AIM: How can we use physical and chemical properties to separate matter. OBJECTIVES: (SWBAT)

1.Identify basic physical properties used to separate samples of mixtures.

2.Understand and describe how these physical properties are used to separate mixtures.

3.Design appropriate methods to separate unknown mixtures.

DO NOW: List 6 physical properties that may be useful in the separation of mixtures.

Electrolysis

*Must add acid catalyst to conduct electricity

*H1+

water oxygen hydrogen

“electro” = electricity “lysis” = to split

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 32

Water

Hydrogengas forms

Oxygengas forms

ElectrodeSource ofdirect current

H2O(l) O2 (g) + 2 H2 (g)

Water hydrogen + oxygen

= hydrogen atom = oxygen atom

Methods of Separating Mixtures

1.What is a filter?

2.What type of mixture is separated by filtration?

3.Define filtrate:

4.Define residue:

5.What physical properties are used to separate substances by filtration?

6.Give examples of 3 mixtures that can be separated by filtration.

1. FILTRATION

Filtration separates

a liquid from a solid

Mixture ofsolid andliquid Stirring

rod

Filtrate (liquidcomponentof the mixture)

Filter papertraps solid

Funnel

Capillary action

• Is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity. The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube, in porous materials such as paper, or in a cell. It occurs because of inter-molecular attractive forces between the liquid and solid surrounding surfaces.

2. CHROMATOGRAPHY1.What physical properties are used to separate mixtures by chromatography?

2.What is capillary action?

3.Why do the components separate on the chromatography paper?

4.Give 2 examples of mixtures that can be separated by this method.

Chromatography

• Tie-dye t-shirt

• Black pen ink

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

Paper Chromatography

The solution is boiled and steam is driven off.

3. DISTILLATION

How can you separate a sand-saltwater mixture.

Separation of a sand-saltwater mixture.

Salt remains after all water is boiled off.

No chemical change occurs when salt water is distilled.

Saltwater solution(homogeneous mixture)

Distillation(physical method)

Salt

Pure water

Setup to heat a solutionRing stand

Beaker

Wire gauze

Ring

Bunsen burner

EVAPORATION