Physical Science

Chapter 3Section 3

Changes of State

Fifth change of state is called sublimation

Change of state of a substance is the change of one physical form to another

All changes of state are physical changes In this change, the id of a subs does not

change

Energy and Changes of State II

Particles of a subs move diff depending on the state of the sub

Particles have diff amts of energy when the sub is in diff states Particles in liquid have more E than ice Particles in steam have more E than in

liquid

Melting: Solid to Liquid

A chng of state that happens when you add E to a sub is melting

Melting is the chng of state from a solid to a liquid Adding E to a solid increases the temp

of a solid The temp at which a sub chgs from

a solid to a liquid is the melting pt

More Melting

As temp increases the particles do what?

Melting is an endothermic change because E is gained by the sub as it changes

Freezing: Liquid to Solid

The chg of state from a liquid to a solid is called freezing

Freezing is an exothermic chg because E is removed from the sub as it changes

Evaporation: Liquid to Gas

Evaporation can occur at the SURFACE of a liquid that is below its boiling pt.

Boiling is the change of a liquid to a vapor, or gas, THROUGHOUT the liquid

Boiling occurs when the pressure inside the bubbles, which is called vapor pressure, = the outside pressure on the bubbles, or atmospheric pressure. Temp at which liquid boils is called its boiling

pt

More

Atmospheric pressure is lower at higher elevations.

The higher you go above sea level, the fewer air particles there are above you. The boiling pt in Denver is lower than it

is in Hillsboro.

Condensation: Gas to Liquid

Condensation is the chg of state from a gas to a L. Condensation & evaporation are the REVERSE of each other.

The Condensation Pt of a sub is the temp at which the gas becomes a L

Sublimation: Solid to Gas

This is the chg of state in which a solid changes DlRECTLY into a gas.

This is an endothermic chg cuz E is gained by the sub as it changes.

Chg of Temp v. Chg of State

When sub lose or gain E, 1 of 2 things happens to the sub: its temp chngs or its state chngs.