1. Chemical Reactions Reactions change one or more substances into new substances. [http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_07/FG07_01.JPG]

2. Octane + Oxygen Gas  Carbon Dioxide + Water C 8 H 18 + O 2  CO 2 + H 2 O Written only using chemical formulas…

3. Chemical Equations Reactants are the substances at the beginning of the reaction. Products are the substances at the end of the reaction. Reactants  Products

4. Chemical Equations The arrow (  ) means “produces” or “yields”. Reactions must follow the law of conservation of mass.

5. Chemical Equations The LCM says that matter is not created or destroyed in a reaction, but always stays the same. Example: Formation of Water H 2 + O 2  H 2 O

6. [http://wps.prenhall.com/wps/media/objects/439/449969/Media_Portfolio/Chapter_10/FG10_06.JPG] H 2 + O 2  H 2 O

7. Chemical Equations H 2 + O 2  H 2 O Coefficients can be placed before chemicals to multiply the number of atoms! 2

8. H 2 + O 2  2 H 2 O [http://wps.prenhall.com/wps/media/objects/439/449969/Media_Portfolio/Chapter_10/FG10_06.JPG]

9. Chemical Equations H 2 + O 2  2 H 2 O2

10. [http://wps.prenhall.com/wps/media/objects/439/449969/Media_Portfolio/Chapter_10/FG10_06.JPG] 2 H 2 + O 2  2 H 2 O OK!

11. Chemical Equations H 2 + O 2  H 2 O Started With: “Balanced”: 2H 2 + O 2  2H 2 O What About… H 2 + O 2  H 2 O 2 This is a completely different reaction so it is incorrect!

12. Chemical Equations Example: H 2 + N 2  NH 3

13. [http://wps.prenhall.com/wps/media/objects/439/449969/Media_Portfolio/Chapter_10/FG10_09.JPG] H 2 + N 2  NH 3 H 2 + N 2  2 NH 3 3 H 2 + N 2  2 NH 3 OK!

14. Chemical Equation Symbols Cu(s) + 2 HCl(l)  2 CuCl(aq) + H 2 (g) Phases of matter can be listed after the chemicals…(aq) means aqueous! Other symbols on pg. 740