Investigation 7: Gas to Solid

December 12 and 13

Warm Up

Explain what happens to margarine particles when it changes from solid to liquid.

Warm Up

• The particles of solid margarine gain KE. They begin to move more and their bonds loosen. When they have enough KE, the particles move as a liquid.

Learning Target

I can explain at the particle level how water vapor changes phases to a solid.

Observations

• Margarine• Wax• Sugar

Melting of Margarine

• Solid changed to liquid• Heat energy transfers to the margarine and

particles gain KE.• They vibrate more and more until they

start to move around and past one another. • When all the particles are moving, the

margarine is melted and now liquid.

Melted Margarine in Cold Water

• What would happen to the particles if melted margarine were put in cold water?– Energy would transfer from the margarine

particles to the cold water, reducing the KE of the particles.

– The particles would slow down, stop moving, and it would change back to a solid.

Wax Particles at 60 Celcius

• What happened to the wax particles in the hot water?– Heat energy transfers to the wax and the particles

gain KE.– They vibrate more and some start to move around

each other causing the wax to get soft.

Sugar Particles at 60 Celcius

• What happened to the sugar particles?– Heat energy transfers to the sugar and the

particles gain KE.– They vibrate more but not enough to change

phases to liquid.

How could we get sugar and wax to change phase into a liquid?

• Increase the KE. • The melting point of sugar and wax are higher

than butter. • Once enough KE is added, the sugar and wax

particles will move more until they are a liquid.

What happens to liquid wax, butter, and sugar if they are placed

in a cool environment?

• The particles would transfer KE to the cool environment.

• If enough KE is transferred, the substances freeze and turn back to a solid.

http://www.brainpop.com/science/matterandchemistry/matterchangingstates/

What happens to the particles when changing from a solid to a liquid?

• The particles gain KE and move around each other until they are moving as a liquid.

What happens if you continue to add KE to the liquid?

• The liquid particles would move faster and faster until the bonds between the particles are broken. The particles will move freely through space as a gas.

What would happen to the gas particles if they were cooled off?

• The gas particles would slow down and come closer together. They would bond and begin to move as a liquid.

When have you seen a gas change to a liquid?

•Breathe on a mirror• Steam on a mirror after a

hot shower•Rain

Gas to Solid, Page 129

If water boils and turns into a gas, where does it go?

Into the air.What is water gas called?

Water vapor.What does water vapor look like?

Nothing. It is invisible.

What can you do to find out if water vapor is present?

Cool it back down to change its state back to liquid so it can be seen.

Water and Ice System

• Observations?• You can see the steam, fog, and dew on the

cup. What are they composed of?• Where did the liquid water come from?

Condensation and Evaporation

Condensation is the process of changing state from gas to liquid. Water vapor particles lose KE. The particles stop flying around as gas and bunch together as liquid.

Condensation and Evaporation

Evaporation is changing state from liquid to gas.Energy transfers to the liquid water, the KE increases. With enough KE, the particles escape the others and fly off as water vapor.

Water and Ice System

• Liquid water to water vapor•Water vapor to liquid water• How can you change the liquid

water to solid water (ice)?

Complete Notebook Page 129

• Work alone• No talking• Start with describing the particles in the hot

water and end with describing the particles in the ice on the cup.

• Word bank: KE, evaporation, energy transfer, phase change, condensation, freezing, liquid water, water vapor, ice

Green Textbook page 42Notebook Page 119

• Correct answers as we review them

1. What causes a substance to change from one phase to another?

Heat. When enough KE has transferred to or from the particles of a substance, the substance will go through one or more phase change.

2. What are the three important things to know about freezing and melting?

1. Substances don’t have to be cold to freeze or hot to melt.

2. Phase is a relationship between the particles in a substance.

3. A substance’s melting temperature is the same as its freezing temperature.

3. Why does liquid water form on the bottom of a cup of ice placed over warm water?

Water vapor rises from the warm water. When the water particles contact a cold surface, energy transfers from the particles to the surface. The water changes phase from gas to liquid.

4. What happens to water particles as a cup of ice melts and then evaporates?

Heat transfers to the water particles in ice which breaks bonds holding the water particles together. Particles start to move over and around one another, the liquid form of water. As more heat transfers to the liquid, more bonds are broken and particles break free and fly through space as individual particles, the gas form of water.

Exit slip

• Explain what would happen to the sugar and wax particles if they were heated more?

• Explain what would happen to sugar and wax particles if they were removed from the heat?

CHAMPSC- NoneH-Raise your handA- Sitting up, recording your answersM-NoneP- All students working on answeringSuccess for all students!

CHAMPSC- NoneH-Raise your hand if you have a question.A- Sitting up, working on quizM-None P- All students sitting quietly correcting quiz.Success for all students!

CHAMPSC- Only at your group.H-Raise your hand if you have a question.A- Sitting up, working on answers. M-None. P- All students working on pages 97 and 99.Success for all students!

CHAMPSC- Only with your group. Only on topic.H- Check in book, notes, and ask your group members. Raise your hand if you have a questionA- Completing lab and table on pg 115.M- NoneP- All students working on lab. Success for all!!!