States of Matter

Chapter 3

States of Matter

Physical forms in which a substance can exist

Matter is always in motion, but the speed of these particles will vary

Solids

Have a definite shape and volume Crystalline: orderly arrangement

Ex. Iron, Diamond, ice Amorphous: no ordered arrangement

Ex. Rubber, wax

Liquids

Change shape, but not volume Surface Tension: force acting on

particles to give a spherical drop/shape Viscosity: liquids resistance to flow

Ex. Honey has a high viscosity versus water

Gas

Change both shape and volume Pressure is the amount of force on a

given area Boyles Law - the volume of a gas

increases as the pressure decreases (at a constant temperature)

Charles Law - the volume of the gas increases as temperature increases

Plasma

Has no shape or volume and particles have broken Ex. Artificial plasma include fluorescent

lights. Natural plasma include lightning during severe weather or the aurora borealis “Northern Lights”

Change of State

A conversion of a substance from one physical form to another Energy of a substance changes,

changing the temperature (measure of the speed of a substances particles)

Transfer of energy is heat

1. Melting

Change of state from solid to liquid Melting points vary with substances and

are characteristic properties Energy is absorbed to overcome particle

attraction

2. Freezing

Change from a liquid to solid Because it’s reverse to melting, freezing

and melting point occur at the same temperature (0oC)

Energy is removed

3. Vaporization

Change from liquid to gas Boiling - vaporization that occurs

throughout a liquid (Ex. Water b.pt. = 100oC)

Evaporation - vaporization that occurs at the surface of a liquid

Pressure affects boiling pointEx. Lower boiling point in Denver, CO

because less atmosphere = less pressure to break apart particles…takes longer to boil pasta!

5. Sublimation

Change from a solid to a gas Ex. Dry ice used in theatres or coolers,

ice cubes in your freezer get smaller over time