1. BASIC REDOX

2. In our Chemical Reactions Lab, we added COPPER METAL TO SILVER NITRATE SOLUTION - What happened?

3. The equation for this reaction is: Cu + 2AgNO3 → 2Ag + Cu(NO3)2 What type of reaction is this?

4. Lets look closer at what actually happened
Lets look closer at what actually happened. What are the charges on each of the substances below? (Reminder: Pure elements have no charge) Cu + 2AgNO3 → 2Ag + Cu(NO3)2

5. Remember that ionic compounds dissociate in water; so ionic compounds are actually separated in this reaction as follows:

6. So, if you cross out the substance that didn’t change, you find out the chemical changes that actually happened in this reaction. You can separate this complete reaction into 2 half-reactions.

7. In half-reactions: e- stands for
In half-reactions: e- stands for _______________ Each copper atom lost ___________ electrons. Each of the two silver ions gained ______ of those _______ electrons.

8. The number of electrons lost and gained in a reaction must be equal
The number of electrons lost and gained in a reaction must be equal. What Law demands this? You can use this fact to help balance difficult equations.

9. For example: the space shuttle is lifted off the earth by this tough redox reaction: NH4ClO4 + Al → Al2O3 + HCl + N2 + H2O

10. Label each of these substances

11. The copper atoms lost electrons; i. e
The copper atoms lost electrons; i.e., they were The silver atoms gained electrons; i.e., they were

12. Oxidation is the process in which a substance _______________electrons
Oxidation is the process in which a substance _______________electrons. Reduction is the process in which a substances __________________electrons. If you have one of these processes, you must have the other

13. How will you remember which is oxidation, and which is reduction.

14. An oxidation-reduction reaction (redox for short) is:

15. Some “real-life” examples of redox reactions…

16. Another example of a redox reaction…combustion!

17. This is a redox process by which your body stores energy
This is a redox process by which your body stores energy. You will talk about this in biology next year.

18. This type of reaction is ___________ a redox reaction
This type of reaction is ___________ a redox reaction. Single replacement Combustion Combination Decomposition reactions Double replacement

19. We will be doing a demonstration that includes redox reactions
We will be doing a demonstration that includes redox reactions. The demo is called the “Hindenburg.” What do you know about the Hindenburg?

20. In the early 1930’s, passenger air travel was through dirigibles (giant blimps). They were filled with hydrogen gas, because it is lighter than air. The Hindenburg (1936) was the “pride” of Nazi Germany – and capable of crossing the Atlantic Ocean.

21. What happened to the Hindenburg
What happened to the Hindenburg? There exists actual historic video footage of what happened to the Hindenburg – which we’ll see now!

23. In our demonstration, we will create a model of the Hindenburg
In our demonstration, we will create a model of the Hindenburg. First, we will do a redox reaction to generate hydrogen gas by adding aluminum foil to hydrochloric acid. We will use the hydrogen gas to fill a balloon, thus creating our own little “airship,” circa 1936.

24. What is the balanced equation for aluminum + hydrochloric acid?

25. Write the charges over each substance, and the half reactions
Write the charges over each substance, and the half reactions. What is being oxidized, and what is being reduced?

26. For each of the following reactions, write the half-reactions and determine which element has been oxidized, and which has been reduced. 1) 3Mg + 2Al(NO3)3 → 3Mg(NO3) Al 2) 2Li + CaCl2 → 2LiCl + Ca 3) 6K + 2H3PO4 → 2K3PO H2

27. 3Mg + 2Al(NO3)3 → 3Mg(NO3) Al

28. 2Li + CaCl2 → 2LiCl + Ca

29. 3. 6K + 2H3PO4 → 2K3PO H2

30. Final note: the reaction which destroyed the Hindenburg was also a redox reaction! 2H2 + O2 → 2H2O