1. Classifying Matter

2. Let’s start small and work up from there.
Atom – the smallest unit of an element that maintains the properties of the element
The can be physically mixed or chemically joined to make up other forms of matter

3. Pure Substance
A sample of matter, either a single element or a single compound, that has definite chemical and physical properties
Figure 14, Page 22

4. Physical Properties
Characteristic of a substance that does not involve a chemical change
Examples: Density, color, hardness
Does this test change the chemical make-up of the material? No

5. Chemical Property
Characteristic of matter that describes a substance’s ability to participate in chemical reactions
Example: Oxidation, flammability, and combustion
Does this test change the chemical make-up of the material?
Yes

6. Figure 12, page 19

7. Elements A pure substance that contains only one kind of atom
It cannot be separated or broken down into simpler substances by chemical means.
All atoms of the same element have the same atomic number
Elements may bond in different ratios with itself. These are called allotropes.

8. Compounds
A pure substance that is made up of two or more different elements joined by chemical bonds.
They are represented by formulas

9. Molecules
The smallest unit of a substance that keeps all of the physical and chemical properties of that substance.
It can consist of one atom or two or more atoms bonded together
In other words, molecules can be of the same element or of the same compound only

10. All of the following are molecules, but are they compounds or elements?
Br2
H2O O2 O3
C12H22O12
Compound
Element
Element
Compound

11. Mixtures
A combination of two or more substances that are not chemically combined.
Examples are air, ice tea, and even cake batter
The proportions of the substances can vary

12. Mixtures can be homogeneous or heterogeneous
Homogeneous mixtures have a uniform structure or composition throughout
Because of the even distribution, any two samples taken from the same homogenous mixture will have the same proportions of ingredients
Examples: Gasoline, air, and syrup

13. Mixtures can be homogeneous or heterogeneous
Heterogeneous mixtures are not evenly mixed.
Different regions of the same heterogeneous mixture will have different proportions
Examples: Pulpy Orange Juice, chocolate chip cookie dough, and granite.

14. Visuals of Homogeneous and Heterogeneous Mixtures
Figure 19, Page 26

15. Mixtures verses Compounds, How can you tell which is which?
Compounds are two or more elements that are chemically bonded together.
Mixtures are two or more substances physically mixed together, but not chemically joined

16. Therefore
Properties of a mixture reflect the properties of the substances mixed in it; compounds have new properties of their own.
Compounds have definite composition; mixtures composition can vary from mixture to mixture of the same substances

17. In other words,
You can have a mixture of hydrogen gas and oxygen gas in various concentrations, but the compound water, H2O, will always have 2 hydrogen atoms bonded to one oxygen atom.

18. Figure 20, Page 28

19. Classify each of the following as an element, compound, homogeneous mixture, or a heterogeneous mixture
Iron (III) Oxide (Fe2O3)
24 Karat gold
Sugar Water
Ozone
Fizzy Soda
Flat Soda
Compound
Element
Homogeneous Mix
Element
Heterogeneous Mix
Homogeneous Mix

20. Since mixtures are just physically combined, they can be separated.
Separating Mixtures
Since mixtures are just physically combined, they can be separated.

21. Separating Mixtures Some Methods include:
Filtering – separation of a mixture’s components through differences in particle size
Decanting – a fancy term for separating two components by pouring
Distillation – used to separate two liquids based on their differences in boiling points
Magnetism – used to separate magnetic substances
Evaporation – removing a liquid to leave a solid behind
Centrifuge – separates substances of different densities using a fast rotational motion
Chromatography – Separates two substances by using a mobile phase and a stationary phase