1. CHEMICAL REACTION NOTES

2. Chemical equations are short, easy ways to write what happened during a chemical reaction.

3. Reaction of sulfuric acid and sugar. The acid dehydrates the sugar forming a pillar of carbon (black) and steam. Click on the pic! C 12 H 22 O 11 + H 2 SO 4 2C + 11H 2 O

4. Example: Two hydrogen atoms combine with one oxygen atom to form a water molecule can be written like this: 2H 2 + O 2 2H 2 O

5. Chemical equations summarize the changes in a reaction. They tell you the substances that you started with and the substances that you get at the end. Chemical equations tell a story about what happened in a reaction.

6. The substances that you start with are called reactants. They are at the beginning of the story.... "Once upon a time...."

7. The substances that you get at the end are products. They are at the end of the story.... "happily ever after"

8. In a chemical equation, the + sign is read as "reacts with" and the arrow is read as "produces“ or “turns into”.

9. reactant + reactant product Fe and S are the reactants; FeS is the product. Fe + S FeS turns into

10. Fe + S FeS +

11. Numbers in front of the formulas are coefficients, indicating the number of molecules of each kind involved in the reaction. Coefficients of 1 are never written - they are understood.

12. Numbers to the lower right of chemical symbols in a formula are subscripts, indicating the specific number of atoms of the element found in the substance. Subscripts of 1 are never written - they are understood.

13. Let's watch some videos of some more chemical reactions. (click here)

14. LAW OF CONSERVATION OF MATTER The law of conservation of matter states that during a chemical reaction, matter is not created or destroyed. This means that the number of elements that you start with in the reactants has to equal the number of elements you end up with in the products. The elements rearrange to form new things.

15. LAW OF CONSERVATION OF MATTER The elements rearrange to form new things.

16. Example: If you measured the ash left from a wood fire, it wouldn’t have the same mass as the wood that had been burned. BUT, much of it escaped into the air as carbon dioxide gas and water vapor. If you could trap these gases, weigh them, and then add the gas weight to the ash weight, it would equal the weight of the wood!! The number of elements you start with in the wood would equal the number of elements you have in the ash and gas. The elements were rearranged into new things.

17. BrainPop Law of Conservation of Matter

18. N 2 + 3H 2 2NH 3 The reactants and products combined to form a new compound. If you count the number of elements on each side of the arrow, they are the same even though they have made something NEW.

19. Let’s take a look at the following chemical equation: C + H 2 O CO + H 2 What are the reactants? _______ and ________ What are the products? _______ and _________

20. We are going to draw a brace map table for the reactants and the products to prove the there has been a conservation of matter in this chemical reaction. Remember how fun brace maps are kids!?!

21. C + H 2 O CO + H 2 Pay special attention to the plus signs, and the arrow.

22. C + H 2 O CO + H 2

23. C HH O TOTAL = 4 C O HH TOTAL = 4

24. 2K + Br 2 2KBr KK Br TOTAL = 4 KK Br TOTAL = 4

25. CH 4 + 2O 2 CO 2 + 2H 2 O

26. AgNO 3 + LiOH AgOH + LiNO 3

27. 4Fe + 3O 2 2Fe 2 O 3

28. 2HCl + Zn H 2 + ZnCl 2

29. Chemical Reactions Song

30. Chemistry Humor Video

31. Bill Nye the Science Guy Chemical Reactions