1. Chapter 2
2.1 Classifying Matter

2. 2.1 Classifying Matter Examples:
___________-Matter that always has exactly the same composition. There is a fixed, uniform composition.
Substances can be classified into two categories:
Elements
A substance that cannot be broken down into simpler substances. There are just over _____elements.
_____- The smallest particle of an element.
An element has a______composition because it contains only one type of atom.
No two elements contain the ___________of atom.
Examples:

3. Pure Substances Con’t. Compounds
A substance that is made from two or more _______ substances and can be broken down into those simpler substances.
The ___________ of a compound differ from those of the substances from which it is made.
A compound always contains two or more elements joined in a _________________.

4. Mixtures
Mixtures tend to retain _______of the properties of their individual substances.
The properties of a mixture can vary because the composition of a mixture is ____fixed.
________________Mixtures - The parts of the mixture are noticeably different from one another. Examples: salads, salsa

5. Mixtures
Homogeneous Mixtures - The substances are so _________________that it is difficult to distinguish one substance in the mixture from another.
Examples:

6. Solutions, Suspensions, and Colloids

7. Solutions, Suspensions, and Colloids
Based on the size of its largest particles, a mixture can be classified as a _________, ____________, or ______________.
Solution- Substances dissolve and form a ______________ mixture.
Examples:
Suspensions- Heterogeneous mixture that separates into ______ over time.

8. Solutions, Suspensions, & Colloids
Colloids- Contains some particles that are _________ in size between the small particles of solutions and the large particles of suspensions. Colloids will not separate and _____ be filtered. However, colloids will scatter light. (_____________)
Example:

9. Section 2.2 Physical Properties
Physical property- Any characteristic of a material that can be ______________ without changing the ______________of the substance in the material.
Examples: viscosity, conductivity, malleability, hardness, ____________, boiling point, and____________.

10. Physical Properties
_________- The tendency of a liquid to keep from flowing. A resistance to flowing.
Example: _______ has a high viscosity.
Conductivity- A material’s ability to allow _____ to flow.
Example: _________over a stove.
Materials with a high conductivity are called _________. They are also a good conductor of electricity as well. Wood is a _______ conductor.

11. Physical Properties
Malleability- The ability of a solid to be _____________________without shattering.
Example: Most__________can be made into coins or foil.
Because gold is both malleable and beautiful, it is often used to make jewelry. These ancient gold medallions were made to form a necklace

12. Physical Properties
 Hardness- One way to compare harness of two materials is to see which of the materials can _______ the other. Stainless steel knife blades can scratch ______. _______ is the hardest known material.
This Tlingit carver is using an adze to carve a canoe from Western red cedar. Red cedar is a relatively soft wood

13. Physical Properties
Melting Point- Temperature at which a substance changes from a ___________. Example: Ice melts because the melting point of water is 0ºC (32ºF).
 Boiling Point- Temperature at which a substance changes from a _____________or vapor.
The table lists the melting points and boiling points for several substances.

14. Physical Properties
 Density- ________of the ______ of a substance to its _____. This can be used to test the purity of a substance.
Examples: ________ has a density of g/cm3.

15. Using Physical Properties
Physical properties are used to _________ a material, to _______a material for a specific purpose, or to__________the substances in a mixture.
Using properties to identify materials
First, decide which properties to____
Second, do tests on the ________sample
Third, compare results with a ______ sample
(This is used in crime scene investigations)
Using properties to choose materials
Properties determine which materials are _______ for which uses. Example: shoelaces wouldn’t be made from______ wood.

16. Using Physical Properties
Using properties to separate mixtures
__________ and __________ are two common separation methods.
Filtration- A process that separates materials based on the _____ of their particles. Example: brewing coffee
Distillation- A process that separates the substances in a solution based on their ________________.
Example: Separate freshwater from seawater.

17. Recognizing Physical Changes
Physical change- Occurs when some of the ________ of a material change, but the substances in the material remain the ______. Examples:
Braiding hair and cutting hair are examples of physical changes. Braiding is a reversible change. Cutting cannot be reversed

18. 2.3 Chemical Properties
Chemical property- Any ability to produce a change on the __________ of matter. 
Chemical properties can only be observed when the substances in a sample of matter are changing into ________________.
Examples:

19. Chemical Properties
Flammability- A material’s ability to ____ in the presence of oxygen. Examples: Anything that can be used as a _____. _______________.
Reactivity- Describes how readily a substance __________ chemically with other _______. Example: Iron with oxygen and water will form _____ if you leave your bike out in the rain.

20. Recognizing a Chemical Change
Chemical change- Occurs when a substance ______ and forms one or more ___ substances. Examples: baking cakes, food digesting.
Three common types of evidence for a chemical change are a change in ______, production of a _____, and formation of a ______________.

21. Evidence for a Chemical Change
Color Change
Silver bracelets will _______. (tarnish)
Matches _____ and turn ________.
Copper roofs turn _____.(patina)

22. Evidence for a Chemical Change
Production of a gas
Mixing vinegar with baking soda (_____________ gas)
Cakes have gas _______ in it

23. Evidence for a Chemical Change
Formation of a precipitate
Precipitate- _____ form and separate from a _______ mixture
_______ of milk- adding lemon juice

24. Is a Change Chemical or Physical?
Sometimes gas bubbles or color change is not a chemical change. You must ask yourself: Are _______ substances present ________the change takes place.
When matter undergoes a chemical change, the ________ of the matter changes. When matter undergoes a physical change, the composition of the matter _______________.
A blacksmith uses a hammer to shape a horseshoe that has been heated. Although the color of the iron horseshoe changes, ______________change is occurring