1. Chemical Reactions 8 th 5.1 Chemical Reactions

2. Chemical Reactions Physical changes- same substance changing form (solid, liquid, gas) Physical changes- same substance changing form (solid, liquid, gas) Chemical changes-formation of a new substance Chemical changes-formation of a new substance Chemical reaction-a process where chemical changes occur Chemical reaction-a process where chemical changes occur Chemical equations-symbols used to describe a reaction Chemical equations-symbols used to describe a reaction

3. 1. Color change 1. Color change 2. Bubbles form 2. Bubbles form 3. Light is emitted 3. Light is emitted 4. Temperature change 4. Temperature change 5. Precipitate forms 5. Precipitate forms

4. Chemical Reactions Reactants-substances that react. Reactants-substances that react. Product-new substances created. Product-new substances created. Chemical formula Chemical formula H 2 + O 2  H 2 O + O H 2 + O 2  H 2 O + O C 2 H 4 O 2 +NaHCO 3 (Reactants)  C 2 H 4 O 2 +NaHCO 3 (Reactants)  NaC 2 H 3 O 2 +H 2 O+CO 2 (Product) NaC 2 H 3 O 2 +H 2 O+CO 2 (Product) 6 CO 2 + 6 H 2 O  C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O  C 6 H 12 O 6 + 6 O 2

5. Chemical Reactions Conservation of Mass-the mass of the reactants always equals the mass of the products Conservation of Mass-the mass of the reactants always equals the mass of the products Endothermic reaction-energy is absorbed (cold) Endothermic reaction-energy is absorbed (cold) Exothermic reaction-energy is released (warm) Exothermic reaction-energy is released (warm)

8. Physical or Chemical Change 1. Making a cake 1. Making a cake 2. Rotting fruit 2. Rotting fruit 3. Water evaporating 3. Water evaporating 4. Soil erosion 4. Soil erosion 5. Boiling an egg 5. Boiling an egg 6. Butter melting 6. Butter melting 7. Soda freezing 7. Soda freezing 8. Making bread 8. Making bread 9. Chopping wood 9. Chopping wood 10. Burning wood 10. Burning wood 11. Chewing food 11. Chewing food 12. Silver tarnishing 12. Silver tarnishing 13. Metal rusting 13. Metal rusting 14. Popcorn popping 14. Popcorn popping