2. Electrochemistry

4. A lemon can power a small light bulb. Where does the energy come from? RedOx reactions move electrons from one element to another. Moving electrons is electricity.

5. Electrochemistry Zn(s) + Cu 2+ (aq) → Zn 2+ (aq) + Cu(s)

6. 2e - Zn(s) + Cu 2+ (aq) → Zn 2+ (aq) + Cu(s) Zn → Zn 2+ + 2e - Cu 2+ + 2e - → + Cu Electrochemistry

7. Can we separate these half-reactions? Zn(s) + Cu 2+ (aq) → Zn 2+ (aq) + Cu(s) Zn → Zn 2+ + 2e - Cu 2+ + 2e - → + Cu

8. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu Electrochemistry

9. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu Electrochemistry

10. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu 1 st problem: No way to pass electrons from zinc to copper. Electrochemistry

11. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu 1 st problem: No way to pass electrons from zinc to copper. Solution: Add a wire. Electrochemistry

12. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu 1 st problem: No way to pass electrons from zinc to copper. Solution: Add a wire. Electrochemistry

13. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu 2 nd problem: Buildup of plus and minus charges. Electrochemistry

14. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu 2 nd problem: Buildup of plus and minus charges. Solution: A salt bridge. Electrochemistry

15. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu 2 nd problem: Buildup of plus and minus charges. Solution: A salt bridge. Electrochemistry

16. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu 2 nd problem: Buildup of plus and minus charges. Solution: A salt bridge. Electrochemistry

17. Zn → Zn 2+ + 2e - Cu 2+ + 2e - → Cu 2 nd problem: Buildup of plus and minus charges. Solution: A salt bridge. Electrochemistry

18. oxidation reduction A salt bridge is made of salt dissolved in gel. Ions can cross the bridge, but the solutions in the two beakers cannot. Electrochemistry

19. oxidation reduction This is a kind of electrochemical cell called a voltaic cell. Electrochemistry