UNIT: THERMAL ENERGY AND STATES OF MATTER

I THE FOUR STATES OF MATTER ARE:

SOLID

LIQUID

GAS

PLASMA

In a plasma, the particles (atoms and molecules) have been torn apart—the electrons jump around—very excited!

II THE KINETIC THEORY OF MATTER

A. (helps to explain why matter behaves the way it does)

B. Main points:

1. all matter is made of particles (atoms/molecules)

2. the particles are always in motion

3. the higher the temperature, the faster they move

4. at same temp, more massive move slower

III SOLIDS (See chart—comparison of 3 states of matter)

A. CRYSTALINE SOLIDS

Solids in which the atoms are arranged in a regular, repeating pattern.

Regular—some sort of order

Repeating—happens over and over

KEY IDEA: What we see on the outside depends on how the atoms pack together.

B. AMORPHOUS SOLIDS (Gk. a = “without” morphe = “form”

Solids in which there in NO crystal structure.

Ex: silly putty

LAB: CRYSTAL GROWTH

LAB: POLYMER LAB

IVLIQUIDS (see comparison chart)

VISCOSITY—a liquid’s resistance to flow. (how gooey or runny something is)

More viscous—gooey

Less viscous—runny

HOMEWORK: VISCOSITY

CLASS ACTIVITY: VISCOSITY STATIONS

V GASES

Gases, unlike some students, obey rules of behavior (their behavior is predictable)

A. Boyle’s Law

Formal: volume and pressure are inversely related.

Informal: the more you squeeze, the smaller it gets.

The less you squeeze, the bigger it gets.

Ex: balloon in vacuum chamber

B. Charles’ Law

Formal: temperature and volume and directly related.

Informal: hot gas spreads out Ex. Soap in microwave

Cold gas shrinks (balloon in refrigerator)

C. Gay- Lussac’s Law

Formal: Temperature and pressure are directly related

Informal: If you squeeze gas, it gets hot (fire syringe)

If you release pressure, it feels cold (air leaving tire)

D. APPLICATIONS OF THE GAS LAWS

1. The hot air balloon

VI CHANGES OF STATE:

Any substance can change state if we add or take away enough energy.

All pure substances have known melting (freezing) and boiling (condensation) points— temperatures at which they change state.

Temperature is a measure of the average kinetic energy of a substance. In other words, when we heat some thing so the temperature rises, the particles making it up are moving faster and faster.

a. melting—solid to liquid

b. vaporization—(liquid to gas)

evaporation—at the surface of the liquid

boiling—within the liquid itself

c. condensation—gas to liquid

d. freezing—liquid to solid

e. sublimation—from solid directly to gas

LAB—PHASE CHANGES OF WATER

(PHASE CHANGES #1)

LAB—PHASE CHANGES #

(PHASE CHANGES OF SULFUR)