1. Chemical Reactions The story

2. Hi there. This is H 2 O. So is this. Meet 2H 2 O

3. They weren’t always so happy.

4. Hmph. You’re out of control Bbbllgghh!!

5. You need me. I’m important. Meet O 2

6. He’s light. He’s fast. He’s crazy! Meet H 2 B-b-b-b-b

7. One day… Hey! Quit it!

8. One day…

9. Chemical Reactions Bonds are broken and new bonds are formed. Bonds in H 2 & O 2 break.

10. Chemical Reactions Bonds are broken and new bonds are formed. New bonds form.

11. Chemical Reactions New substances are formed. 2 gases react Water is formed

12. Parts of a Reaction Reactants: The chemicals you have before the reaction H2H2 That’d be us. Tbtbbhth! H2H2 O2O2

13. Parts of a Reaction Products: The substances created in the reaction H2OH2O H2OH2O

14. Chemical Equation ReactantsProducts Parts of a Reaction

15. Chemical Reactions During chemical reactions atoms are not created or destroyed. They’re just rearranged. 2 oxygen atoms 4 hydrogen atoms 2 oxygen atoms 4 hydrogen atoms

16. How can you tell if a chemical reaction has happened? Let me give you some hints.

17. Is it a chemical reaction? If a gas is produced it might be a chemical reaction. Look for the bubbles!

18. Is it a chemical reaction? If it changes color it might be a chemical reaction. Like iron rusting!

19. Is it a chemical reaction? If it gets hotter it might be a chemical reaction.

20. Is it a chemical reaction? Or…if it gets colder it might be a chemical reaction.

21. Exothermic Reactions Exothermic reactions release energy. These reactions feel hot.

22. Endothermic Reactions Endothermic reactions absorb energy. These reactions feel cold.