Methods of Separating Mixtures

• Magnet

• Filter

• Decant

• Evaporation

• Centrifuge

• Chromatography

• Distillation

Filtration separates

a liquid from a solid

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 40

Mixture ofsolid andliquid Stirring

rod

Filtrate (liquidcomponentof the mixture)

Filter papertraps solid

Funnel

Chromatography

• Tie-dye t-shirt

• Black pen ink

• DNA testing– Tomb of Unknown Soldiers– Crime scene – Paternity testing

Paper Chromatography

Separation by Chromatography

samplemixture

a chromatographic column

stationary phaseselectively absorbs

components

mobile phasesweeps sampledown column

detector

http://antoine.frostburg.edu/chem/senese/101/matter/slides/sld006.htm

Separation by Chromatography

samplemixture

a chromatographic column

stationary phaseselectively absorbs

components

mobile phasesweeps sampledown column

detector

http://antoine.frostburg.edu/chem/senese/101/matter/slides/sld006.htm

Setup to heat a solution

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 42

Ring stand

Beaker

Wire gauze

Ring

Bunsen burner

A Distillation Apparatus

liquid with a soliddissolved in it

thermometer

condenser

tube

distillingflask

pure liquid

receiving flaskhose connected to

cold water faucetDorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 282

The solution is boiled and steam is driven off.

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 39

Salt remains after all water is boiled off.

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 39

No chemical change occurs when salt water is distilled.

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 40

Saltwater solution(homogeneous mixture)

Distillation(physical method)

Salt

Pure water

Separation of a sand-saltwater mixture.

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 40

Separation of Sand from Salt1. Gently break up your salt-crusted sand with a plastic spoon.

Follow this flowchart to make a complete separation.

Salt-crusted

sand.

Dry

sand.

Wetsand.

Weigh themixture.

Decant clearliquid.

Evaporateto

dryness.

Pour intoheat-resistant

container.

Fill with water.

Stir and letsettle 1 minute.

Weighsand.

Calculateweight of

salt.

Repeat3 times?

Yes

No

2. How does this flowchart insure a completeseparation?

Centrifugation

• Spin sample very rapidly: denser materials go to bottom (outside)

• Separate blood into serum and plasma– Serum (clear)– Plasma (contains red blood

cells ‘RBCs’)• Check for anemia (lack of iron)

Blood

RBC’s

Serum

A B C

AFTER

Before