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.

Is one way to separate mixtures. 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 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.