Chapter 3, Section 3

1. Chapter 3, Section 3 Changes in State

2. Change of State • Change of State: change of a substance from one physical form to another • Change of state happens by: • removing or adding energy! • Which changes the particle speed, the temperature, and finally the state changes!

3. ENDO vs. EXO • Endothermic: Add Energy • To add energy, increase the temperature, the particle movement increases • Exothermic: Remove Energy • To remove energy, decrease the temperature, the particle movement decreases • EX: • Boiling Water. ENDO or EXO • Freeze Water. ENDO or EXO

5. Solid to Liquid? MELTING

6. Melting • Endothermic Process • Adds energy • Temperature increases • Particles move faster • When a certain temperature is reached, the solid will melt (melting point)

7. Liquid to Solid? FREEZING

8. Freezing • Exothermic Process • Removes energy • Temperature decreases • Particles slow down • When the liquid reaches a certain temperature, the liquid will become a solid (freezing point) • Freezing is the reverse of melting

9. Liquid to Gas? EVAPORATION BOILING

10. Evaporation • Occurs at the surface • Endothermic Process • Adds energy • Temperature increases • As the surface reaches a certain temperature, the surface particles change to gas • Happens before the liquid reaches its boiling point

11. Boiling • Occurs throughout the liquid • Endothermic Process • Adds energy • Temperature increases • Particles move faster • Temperature at which a liquid boils is its boiling point

13. Gas to Liquid? CONDENSATION

14. Condensation • Exothermic Process • Remove energy • Temperature decreases • Particle movement decreases • Particles clump together • Temperature at which a gas becomes a liquid is the condensation point • Condensation and vaporization are the reverse of each other

15. Solid to Gas? SUBLIMATION

16. Sublimation • Endothermic Process • Adds energy • Temperature increases • Particle movement increases

17. Comparing Changes of State