1. Chemical Reactions
Cornell Notes page 139

2. Chemical Properties
Characteristics of a material that can only be determined during a Chemical Reaction
Reactivity
Flammability pH
Oxidation

3. Chemical Reaction
Reactants
Products
The process of substances changing into new substances.
Substances at start of reaction that are changed
New substances made from the reaction (end results).

4. The Law of Conservation of Matter Matter is not created or destroyed.
mass of reactants should equal mass of products!

5. 4 Signs of a Chemical Reaction
Used to identify when a reaction has occurred
Not definite- more signs increase confidence that a reaction has occurred.
Best indicator is that substances have new properties.

6. 4 Signs of a Chemical Reaction
1. Formation of a Gas
Bubbles
Least reliable sign
Ex.) baking soda and vinegar; yeast and hydrogen peroxide.

7. 4 Signs of a Chemical Reaction
2. Formation of a Precipitate
Solid is created when two liquids are mixed
May look like small particles suspended in a liquid.

8. 4 Signs of a Chemical Reaction
3. Unexpected Color Change
When two substances are mixed and an unexpected color occurs.
Ex.) Bleach spilt on colored clothes.

9. 4 Signs of a Chemical Reaction
4. Temperature Change
temperature changes as energy is used or released from the reaction.
Exothermic- heat is released (gets warmer)
Endothermic- heat is absorbed (gets colder)

10. What is a Catalyst?
A substance that starts or speeds up a chemical reaction that is not used or changed in the reaction.
lowers the amount of energy needed in a chemical reaction

11. Oxidation Reactions
Specific type of Chemical Reaction in which a substance reacts with oxygen
Often results in a color change
Apples turn brown
Many metals oxidize, such as iron turning red or copper turning green; we often call this rust.

12. Oxygen reacts with iron to create rust.
The new color is evidence that a chemical reaction has taken place.

13. Oxygen reacts with apples to cause them to brown
Adding citric acid prevents the oxidation reaction.

14. Oxygen reacts with copper to create a green color called verdigris
Many oxidation reactions take time to happen.

15. Burning is an example of a rapid oxidation reaction.
Oxygen is required for burning, the heat and light are evidence that a reaction is taking place.