Phase Changes

“It’s just a phase”

States of Matter

Solid, liquid and gas (plasma)Changes between states are

called “phase changes”Caused by a change of heat or

pressureHEAT and TEMPERATURE are

not the same thing

Temperature

Measures the average kinetic energy of the particles in a substance.

Is measured in Celsius or Kelvin.Kinetic energy is directly related

to the speed of the molecules.The faster the

particles/molecules are moving the higher the temperature.

Heat

Heat is a measure of energy (Joules).

HEAT and TEMPERATURE are not the same thing.

Ex. A cold Lake Superior has more heat energy than a boiling pot of water.

For our class, higher temperature means more heat.

STATES OF MATTER

Solids

Molecules are tightly packed together.

High potential energy – more bonds.

Particles vibrate in place.Very Dense.Not easily compressed.Definite shape and volume.

LiquidsParticles are not so tightly

packed (liquids flow and can be poured).

Medium potential energy.Definite volumeIndefinite shape (takes shape of

container)

GasesParticles spread out

as the container will allow.

High kinetic energy, particles are moving very quickly

Can be compressedIndefinite volume and

indefinite shape

Phase Changes

When a substance changes states.Requires the input or the removal

of energy or change in pressure.During a phase change the

temperature does not change, but the amount of energy does.

PH

AS

E C

HA

NG

ES

EN

ER

GY

CH

AN

GE

S

Sublimation

Transformation of a substance to a gas from a solid state with no liquid transition.

Dry Ice does this.

Deposition

When a gas transforms into a solid without transitioning through a liquid state.

Ex. Frost forming on windows.