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Electron Transfer in Chemical Reactions

Electron Transfer in Chemical Reactions. Redox Part II: Including batteries. Chapter 10. Redox Reactions in Our World. Batteries. Corrosion. Fuels. Manufacturing metals. Examples of Redox Reactions. Metal + halogen 2 Al + 3 Br 2  Al 2 Br 6. e . e .

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Electron Transfer in Chemical Reactions

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  1. Electron Transfer in Chemical Reactions Redox Part II: Including batteries Chapter 10

  2. Redox Reactions in Our World Batteries Corrosion Fuels Manufacturing metals

  3. Examples of Redox Reactions Metal + halogen 2 Al + 3 Br2 Al2Br6

  4. e e Electron Transfer in a Redox Reaction 2Ag+(aq) + 2Ag(s) + Cu(s)  Cu2+(aq) • Two electrons leave copper. • The silver ions accept them. • The copper metal is oxidized to copper (II) ion. • The silver ion is reduced to solid silver metal.

  5. 10.3 Recognizing Electron-Transfer Reactions (Continued) • Reduction • The gaining of electrons • Decrease in the overall oxidation state

  6. 10.3 Recognizing Electron-Transfer Reactions (Continued) • Oxidation • The loss of electrons • Increase in the overall oxidation state

  7. 10.3 Recognizing Electron-Transfer Reactions (Continued) • Oxidizing agent • Substance that oxidizes something else • Reducing agent • Substance that reduces something else

  8. 10.3 Recognizing Electron-Transfer Reactions (Continued) Which substance is the oxidizing agentand which is the reducing agent in the following: P4 + 6 Br2 4 PBr3

  9. 10.3 Recognizing Electron-Transfer Reactions (Continued) Which substance is the oxidizing agent and which is the reducing agentin the following: P4 + 6 Br2 4 PBr3

  10. 10.1 What Is Electricity? • Electricity is the flow of electrons. • Voltage is the push of the electrons.

  11. 10.1 What Is Electricity? (Continued) • Production of electricity • Occurs at power plants • Mechanically produced by generator • Wound copper wire spinning between magnets • Occurs in chemical reactions • Electrons released by atoms/compounds • Batteries are an example of a chemical-based release of electrons.

  12. 10.4 Electricity from Redox Reactions • Galvanic cell • Also known as a battery • Wire allows path for the flow of electrons

  13. 10.4 Electricity from Redox Reactions (Continued) • Salt bridge • Conductive component completing cell • Maintain charge balance between sides • Spectator ions • Ions not directly involved in the redox reaction • Electrodes • Metal strips submerged in the solutions

  14. 10.4 Electricity from Redox Reactions (Continued)

  15. 10.4 Electricity from Redox Reactions (Continued)

  16. 10.4 Electricity from Redox Reactions (Continued) • Standard cell battery • Redox reaction in a can • Reactants are MnO2 and Zn. • A semimoist paste containing NH4Cl acts as the salt bridge.

  17. 10.4 Electricity from Redox Reactions (Continued) Standard Cell Battery

  18. 10.4 Electricity from Redox Reactions (Continued) • A wire connecting terminals allows electron flow.

  19. 10.4 Electricity from Redox Reactions (Continued) • Cathode • Positive electrode • MnO2 in standard cell battery • Anode • Negative electrode • Zn in standard cell battery

  20. 10.4 Electricity from Redox Reactions (Continued) • Lithium ion battery • Made of Co+4 (cathode) • Li atoms in graphite sheets (anode) • Separator membrane

  21. 10.4 Electricity from Redox Reactions (Continued) • During discharge: • Li ions give up electrons. • Co+4 is reduced to Co+3. • LiCoO2 is formed.

  22. 10.4 Electricity from Redox Reactions (Continued) • Fuel cell • Battery in which one reactant is a combustible fuel and the other is oxygen.

  23. 10.5 Which Way Do Electrons Flow?—The EMF Series • Electron flow • Electrons flow from active metals to less active metals. • Electrons flow from Mg to Zn. • Electrons will not flow Zn to Mg. Electrons from Mg reduce the Zn cations. Mg dissolves as it becomes Mg+2 No reaction

  24. 10.5 Which Way Do Electrons Flow?—The EMF Series (Continued) Electromotive Force (EMF) Series

  25. 10.5 Which Way Do Electrons Flow?—The EMF Series (Continued) What will happen if a piece of Zn metal is placed in a solution of Al3+ ions?

  26. 10.5 Which Way Do Electrons Flow?—The EMF Series (Continued) What will happen if a piece of Zn metal is placed in a solution of Al3+ ions? Al is higher on the EMF series, so Zn will not spontaneously give up its electrons to Al3+.

  27. 10.6 Another Look at Oxidation: The Corrosion of Metals (Continued) • What is the Statue of Liberty made of? Fe frame inside for support with a copper metal sculpture outside

  28. 10.6 Another Look at Oxidation: The Corrosion of Metals (Continued) CuO is green • Oxidation on the Statue of Liberty • Copper slowly combines with oxygen in the air. • The formed Cu2+ could oxidize the Fe skeleton of the statue, endangering the structure.

  29. 10.6 Another Look at Oxidation: The Corrosion of Metals (Continued)

  30. 10.6 Another Look at Oxidation: The Corrosion of Metals (Continued) • Sacrificial metals • Metal piece designed to oxidize in place of another metal • Active metalschosen • Mg very common choice

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