Science 7 Notes 10

Phases of Matter Can you describe the phase Melting changes that matter Freezing undergoes? Vaporization Condensation Sublimation

1. Characteristics of a Phase Change What is necessary for a • It’s a change from one state of matter (solid, liquid, gas) to another. phase change to occur? • Phase changes are physical changes because:

- It only affects physical appearance, not chemical make-up. What are the states of matter? - They are Reversible

2. What happens during a phase change?

 During a phase change, heat energy is either absorbed or released.

What particle  Heat energy is released as molecules slow down and move closer changes are evident when together. heat is added to a substance?  Heat energy is absorbed as molecules speed up and expand.

3. Types of Phase Changes What particle changes are A. Melting evident when heat is removed  Phase change from a solid to a liquid from a substance?  Molecules speed up, move farther apart, and absorb heat

energy

Describe melting.

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Science 7 Notes 10

What states of B. Freezing matter change  Phase Change from a liquid to a solid during freezing?  Molecules slow down, move closer together and release

heat energy. How does molecular movement change during freezing?

What states of matter change during vaporization?

How does molecular movement C. Vaporization/Evaporation change during vaporization?  Phase change from a liquid to a gas.  Vaporization occurs throughout and happens at the boiling point. Evaporation happens on the surface of a liquid at any temperature.  Molecules speed up, move farther apart, and absorb heat energy.

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Science 7 Notes 10

D. Condensation  Phase change from a gas to a liquid.  Molecules slow down, move closer together and release heat energy. E. Sublimation

 Phase change from a solid to a gas.

 Molecules speed up, move farther apart, and absorb heat

energy. F. Deposition

 Phase change from a gas to a solid.  Molecules slow down, move closer together and release heat energy.

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