substance changes from a liquid to a solid, this is called...

• Melting

• Evaporation

• Condensation

• Freezing

Multiple Choice

When surface particles of a solid gain enough energy that they form a gas.

• melting point

• evaporation

• condensation

• sublimation

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Sublimation- Other Examples

Mothball- Napthalene and
camphor - (Vick's vap-o-rub

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Temperature and Changes of State

• When a substance is undergoing a

change of state, its temperature
does not change until the change of
state is complete.

• E.g. the temp of a water won’t rise

above zero C until all the ice is
melted.

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Explanation Slide...

​

Multiple Choice

Condensation happens when a gas gets...

• hotter

• cooler

Multiple Choice

On a hot, humid summer day drops of water form on a can of cold soda. What process caused this to happen?

• condensation

• freezing

• vaporization

• deposition

Multiple Choice

Vaporization that tales place only on the surface of a liquid is called?

• evaporation

• vaporization

• condensation

• boiling

Multiple Choice

Which number is condensation?

• 8

• 9

• 10

• 11

Multiple Choice

What phase of matter exists in part C of the graph?

• Gas

• Liquid

• Solid

• Plasma

Multiple Choice

What phase of matter exists in part D of the graph?

• Gas

• Liquid

• Solid

• Plasma

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Specific Heat

the amount of energy required to raise the
temperature of 1 gram of a substance by 1 °
C.

different substances have diff. specific heats
b/c size, mass, attractions, and
arrangements of their atoms or molecules
are different.

Changes of State that Require Energy

• Melting is the change in state from a solid to a liquid.

• Evaporation is the change in state from a liquid to a gas. Boiling is evaporation that happens throughout a liquid at a specific temperature and pressure.

• Sublimation is the change in state from a solid to a gas. Ex. Dry ice changes to a gas at room temperature.

Changes of State that Release Energy

• Condensation is the change in state from a gas to a liquid. Condensation often happens when a gas touches a cool surface

• Condensation point is the temperature at which a gas becomes a liquid.

• Freezing is the change in state from a liquid to a solid. The temperature at which a substance freezes is its freezing point (same as its melting point)

What Happens to Temperature During Changes of State

• When a substance loses or gains energy, either its temperature changes or its state changes. These two changes do not happen at the same time.

• The temperature of a substance does not change during a change of state.

Multiple Choice

What happens to the temperature of a substance during a change of state?

• The temperature of a substance does not change

• The temperature of a substance does change

What Happens to Mass During Physical and Chemical Changes?

• During a chemical or physical change, mass cannot be created or destroyed.

• This can be described as the law of conservation of mass.

Open Ended

What does the law of conservation of mass state?

What Happens to Energy During Chemical and Physical Changes?

• Just like mass, energy cannot be created or destroyed during a physical or chemical change.

• This is known as the law of conservation of energy.

• The total amount of energy before the change must equal the total amount of energy after the change.

Open Ended

What does the law of conservation of energy state?

Multiple Choice

Which type of change is boiling?

• endothermic

• exothermic

• timing

• thermal

Multiple Choice

You see a puddle of water first thing in the morning. It is gone after the sun shines on it all day. What phase change occured?

• boiling (vaporization)

• evaporation (vaporization)

• melting

• freezing

Multiple Choice

What is it called when a solid goes directly to a gas?

• freezing

• vaporization

• condensation

• sublimation

Multiple Choice

What type of change is sublimation?

• endothermic

• exothermic

• thermal

• timing