1. Matter: Compounds and Mixtures
Chapter 4
Section 1

2. Let’s Review:
Matter is anything that has a mass and takes up space (has a volume).
Matter is made of atoms.
Matter can be either a pure substance, like an element or compound, or a mixture.
Matter has both physical properties and chemical properties that tell us about the substance.

3. Compounds
Compounds are substances made of 2 or more elements that form a molecule.
Molecule - 2 or more atoms bonded together
Examples of common compounds:
Table Salt - NaCl
Oxygen gas – O2
Water – H2O

4. Properties of Compounds
The chemical and physical properties of the compound are DIFFERENT from the properties of the elements that make it up.
Example:
+ =
Sodium Chlorine gas = Table Salt
(Na+) (Cl-) (NaCl)
Metallic Solid Gas Solid
Shiny Yellow White and Dull
Reactive Reactive Non-reactive

5. Properties of Compounds Continued…
Compounds have BONDS between the atoms
It is difficult to separate the parts of a compound because the bonds are not easily broken.
Compounds have chemical formulas to tell you what elements are found in the compound and how many atoms of each element are present.
The chemical formula for water is H2O. There are two atoms of hydrogen and one of oxygen.
If there is 1 atom present, no number is written, but if there are 2 or more atoms present a number is written as a subscript.

6. Kinds of Compounds Compounds can be ionic or covalent
Ionic compounds form by giving away/taking electrons
Covalent compounds form by sharing electrons

7. Mixtures
Mixtures are combinations of 2 or more pure substances or compounds not bonded together
Some common mixtures:
Iced Tea
Dirt
Paint

8. Properties of Mixtures
The chemical and physical properties of a mixture are SIMILAR to the properties of the substances that make it up.
EXAMPLE =
Sugar + Water = Sweetened Water
Crystals Liquid Liquid
Sweet Not sweet Sweet

9. Properties of Mixtures Continued…
There are NO BONDS holding mixtures together.
Mixtures can often be separated easily.
Mixtures can occur in any proportions and DO NOT HAVE A SET FORMULA.

10. Kinds of Mixtures A homogeneous mixture is mixed EVENLY:
water & food coloring
Kool Aid mix & water
A heterogeneous mixture is mixed UNEVENLY
oil & water
sand & rocks.