1. Chemical Reactions

2. Chemical Reactions
Produce new substances by changing the way in which atoms are arranged.
REACTANTS= substances used in a chemical reaction
PRODUCTS= substances formed by chemical reaction

3. Sign #1
Reactants: Cabbage Juice and Vinegar; Cabbage Juice and Baking Soda
Add 10 mL of cabbage juice to 2 test tubes
Add a few drops of vinegar to one test tube
Add one lab scoop of baking soda to another

4. 6 Signs of a Chemical Reaction!
COLOR CHANGE
Substances change color
Color change is a product of two or more reactants
Examples: Rust, leaves changing color, mold

5. Sign #2 Reactants: Baking Soda and Vinegar (Acetic Acid)
10 mL of Vinegar in test tube
1 lab scoop of baking soda
Swirl and observe!

6. 6 Signs of a Chemical Reaction!
FORMATION OF A GAS
Bubbles often appear
Fizzes
A product gas is leaving the reaction mixture
Examples: vinegar + baking soda = carbon dioxide

7. Sign #3 Reactants: Citric Acid and Baking Soda
10 mL Citric acid in test tube
Take temperature
Combine w/ 1 lab scoop of baking soda
Swirl and observe temperature!

8. 6 Signs of a Chemical Reaction!
ENDOTHERMIC REACTION (temperature/energy change)
Chemical bonds break
Energy (heat) is absorbed from surroundings
Substance seems cooler
Examples: cold packs, photosynthesis

9. Sign #4 Reactants: Hydrogen Peroxide and Yeast
10 mL Hydrogen Peroxide in test tube
Take temperature
Combine w/ 1 lab scoop of yeast
Swirl and observe temperature!

10. 6 Signs of a Chemical Reaction!
EXOTHERMIC REACTION (temperature/energy change)
Chemical bonds are made
Energy (heat) is released to surroundings
Substance seems warmer
Examples: fireworks, explosions, hand warmers

11. Sign #5 Reactants: Ammonia and dissolved Epsom Salt 40 mL ammonia
1 tsp epsom salt dissolved in 40 mL hot water
Combine and observe!

12. 6 Signs of a Chemical Reaction!
A PRECIPITATE IS FORMED
A solid that forms when two liquids combine
The solid particles are the product
Examples: Kidney stones, pearls, cheese

13. 6 Signs of a Chemical Reaction!
ODOR
Produces new smells as the reaction occurs
Examples: Rotting, bad breath