1. Changes of State
Chapter 3 Section 3

2. Changing States Caused By: removing or adding thermal energy
a substance can lose or absorb thermal energy
its temperature changes
the speed of its particles changes
and the state changes

3. Temperature
Not all particles in a sample of matter have the same amount of energy
Temperature: the average kinetic energy of particles in a substance
(more kinetic energy = higher temp.)
Example --->

4. Thermal Energy & Heat Thermal Energy Heat
Is the total energy of the particles in a substance
Heat
movement of thermal energy from a warmer substance to cooler one (always w → c)
heating →
↑ thermal energy
↑ motion of particles
↑ temp

5. Changing Energy Adding Energy Removing Energy
endothermic – a reaction in matter in which energy is absorbed (melting is endothermic)
temperature increases
exothermic - a reaction in matter in which energy is released (freezing is endothermic)
temperature decreases

6. Changes of State Melting Freezing
freezing: change from a liquid to a solid
freezing point: the temp. where a substance changes from liquid to solid
melting: change from a solid to a liquid
melting point: the temp. where a substance changes from solid to liquid
Freezing & melting points of a substance are the same
[ex. freezing & melting point of water is 32 ̊F or 0 ̊C]

7. Changes of State Vaporization Condensation
vaporization: change from a liquid to a gas
2 Types:
boiling: occurs below a liquid’s surface
boiling point: the temp. where a substance begins to boil
evaporation: occurs at a liquid’s surface
condensation: change from a gas to a liquid

8. Changes of State Sublimation Deposition
sublimation - change from a solid directly into a gas
deposition: change from a gas directly into a solid

9. Changes of State

10. Changes of State