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Batteries and Fuel Cells

Pgs 655 - 658. Batteries and Fuel Cells. How can we use galvanic cells in everyday life?. BATTERIES!! Take galvanic cells and make them easier to carry around and use! . All batteries require electrical potential:. Li Rb K Cs Ba Sr Ca Na Mg Al Zn Cr Fe Ni Sn Pb Cu Hg Ag Au.

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Batteries and Fuel Cells

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  1. Pgs 655 - 658 Batteries and Fuel Cells

  2. How can we use galvanic cells in everyday life? • BATTERIES!! • Take galvanic cells and make them easier to carry around and use!

  3. All batteries require electrical potential: Li Rb K CsBa Sr Ca Na Mg Al Zn Cr Fe Ni Sn Pb Cu Hg Ag Au Most reactive • What is electrical potential: • The “pressure” on electrons to flow from one electrode to the other in a redox reaction • Depends on the difference between the atoms being oxidized and reduced on the activity series • Measured in volts Least reactive

  4. Types of Batteries Lead Storage Batteries Dry Cell Batteries

  5. Dry Cell Batteries • Advantage of this type of battery: • Small, efficient at producing energy, don’t contain a liquid • Anode = Zinc case • Solid Zn is oxidized at anode: • Zn (s)  Zn2+ + 2e- • Cathode = Graphite rod • NH4+ and MnO2 is reduced • Used in calculators, watches, flashlights • What makes an alkaline battery different? • Last longer because the Zn doesn’t corrode as quickly in the basic environment!

  6. How does our lab from Friday link to corrosion? • Corrosion is the process of returning metals to their natural state • It’s a REDOX reaction!! Fe (s) + O2 (g)  Fe2O3 (s)

  7. LOTS of metals corrode, but not all of them corrode to the same extent: • Ex  Aluminum!! • Aluminum will be oxidized by the air • Al (s) + O2 (g)  Al2O3 (s) • A thin layer of Al2O3 will cover the metal and protect it from further corrosion

  8. How can we protect these metals from corrosion? • The Mg will react instead of the iron…but why???

  9. Lead Storage Batteries • Advantages of this type of battery: • Can work for several years in extreme temperatures • Provides a lot of voltage (12 V) for its size • RECHARGE themselves!! • Where do we use lead storage batteries? • IN CARS!!!

  10. Lead Storage Batteries • Anode = metal lead • Cathode = lead (IV) oxide coated onto lead grids • Solution = H2SO4 • Anode and cathode are separated, so the e- move through a wire that provides an electric current to run the car

  11. So what about hydrogen fuel cells? • Fuel cells: galvanic cells in which a fuel substance undergoes oxidation which creates energy • Don’t have to be re-charged • Can be created so that no air pollutants are produced • Used to run the Apollo missions • Trying to find a way to use them in cars!

  12. Hydrogen Fuel Cells • Cathode compartment has oxygen gas • Anode compartment has hydrogen gas • Middle compartment a membrane that allows H+ to move to O2 • Oxidation: 2H2 (g)+  4H+ + 4e- • Reduction: O2 (g) + 4H+ +4e-  2H2O (l) • Overall: 2H2 (g) + O2 (g)  2H2O (l)

  13. Hydrogen Fuel Cells and Cars http://www.chevrolet.com/fuelcell/ Show fuel cell Nova science now video

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