18.1b notes states of matter & phase changes supplement to chapter 18
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18.1b Notes18.1b NotesStates of Matter & Phase States of Matter & Phase
ChangesChangesSupplement to Chapter 18Supplement to Chapter 18
ObjectiveObjective
Describe the phase and energy changes Describe the phase and energy changes associated with phase changes. associated with phase changes.
SolidsSolids Solid – holds a particular shape & Solid – holds a particular shape &
has definite volumehas definite volume Orderliness of particlesOrderliness of particles
Mass: Mass: definitedefinite Volume: Volume: definitedefinite Shape: Shape: definitedefinite Energy: Energy: lowlow
LiquidsLiquids Liquid – does not hold own shape Liquid – does not hold own shape
but does occupy a definite volumebut does occupy a definite volume Flows freely and takes shape of Flows freely and takes shape of
containercontainer Mass: Mass: definitedefinite Volume: Volume: definitedefinite Shape: Shape: shape of containershape of container Energy: Energy: mediummedium
GasesGases Gas – no definite shape or Gas – no definite shape or
volumevolume Expands to fill available volume Expands to fill available volume
of containerof container Mass: Mass: definitedefinite Volume: Volume: can be compressedcan be compressed Shape: Shape: shape of containershape of container Energy: Energy: highhigh
States of MatterStates of MatterSolids Liquids Gases
Mass Definite Definite Definite
Volume Definite Definite Can be Compressed
Shape Definite Shape of container
Shape of Container
Energy Low Medium High
PlasmaPlasma gas-likegas-like made of atoms that have been made of atoms that have been
ripped apart into ions and electronsripped apart into ions and electrons the sun is made of plasma, as is the sun is made of plasma, as is
most of the matter in the universemost of the matter in the universe Plasmas are usually very hot, and Plasmas are usually very hot, and
you can keep them in magnetic you can keep them in magnetic bottlesbottles
Changes in StateChanges in State A transition from one state of matter A transition from one state of matter
to anotherto another Melting: solid to liquidMelting: solid to liquid Freezing: liquid to solidFreezing: liquid to solid Vaporization: liquid to gasVaporization: liquid to gas
Boiling: throughout the liquidBoiling: throughout the liquid Evaporation: surface onlyEvaporation: surface only
Condensation: gas to liquidCondensation: gas to liquid Sublimation: solid to gasSublimation: solid to gas
Changes in StatesChanges in States
Solid
Liquid
Gas
Sublimatio
n
Melting
Freezin
g
Conden
satio
n
Vaporizatio
n
Changing States - MeltingChanging States - Melting
Solid becomes a liquidSolid becomes a liquid
Melting point = temperature at which a Melting point = temperature at which a solid begins to meltsolid begins to melt
Heat of fusion = the amount of energy Heat of fusion = the amount of energy required to change 1 kg of a substance required to change 1 kg of a substance from a solid to a liquid at its melting point from a solid to a liquid at its melting point
FreezingFreezing
Liquid becomes a solidLiquid becomes a solid
Heat of fusion is also the energy released Heat of fusion is also the energy released when a liquid freezeswhen a liquid freezes
The attractive forces are strong enough The attractive forces are strong enough that the particles form an ordered that the particles form an ordered arrangementarrangement
VaporizationVaporization
Liquid becomes a gasLiquid becomes a gas
Evaporation = when vaporization occurs at Evaporation = when vaporization occurs at the surface of a liquid the surface of a liquid Causes the temperature of the liquid to Causes the temperature of the liquid to
decreasedecrease
BoilingBoiling
Second way a Liquid becomes a gasSecond way a Liquid becomes a gas
Occurs throughout the liquid, not just on Occurs throughout the liquid, not just on surfacesurface
Boiling point = temperature at which the Boiling point = temperature at which the pressure of the vapor in the liquid is equal to pressure of the vapor in the liquid is equal to the external pressure acting on its surfacethe external pressure acting on its surface
The heat of vaporization is the amount of The heat of vaporization is the amount of energy required for 1 kg of the liquid at its energy required for 1 kg of the liquid at its boiling point to become a gasboiling point to become a gas
CondensationCondensation
Gas changes to a liquidGas changes to a liquid
The heat of vaporization is also the amount The heat of vaporization is also the amount of energy released during condensationof energy released during condensation