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

Paper Chromatography

Chromatography:Separates substances on the basis of differences in solubility in a solvent.

Setup to heat a solution

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

Ring stand

Beaker

Wire gauze

Ring

Bunsen burner

The solution is boiled and steam is driven off.

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

Distillation ApparatusSalt 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

Centrifugation

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

• Separate blood into serum and plasma– Plasma = less dense– Erythrocytes = red blood cells

• Check for anemia (lack of iron)

Water Molecules

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 8

The decomposition of two water molecules.

2 H2O O2 + 2 H2

Electriccurrent

Watermolecules

Diatomic Diatomicoxygen molecule hydrogen molecules+