Created by Jade Dickey
almost 9 years ago
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Question | Answer |
What is a phase change? | • It is a change from one state of matter (solid, liquid, gas) to another. • Phase changes are physical changes because: - It only affects physical appearance, not chemical make-up. - Reversible |
What happens during a phase change? | • During a phase change, heat energy is either absorbed or released. • Exothermic - Heat energy is released as molecules slow down and move closer together. • Endothermic - Heat energy is absorbed as molecules speed up and expand. |
Melting | Phase change from a solid to a liquid • Molecules speed up, move farther apart, and absorb heat energy |
Freezing | Phase Change from a liquid to a solid • Molecules slow down, move closer together and release heat energy. |
Vaporization (boiling) | Phase change from a liquid to gas. It occurs at the boiling point of matter. • Molecules speed up, move farther apart, and absorb heat energy. |
Evaporation | Phase change from a liquid to a gas on the surface of a liquid (occurs at all temperatures). • Molecules speed up, move farther apart, and absorb heat energy. |
Condensation | Phase change from a gas to a liquid. • Molecules slow down, move closer together and release heat energy. |
Sublimation | Phase change from a solid to a gas. • Molecules speed up, move farther apart, and absorb heat energy. |
Deposition | Phase change from a gas to a solid. • Molecules slow down, move closer together and release heat energy. |
Types of Phase Changes (Photo) | |
Does the temperature of a substance change as the a state change is occurring? | • Things to keep in mind Water freezes/melts and 0 degrees Celsius Water boils/condenses at 100 degrees Celsius Time can also mean energy added or removed |
Water phase change graph (photo) | |
Change of State vs Change in Temperature | When a substance gains or loses energy it must either change temperature or change state but NEVER both. • During state change the added energy causes particles to spread out and go through a phase change • During temperature change the energy is really just making particles move faster |
Melting & Boiling Points | Melting Point: The temperature at which a solid changes into a liquid. • Boiling Point: The temperature at which a liquid changes into a gas. • What is a Freezing point? Compare the freezing and melting points of water. |
Summary (photo) | |
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