Creating Compounds

What are elements, compounds & mixtures?

• An element is the smallest part of a substance (matter) that still retains all the properties of that substance.– Is pure

• A compound is two or more substances chemically combined, very difficult to separate, has new chemical & physical properties.– Can be pure

• A mixture is two or more substances physically combined, easily separated, no change in physical or chemical properties.– By defintion is not pure

Don’t forget…

• Atoms are the smallest part of an element.• Molecules are the smallest part of a

compound.• Mixtures can be made up of elements,

compounds, or both.• Symbols represent elements.• Formulas represent compounds.

Atoms combine

• To fill their outermost shell with 8 electrons• To become more stable• To create compounds• By sharing, gaining or losing electrons.

Remember the Kinetic Theory of Matter?

• All atoms are in constant, random motion all the time.• Atoms make up compounds, so

compounds are also in motion all the time.

In fact,

•elements combine to form all known living and non-living substances.

Examples you should know

• table salt, vinegar, water, baking soda, lye (drano®), sugar (glucose), gasoline, carbon dioxide, bleach, oxygen and DNA(deoxyribonucleic acid) to name a few…

Some Formulas you should know…Compound FormulaWater H20Salt NaClSugar (glucose) C6H12O6

Carbon Dioxide CO2

Vinegar CH3C00H

DNA is a complex molecule• Made of three parts: –a phosphate group–a sugar group–one of four types of nitrogen bases• Adenine (A), thymine (T), Guanine (G) and

cytosine (C).• To form a strand of DNA, nucleotides are linked

into chains, with the phosphate and sugar groups alternating.

Let’s draw some diagrams…

Water

Water molecule Lewis dot diagram of a water molecule

Let’s take a closer look…Water

• odorless, colorless liquid

• density: 1 g/cm3

• Boiling Point: 100 °C

Hydrogen• Odorless,

colorless, highly flammable

gas • Density : .088 g/cm3

• boiling point: -252.87 ˚C

Oxygen• Odorless,

colorless, tasteless gas

• Density: 1.495 g/cm3

• Boiling point : -189˚C

Carbon dioxide

Let’s take a closer look…Carbon Dioxide

• Colorless gas

• Density: .0019 g/cm3

• Boiling Point: -78 °C

Carbon

• Black or colorless solid

• Density : 2.27 g/cm3

• Boiling point : 4027 ˚C

Oxygen

• Odorless, colorless, tasteless gas

• Density: 1.495 g/cm3

• Boiling point : -189˚C

Table Salt

Let’s take a closer look…Salt

• White, crystalline solid

• Used as a flavoring and a preservative

• Density: 2.16g/cm3

• Boiling Point: 1413 ˚C

Sodium• Soft, silvery-

white metal solid

• Reacts violently with water

• Density: .968 g/cm3

• Boiling Point: 883˚C

Chlorine

• Yellow-green poisonous gas• Used as a

disinfectant• Density:

2.03 g/cm3

• Boiling Point: -34 ˚C

In conclusion…•Compounds have properties

that are different from the elements that make them up.

Vinegar

Sugar

Baking Soda

Compounds that contain carbon are called . . .

• Organic compounds• Have a special branch of chemistry to

study them: Organic chemistry