The Kinetic Molecular Theory

What is the kinetic molecular theory?

Explains how the phases of matter are different at the molecular level

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• Phases of matter: the different forms that matter can have, including solid, liquid, and gas (vapor)
• Also called ___________________.
• Molecule: a small particle of matter made up of a few atoms bonded together. Can also be called a _____________________.

• Kinetic energy: the energy of motion.
• Volume: the space occupied by matter
• Definite: not variable; unchanging
• Opposite: indefinite

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Imagine These Three Scenarios:

1. The students in this class are sitting in their seats
2. The students in this class are doing a lab experiment.
3. After the bell has rung, the students in this class are going to their next classes.

The students in this class are sitting in their seats.

• What does the shape of the class look like?
• What does the volume of the class look like?
• Does the shape change?
• Does the volume change?
• What type of motion exists?
• Think about the amount of kinetic energy.

The students in this class are doing a lab experiment.

• What does the shape of the class look like?
• What does the volume of the class look like?
• Does the shape change?
• Does the volume change?
• What type of motion exists?
• Think about the amount of kinetic energy.

After the bell has rung, the students in this class are going to their next classes.

• What does the shape of the class look like?
• What does the volume of the class look like?
• Does the shape change?
• Does the volume change?
• What type of motion exists?
• Think about the amount of kinetic energy.

Shape

1. The students in this class are sitting in their seats
• definite
2. The students in this class are doing a lab experiment.
• indefinite
3. After the bell has rung, the students in this class are going to their next classes.
• indefinite

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Volume

1. The students in this class are sitting in their seats
• definite
2. The students in this class are doing a lab experiment.
• definite
3. After the bell has rung, the students in this class are going to their next classes.
• indefinite

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Motion

1. The students in this class are sitting in their seats
• some vibration, particles stay in place
2. The students in this class are doing a lab experiment.
• particles are vibrating and moving past each other
3. After the bell has rung, the students in this class are going to their next classes.
• particles are vibrating, moving, and spreading out

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Kinetic Energy

1. The students in this class are sitting in their seats
• lowest amount of kinetic energy
2. The students in this class are doing a lab experiment.
• medium amount of kinetic energy
3. After the bell has rung, the students in this class are going to their next classes.
• highest amount of kinetic energy

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Talk With Your Partner

• Based on the descriptions of each scenario, label them as solid, liquid, or gas.
• The students in this class are sitting in their seats
• The students in this class are doing a lab experiment.
• After the bell has rung, the students in this class are going to their next classes.

Connection to Chemistry

• Solids behave like the first scenario, students in their seats.

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• Liquids behave like the second scenario, students moving around the room.

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• Gases behave like the third scenario, students going to their next classes.

Glue this on the next blank page. Then, on the next blank page after that, glue the diagrams and add the details.

Solids, Liquids, and Gases