MixturesMixtures

MixturesMixtures

A physical blend of more than TWO A physical blend of more than TWO SUBSTANCESSUBSTANCES

There are TWO classifications of There are TWO classifications of mixturesmixtures

HOMOGENEOUSHOMOGENEOUS HETEROGENEOUSHETEROGENEOUS

HOMOGENEOUS MIXTURESHOMOGENEOUS MIXTURES

HOMO HOMO – From the Greek word – From the Greek word meaning THE SAMEmeaning THE SAME

Completely uniform distributionCompletely uniform distribution Each sample will contain the same Each sample will contain the same

proportions of the mixtureproportions of the mixture Solutions are examples of Solutions are examples of

HOMOGENEOUS MIXTURESHOMOGENEOUS MIXTURES

SOLUTIONSSOLUTIONS

Place salt in waterPlace salt in water Solid phase added to liquid phaseSolid phase added to liquid phase Homogeneous?Homogeneous? YES! YES! The salt dissolves in the water leading The salt dissolves in the water leading

to a to a UNIFORM DISTRIBUTIONUNIFORM DISTRIBUTION Solutions can be gas/gas, liquid/gas, Solutions can be gas/gas, liquid/gas,

gas/liquid, liquid/liquid, solid/liquid and gas/liquid, liquid/liquid, solid/liquid and solid/solidsolid/solid

EXAMPLESEXAMPLES

G/G ? AIRG/G ? AIR L/G ? Water vapor in air (clouds - L/G ? Water vapor in air (clouds -

localized)localized) G/L? SodaG/L? Soda L/L? Coffee/TeaL/L? Coffee/Tea S/L? anything that dissolves in waterS/L? anything that dissolves in water S/S? SteelS/S? Steel

HETEROGENEOUS MIXTURESHETEROGENEOUS MIXTURES

HETEROHETERO – From the Greek word – From the Greek word meaning differentmeaning different

Not uniform in compositionNot uniform in composition Oil and waterOil and water Heterogeneous?Heterogeneous? YES!YES! The oil will not mix with the water The oil will not mix with the water

creating two phasescreating two phases

A Phase?A Phase?

Any part of a system with uniform Any part of a system with uniform propertiesproperties

Homogeneous Mixtures consist of a Homogeneous Mixtures consist of a single phasesingle phase

Heterogeneous mixtures consist of Heterogeneous mixtures consist of two or more phasestwo or more phases

ExamplesExamples

Lava Lamp – Water Phase/Wax PhaseLava Lamp – Water Phase/Wax Phase Soup – Liquid/Chunky BitsSoup – Liquid/Chunky Bits Burgers – Meat/Bread/Salad/Special Burgers – Meat/Bread/Salad/Special

SauceSauce Your turn – Think of 3 more examples Your turn – Think of 3 more examples

of heterogeneous mixturesof heterogeneous mixtures

Separating MixturesSeparating Mixtures

Some mixtures are easily separated Some mixtures are easily separated by simple physical meansby simple physical means

Burger with no pickle – Just take out Burger with no pickle – Just take out the picklethe pickle

Some mixtures may rely on physical Some mixtures may rely on physical properties to separateproperties to separate

Lets think about a complex Lets think about a complex mixturemixture

Salt and waterSalt and water HomogeneousHomogeneous Salt dissolved in the waterSalt dissolved in the water What can we do to separate this What can we do to separate this

mixture mixture Are there any physical properties we Are there any physical properties we

can make use ofcan make use of

Salt and WaterSalt and Water

Water evaporates at much lower Water evaporates at much lower temperatures than salttemperatures than salt

Heat the mixtureHeat the mixture The water will evaporate, leaving the The water will evaporate, leaving the

saltsalt How could we recover the water?How could we recover the water?

DistillationDistillation

Salt + Water

Heat

Liebig Condenser

Water

•Water is evaporated by the heat•Cooled and condensed in the condenser•Collected in the beaker•The salt will remain in the conical flask as a crystallized solid

More DistillationMore Distillation

What else can we separate with distillation What else can we separate with distillation apparatus?apparatus?

Mixtures of LiquidsMixtures of Liquids

How?How?

We use the physical property of BOILING POINT We use the physical property of BOILING POINT to separate different liquidsto separate different liquids

This type of distillation is called FRACTIONAL This type of distillation is called FRACTIONAL DISTILLATIONDISTILLATION

DistillationDistillationThermometer

Salt + Water

Condenser

CollectionVessel

Heat

ReviewReview

Give five examples of the following:Give five examples of the following:

1.1. Pure substancePure substance

2.2. Homogeneous MixtureHomogeneous Mixture

3.3. Heterogeneous MixtureHeterogeneous Mixture

4.4. SolutionSolution Outline a method for separating Outline a method for separating

components from of your examples for components from of your examples for 2, 3 and 42, 3 and 4

Other Separation MethodsOther Separation Methods

ChromatographyChromatography LiquidLiquid IonIon Size ExclusionSize Exclusion

PrecipitationPrecipitation Solvent Extraction (filtration)Solvent Extraction (filtration)

DEMODEMO

Set up a CHROMATOGRAPHY Experiment Set up a CHROMATOGRAPHY Experiment from the handoutfrom the handout

Refer to the instructions for writing up a labRefer to the instructions for writing up a lab PURPOSE – To see if ink is a mixture or a pure PURPOSE – To see if ink is a mixture or a pure

substancesubstance Analysis and conclusions questionsAnalysis and conclusions questions

What did you observe?What did you observe? How do we classify the ink? Is it a pure substance?How do we classify the ink? Is it a pure substance?