STATES OF MATTERWhat are different states of matter

and how does matter change state?

4 TYPES OF MATTER• Solid• Liquid• Gas • Plasma

STATES OF MATTER• Based upon particle arrangement• Based upon energy of particles• Based upon distance between particles

SOLIDS

• Very tightly packed• Vibrating in FIXED position• Definite shape and volume

LIQUIDS

Tightly packed BUT far enough apart to

slide over one another Indefinite shape Definite volume

GASES

Very far apart Move freely. Undefined shape Undefined Volume

PLASMA

Ionized gas. Very good conductor

of electricity Affected by magnetic

fields. Indefinite shape Indefinite volume.

• Liquid crystals - rod-shaped molecules that flow like liquid and bend light.

• LCD’s – liquid crystal displays used in watches, thermometers, calculators and laptop computers.

• Amorphous Materials – no form: Not all solids are crystalline.

• The particles in an amorphous solid are not arranged in a regular, repeating pattern - do not form crystals.

OTHER FORMS OF MATTER

WHAT IS A PHASE CHANGE?• A change from one state of

matter to another.• Physical changes because:• Only affects physical appearance, not

chemical make-up• Reversible

MELTING• Solid to a liquid• Molecules speed up,

move farther apart, and absorb heat energy

• What do you think the energy absorbed is being used for?

FREEZING• Liquid to a solid• Molecule slow down,

move closer together and release heat energy.

• What do you think the energy is being released from?

VAPORIZATION (BOILING)• Liquid to gas. It occurs

at the boiling point of matter.

• Molecules speed up, move farther apart, and absorb heat energy.

EVAPORATION• Liquid to a gas on the

surface of a liquid (occurs at all temperatures).

• Molecules speed up, move farther apart, and absorb heat energy.

CONDENSATION• Phase change from a gas

to a liquid.• Molecule slow down,

move closer together and release heat energy.

SUBLIMATION• Solid to a gas.• Molecules speed up,

move farther apart, and absorb heat energy.

DEPOSITION• Gas to a solid.• Molecules slow down,

move closer together and release heat energy.

MELTING & BOILING POINTS• Boiling Point: The temperature at

which a liquid changes into a gas.• Melting Point: The temperature at

which a solid changes into a liquid.• What is a Freezing point?

GRAPHING A PHASE CHANGE

SUMMARY

WHAT HAPPENS DURING A PHASE CHANGE?• During: heat energy is

either absorbed or released.• Endo vs Exo

• Heat energy released:• molecules slow down and move

closer together.• Heat energy absorbed

• molecules speed up and expand.

PHASE CHANGES• When a substance changes states• Requires the input or the removal of heat

energy • Freezing exothermic process = energy released

• Melting = endothermic = energy absorbed

• Enthalpy (H) = the heat energy at constant pressure.

• ∆H – “change” in enthalpy = change in heat released or absorbed

INTERMOLECULAR FORCES• Electrostatic Interactions between particles that

cause them to “stick” together.• Attraction between positive charges and negative charges

• Strongest in solids• Weakest in gases.• During a phase change IMFs are either are being

broken/weakened or strengthened/formed • At room temperature how do you think IMFs

affect the state matter is in?• For example: at RT why do you think O2 is a gas vs. Ethanol is a

liquid?

• During a phase change Temp REMAINS THE SAME

• Only heat energy is added or removed during a phase change.

• Heat of Vaporization - amount of energy absorbed when phase changes from liquid to gas

• Heat of Fusion – the horizontal segment of graph – when a liquid substance becomes a solid.

• Joule (J) = SI unit of energy

HOW DOES ENERGY CHANGE RELATE TO TEMPERATURE CHANGE?

CAN ENERGY INPUT CHANGE WITHOUT CHANGING TEMPERATURE?

What did you observe in your lab?

HELPFUL INFO• Melting point and freezing point are

the same thing. It just depends if the substance is getting hotter or colder.

• During a phase change temperature does not change, but the amount of heat does.

HOW DOES THIS RELATE TO THE BURNS?• Why does steam get ‘hotter’ and what

does ‘hotter’ mean?• What happens when steam hits your skin?• Think about phase change and the

energy…