1. Substances, Compounds and Mixtures

2. Main Idea Supporting Facts
The main concepts for this lecture are:
Elements
Compounds
Substances
Mixtures 2

3. Main Idea Supporting Facts
Element
A chemical element is a pure chemical substance that cannot be broken down into a simpler substance. It is made of only one type of atom (we’ll discuss atoms more in the next unit). 3

4. Examples of Elements (SPONCH)
Nitrogen
Sulfur
Carbon
Hydrogen

5. Main Idea Supporting Facts
Compounds
A combination of two or more different elements (they must chemically combine to form a formula) 5

6. Examples of Compounds Water sugar Sodium hypochlorite - Bleach NaClO-
H2O
sugar
C12H22O11

7. Question Time!
Which of the following is a compound?
Copper wire
Frozen water
Pure gold coin
Aluminum Foil

8. Main Idea Supporting Facts
Substance
Matter that has a defined composition.
Also called a pure substance.
Examples are distilled water, table salt, fructose (fruit sugar) 8

9. Main Idea Supporting Facts
Mixtures
A mix of two or more substances.
If the substances experience a physical change, they can be separated by physical means, such as dissolution (to fall out of a solution), separation, etc…
If the substances experience a chemical change, then they cannot be separated via physical means.
There are two types:
Homogeneous
Heterogeneous 9

10. Example of a Mixture being made via a CHEMICAL change
Mentos and Coca-Cola

11. Main Idea Supporting Facts
The mixture is the same throughout. It is also called a solution.
With food, this means each bite is exactly the same as the next bite.
Homogeneous Mixture 11

12. Main Idea Supporting Facts
A mixture that is NOT the same throughout.
In food, this would be items where one bite is different from the next.
Heterogeneous Mixture 12

13. Question Time!
Which of the following is a heterogeneous mixture?
Blood
Chocolate Ice Cream
Pasteurized Milk
Pulp-free Orange juice

14. Main Idea Supporting Facts
Mixtures in chemistry are often in the form of liquids. A solute is an object that is mixed into a larger amount of chemical, called a solvent. It will dissolve into the solvent.
A colloid and suspension are two types of liquid mixtures. Colloids are homogeneous mixtures that do not settle out of solution on their own. Milk an example of one
A suspension is a homogeneous mixture that will have its particles settle out when left alone. Iced Tea and Lemonade would be an example of this
Vocabulary for Liquid Mixtures 14

15. Main Idea Supporting Facts
Some ways to separate mixtures?
Hand separation – If mixture is dry (like sand and seashells), you can pick out the unlike parts by hand.
Filtration – Using a filter system to separate smaller particles from larger ones (like washing of archaeological artifacts to rid them of dirt, silt, clay and sand)
Distillation – boiling a liquid substance so the particles separate out their boiling parts (i.e., how we get gasoline from crude oil)
Centrifugation – spinning a liquid in a small chamber until its components separate out via their densities (i.e., blood centrifugation) 15