Chapter 3, Section 3 Changes in State

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!

ENDO vs. EXO Endothermic: Add Energy Exothermic: Remove Energy EX: 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

Solid to Liquid? MELTING

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

Liquid to Solid? FREEZING

Freezing Exothermic Process Freezing is the reverse of melting 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

Liquid to Gas? EVAPORATION BOILING

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

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

Gas to Liquid? CONDENSATION

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

Solid to Gas? SUBLIMATION

Sublimation Endothermic Process Adds energy Temperature increases Particle movement increases

Comparing Changes of State