1. Evidence of a Chemical Reaction

2. What is a physical change?
Physical change: a change that occurs that does not change the identity of the substance
Melting ice
Freezing Kool-Aid
Tearing paper
Boiling water

3. What is a chemical change?
Chemical change: a change that occurs causing the identity of the substance to change
Burning
Digesting food
Reacting with other substances
A chemical change is called a chemical reaction

4. Chemical Reaction
A process in which one or more substances, the reactants, are converted to one or more different substances, the products.
A chemical reaction rearranges the atoms of the reactants to create different substances as products

5. What is evidence of a chemical reaction?
Energy Changes
Also called Temperature Changes
Exothermic
Heat is released (feels hot)
Endothermic
Heat is absorbed (feels cold)
Light can be absorbed or released also without a temperature change.

7. What is evidence of a chemical reaction?
Gas Production
Fizzing
Bubbles forming

8. What is evidence of a chemical reaction?
Color Change

9. What is evidence of a chemical reaction?
Formation of a Precipitate
Precipitate
A solid product.

10. What is evidence of a chemical reaction?
One or more new substances are formed
Cannot be easily reversed.

11. Other signs that a Chemical Reaction has occurred…
Fire
Rotting
Decomposition (breaking down)
Baking
Rusting