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What are batteries?

What are batteries?. How do they work?. Batteries. A battery converts chemical energy into electrical energy. Also called an electrochemical cell. The Activity Series of Metals A battery uses the energy created by the difference between the metals ability to lose their valence electrons.

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What are batteries?

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  1. What are batteries? How do they work?

  2. Batteries • A battery converts chemical energy into electrical energy. • Also called an electrochemical cell.

  3. The Activity Series of Metals A battery uses the energy created by the difference between the metals ability to lose their valence electrons. The metals at the top of the table will lose their valence electrons the easiest, thus are more active. Most active Least active

  4. Lead acid batteries

  5. Why are lithium batteries “better” than lead batteries? • Advantages: • Lithium is the most reactive metal (highest on the Activity Series) • Lithium is the lightest metal (lithium metal can even float on water) • Lithium has a smaller atomic radius than lead atoms (smaller in size) • Lithium batteries have a high charge density (more charge per mass) • Lithium is less toxic to the environment (and humans) than lead • Lithium batteries have a long life. • Disadvantages: • Lithium is a somewhat rare element (0.0007% of the earth's crust) • Lithium batteries are more expensive • Lithium is very reactive (so it can possibly catch fire or explode)

  6. The components of a simple battery • Two different metals serve as two ends (+ and – ends) • Salt bridge (electrolyte) connecting the two metals • A wire connecting the two metals (to conduct electricity)

  7. REDOX (Reduction/Oxidation)half-reactions • When the more reactive metal loses electrons it is OXIDIZED. This is called OXIDATION Zn is more active and loses electrons Zn  Zn +2 + 2 e –

  8. Oxidation/Reduction • The ions of the less reactive metal gains the electrons and is REDUCED. • This is called REDUCTION Cu is less active and gains electrons Cu+2 + 2 e - Cu

  9. REDOX (Reduction/Oxidation) • REDOX - When both reduction and oxidation half-reactions happen together to form a complete (single replacement) REDOX reaction. Reduction Cu+2 + 2 e - Cu Oxidation Zn  Zn+2 + 2 e – Total reaction Zn(s) + Cu+2(aq) Cu(s) + Zn+2(aq)

  10. Anode = Negative (Zinc loses electrons)Cathode = Positive (Copper gains electrons) Copper Top = copper is positive cathode

  11. REDOX REACTIONS • LEO the lion goes GER • Losing Electrons is Oxidation • Gaining Electrons is Reduction

  12. Batteries • Metals that are farther apart on the activity series will produce a battery that has a larger voltage.

  13. Batteries Li K Ca Na Mg AlZn Fe CdNi Sn Pb HCu Ag Au 0.51

  14. Review • Electrochemical cell = battery Chemical energy → electrical energy • Voltage – the difference in potential between the 2 metals • The greater the difference between the metals, the greater the voltage produced.

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