Four Phases or states of Matter

Solid

LiquidGas

Plasma

Solids Constant volumeConstant shapeAtoms or molecules are well ordered into a crystal lattice for most materials

Particles have VIBRATIONAL motion ONLY

Exceptions Glass which is a very slow flowing liquidAmorphous solids have no crystal structure

LiquidsConstant volumeVariable shapeIncompressibleAtoms or molecules loosely attracted to its neighbors, but in close proximity which allows fluid particles Translational (place to place) motion

GasesVariable volumeVariable shapeVERY CompressibleAtoms or molecules are widely separated and have little interaction with each other aside from collisions resulting from their Translational motion

Water is strange!Water expands as it forms a solid. This causes the density of ice to be less than liquid water and, therefore, ice floats in liquid water. Note the structure of liquid water (left) and ice (right). Notice the greater space in the organized crystalline ice structure which is the cause of the expansion. Germanium also does this.

PlasmaTemperature is so high that negative electrons are separated from their positively charged atomic nuclei

No molecules existParticles are electrically chargedFound in Sun, stars, neon bulbs, lightning bolts and Fusion reactors.

Direction of Heat TransferHeat ALWAYS travels from a higher

concentration of energy (high temperature) to a lower concentration of energy (low temperature).

Changing Phases or StatesFor elements, all four states are possible. Compounds can be only solids, liquids or gases

PHASE CHANGES occur when energy content changes

ENERGY: Plasma>Gas>Liquid>Solid

Energy content is the cause of the differences between states or phases at the particle level

Molecular velocity determines TEMPERATURE and STATESlow moving molecules

Means cooler materialIf cool enough, particle

attractions overcome motion and they begin to stick together(freezing)

Fast moving moleculesMeans warmer materialIf warm enough,

particles have enough energy to leave the solid surface to liquid (melting) or the liquid surface to become gaseous (vaporizing)

6 Phase ChangesFreezing (liquid to solid)Melting(solid to liquid)Vaporization (evaporation or boiling)(liquid to gas)

Condensation(gas to liquid)Sublimation(solid to gas- skip liquid)

Deposition(gas to solid- skip liquid)

Melting and FreezingChanges between liquid and solidFreezing is the opposite of meltingMelting - Attractions between solid particles break when energy is added and vibrations increase until they escape into liquid state

Freezing - Particles move slowly enough that attractions can pull particles together to form solid

VaporizingLiquid particles break the attractions of neighboring particles and travel up into the gaseous layer Evaporation- only particles near the surface have enough energy (traveling fast enough) to break the attractions

Boiling – particles throughout the liquid are traveling fast enough to form bubbles with higher pressure than outside conditions. Boiling Point

Evaporation – occurs only from the surface

Evaporation-surface particles onlyOnly particles near the surface have enough energy to become a gas

Liquid particles take energy from the liquid to enter gaseous state which cools the liquid

The gas layer can also cool because of the influx of slower moving gas particles

Boiling –any particle in the sample has enough energy to travel fast enough to exit the liquid phase

Evaporation (are you sure?)

Condensation

CondensationThe opposite of evaporationInteraction of high energy particles with a cooler surface to form liquid

Evaporation and Condensation occur usually on the SURFACE

Gas particles release heat to rejoin the liquid (Exothermic)

SublimationParticles going directly from

solid state to gaseous state.Dry Ice is a good example: Don’t touch, use gloves -78˚C - Sublimation point which is 115˚colder than you

Extended contact = Frost bite

Dry Ice NEVER meltsSolids that smell usually do

so because of Sublimation: Chocolate particles enter your nose

DepositionHot gaseous atoms

forming a layer of solid on a cooler surface: manmade Diamonds are gaseous Carbon on a seed crystal

Can be used to form a layer of thin expensive metal on cheap metal base

Energy and Phase Change

T

Time

Adding heat at a constant rate

Melting

Boiling

Viscosity is related to flow rateLow Viscosity – material can flow rapidly

Water and Alcohol have low viscosity

High Viscosity – material flows slowlyMotor oil, lava, molasses, honey

all have high viscosity

Pressure

Boyle’s Law Pressure vs Volume Relationship

P1 x V1 = P2 x V2 Original New

Decrease the volume of a gas causes a higher pressure.

Increase the Volume of a gas causes a lower pressure. Indirect Relationship

Boyle’s Law Sample Problem

Charles’ Law = Volume vs Temperature

Charles’ Law Sample problem

Graphing Reasons and Rules

Purpose: To find how variables relateX-axis: Independent variable (manipulated)Y-axis: Dependent variable (responding)Slope = rise/run = rate of changeUse = Predicting values that were previously

unknownGraphs MUST have TITLESGraphs MUST have Labels

X-axis IndependentY-axis Dependent

Graphing OutcomesDirectly proportional : A is up & B is up

Indirectly proportional : A is up but B is down

Straight line graph: varying at a constant rate

Curved line graph: varying at a changing rate