Elements, Compounds, & Mixtures

Matter is made of atoms and groups of bonded atoms called molecules.

Pure substances are made from1 type of atom (element).

Compounds are made from more than 1 type of atom.

Mixtures are substances that are NOT chemically combined.

Which ones are compounds?

When elements combine to make a compound the compound acts differently than the individual elements.

Sodium (Na) is an element Chlorine (Cl) is an element

Sodium is an explosive

metal, and Chlorine is a

poisonous gas. When

they combine to make a

compound we get table

salt (NaCl)

Mixtures

Salt Water is a mixture. The two compounds still retain their properties.

Mixtures can be separated physically.

Compounds can only be separated chemically.

The ocean is a mixture.

Chromatography

Is one way to separate mixtures.

Mikhail Tsvett was the first to use it

He used chromatography to separate plant pigments.

After he separated the pigments then he could identify what each one was.

Synge and Martin

Won the Chemistry Nobel Prize in 1952

Using Paper Chromatography they were able to find insulin.

What is insulin used for?

What is Paper Chromatography?

Chromatography is used to separate complex mixtures.

The Uses of Chromatography

•Industry

•Vitamins

•Hormones

•DNA testing

•Unknown pollutants

•Drug testing

Chromatography separates a mixture by using a solvent to move a solute up a piece of paper.

Solution: The mixture

Solvent: The thing that does the dissolving (example: water)

Solute: The thing that gets dissolved (example:salt)

Paper Chromatography Set-up

Origin Line: The pencil line drawn ½ inch from the bottom

Dot of solute (ink)

Solvent (water)

When the paper absorbs the solvent (water)

The solute (ink)

separates out as it is

dissolved in the water.

Setting up your lab

Why does the origin line NEED to be pencil?

Types of Chromatography

Type of Chromatography Applications in the Real World

Why and What is it

Liquid Chromatography

test water samples to look for pollution,

Used to analyze metal ions and organic compounds in solutions. It uses liquids which may incorporate hydrophilic, insoluble molecules.

Gas Chromatography

detect bombs in airports, identify and quantify such drugs as alcohol, used in forensics to compare fibers found on a victim

Used to analyze metal ions and organic compounds in solutions. It uses liquids which may incorporate hydrophilic, insoluble molecules.

Thin-LayerChromatography

detecting pesticide or insecticide residues in food, also used in forensics to analyze the dye composition of fibers

Uses an absorbent material on flat glass plates. This is a simple and rapid method to check the purity of the organic compound.

Paper Chromatography

separating amino acids and anions, RNA fingerprinting, separating and testing histamines, antibiotics

The most common type of chromatography. The paper is the stationary phase. This uses capillary action to pull the solutes up through the paper and separate the solutes.