Phases of MatterPhases of Matter

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The FOUR states of matter are determined by the amount of ………………….…………………. available.

Phases of MatterPhases of Matter

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PLASMAPLASMA+

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The FOUR states of matter are determined by the amount of ENERGYENERGY available.

Phases of Matter

SOLID LIQUID GAS PLASMAPLASMA

POSITION/ ArrangementShape

FORCES

ENERGY/ Movement

Phases of Matter

SOLID LIQUID GAS PLASMAPLASMA

POSITION/ ArrangementShape

FixedRandom Take shape of container

Random Fill any container

ChangingChanging

FORCES Very Strong Weakened Very weakNoneNone

ENERGY/ Movement

Low energy vibrate

Higher Slide over each other

High – Rapid random motion

High – High – particles particles breaking upbreaking up

Phase changesPhase changesThink about what is involved

when a substance has to change from one phase to another. Name each process and describe what needs to happen in terms of:

• position of and spaces between particles

• forces between particles

• energy of particles.

Phase ChangesSolid Liquid Liquid Gas Solid GAS

Process

PARTICLE (positions)

FORCES

ENERGY

Melting (Fusion)When a solid melts the particles

need to undergo a number of changes:

Solid --> Liquid:– the spaces between the particles

increase– The energy of the particles

increases– The forces between the particles are

weakened

Each of these changes requires energy to be put in.

The temperature stays constant because the extra energy is being used to weaken the forces.

Melting

Boiling/(Evaporation)When a liquid boils the particles

need to undergo a number of changes:

Liquid --> Gas:– the spaces between the particles

increase– The energy of the particles

increases– The forces between the particles

are weakened

Each of these changes requires energy to be put in.

The temperature stays constant because the extra energy is being used to weaken the forces.

Boiling/ (Evaporation )

Liquid

Gas

Condensation

Condensing

Energy given offEnergy given off

Liquid

GasWhen a gas condenses:– the spaces between the

particles decrease.– The energy of the particles

decreases (move slower).– The forces between the

particles are strengthened.Each of these changes requires

energy to be taken out. (Given off).

The temperature stays constant because strengthening forces releases energy which replaces that which has been removed.

FreezingWhen a liquid freezes (fuses) the

particles need to undergo a number of changes:

Liquid --> solid:– the spaces between the particles

decrease.– The energy of the particles

decreases (move slower).– The forces between the particles

are strengthened.Each of these changes requires energy

to be taken out. (Given off).

Fusion

Energy taken out Energy taken out

The temperature stays constant because strengthening forces releases energy which replaces that which has been removed.

Phase Change - Snow

Explain why the air is warmer when it snows than when the snow is thawing (melting).

Boiling vs Evaporation

Wind

Water molecules (high energy) escape from the surface of the liquid.

The remaining particles have less energy - lower temperature

ENERGY IS REMOVED FROM THE WATER (Cooling Effect).

All liquids have their own vapour (gas).

This vapour has a pressure which increases with temperature.

When the vapour pressure equals the pressure outside the liquid the liquid boils.

GAS

LIQUID

IN BOILING ENERGY MUST

BE PUT IN.The temperature

of the water does not change as the energy is used to change

the phase.

Phase ChangesSolid Liquid Liquid Gas Solid GAS

Process

PARTICLE (positions)

FORCES

ENERGY

Boiling vs Evaporation

Boiling Evaporation

Similarities • Change water to water vapour• Particles undergo same changes (increase spaces, energy, weaker forces)

Differences • High Temp• Energy put in• Affected by atmospheric pressure

• Low Temp• Energy taken

out.• Not affected by

pressure.

Heating CurveHeating Curve Water

020406080

100

0 200 400 600Time (S)

Tem

pera

ture

(C)

During a phase change the energy is used to overcome forces between the particles and increase the spaces between them - the temperature stays the same so the graph is flat.

Phases Task• Find out the melting point and boiling points of

the following substances.

– Hydrogen oxide (H2O) Mp: 0oC, Bp: 100oC – Nitrogen - gas 80% of the air

• (N2) Mp: -210oC, Bp: -195oC

– Mercury - liquid Mp: -39oC, Bp: 357oC

• What factors can affect the boiling point of water?– Altitude (pressure) - higher (alt) --> lower (bp)– Dissolved substances --> raise the boiling point.