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2012-12-03 17:13:41

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  1. metals
    • can be extracted from rocks and minerals
    • few metals (gold and silver) exist naturally 
    • most metals exist as compounds called ores
  2. reduction of metals 
    producing metals from their compounds ex red iron oxide is reduced by CO extract
  3. reducing agent
    causes the reduction of a metals compound to an elemental metal 
  4. most common reducing agents
    CO C and H
  5. oxidization 
    reactions of substances with oxygen explosive, corrosion, burning
  6. oxidizing agent
    a substance that causes the oxidation of a metal compound
  7. half reaction 
    represents what is happening to only one reactant in a n overall reaction -- makes explanations simple
  8. half reaction conttt
    atoms are voncerted to ions and ions are converted into atoms
  9. reduction 
    the gain of electrons 
  10. oxidation
    the loss of electrons
  11. the total number of electrons gained must
    be equal to the total number of electrons lost 
  12. reduction and oxidation 
    are seperate processes
  13. redox reeactions
    chem reaction in which leectrons are transferred between particles
  14. oxidation state
    apparent net electric charge that an atom would habe if electron pairs in vocalent bonds belonged entirely to the more electreonegative atom 
  15. metals and monatocmic anions 
    lose electrons oxidized 
  16. nonmetals and monatomic cations 
    gain electrons reduced
  17. oxidation number 
    positive of negative number corresponding to the oxidation state assigned to an atom
  18. more elecroneg
  19. less electroneg
  20. oxidation 
    increase in ioxidation number
  21. reduction 
    decrease in oxidation number 
  22. redox reaction 
    transfer of valence electrons from one substance to another
  23. competition for electrons
    • each particle pulls on the same electrons
    • if one particle is able to pull electrons away from the other a pontaneous reaction occurs
  24. reducing agent
    a susbtance that loses electrons to another 
  25. oxidizind agent
    a substance that gains or removes electrons from another susbstance
  26. the spontanity rule 
    a spontaneous redox reaction occurs only if the oxidizing agent (OA) is aboce the reducing agent (RA) in a table of relative strenghts of oxidizing and reducing agents
  27. OA 
  28. RA
  29. electric cell
    a device that continusously converts chemical energy into electrical energy
  30. battery 
     a group of two or more electric cells connecte in series
  31. electrode
    a solid electrical conductor there are 2in each cell
  32. electrolyte 
    an aqueous electrical conductor one in each cell in b/w the two electrodes
  33. cathode
    positive electrode
  34. anode
    negative electrode
  35. voltmeter
    device used to measure the energy difference per unit electric charge between two points in an electric circuit
  36. electric potential difference (voltage)
    the potential energy difference per unit charge
  37. volt (V)
    • the SI unit for electric potential difference 
    • 1v =1 j/c
  38. voltage depends on
    the chemical composition of the reactants in the cell not size
  39. electric current
    the rate of flow of charge past a point 
  40. larger electric cell =
    greater current
  41. ampere (A)
    the SI unit for electric current (I)
  42. cou.omb (C)
    the SI unit for electric charge and expresses the total charge tranferred by the movement of charged partivles charge (q)
  43. power (P) of a cell or battery 
    • the reate at which it produces electrical energy 
    • measure in watts (W)
    • calculated as the product of current and voltate
  44. energy density or specific energy
    • measure of energy stored or supplied 
    • meaused in j/kg
  45. half cell
    and electrode and an electrolyte forming half of a complete cell
  46. galvanic cell
    arrangement of two half cells that can produce electricity spontaneously
  47. cathode 
    the electrode where reduction occurs
  48. anode
    the electrode where oxidation occurs
  49. the strongest oxidizing agent present in the cell always
    undergoes a reduction at the cathode
  50. the strongest reducing agent present in the cell always 
    undergoes an oxidation at the anode
  51. the direction of electron flow can be expalined in terms of competition of 
  52. electrons flow
    from anode to cathode EXTERNALLY
  53. electron flowwww
    • cathode(+)l electorlyte ll electrolyte l anode (-)
    •        reduction                          oxidation

    •                             anions-->
    •                             <--cations
  54. inert electrode 
    •  a solid conductor that will not react with any substances present in a cell 
    • usually platinum or carbon
  55. galvanic cells consist of 
    2 half shells seperated by a prous boundry with solid electrodes connected by an exernal circuit
  56. internally anions move toward
    the anode
  57. internally cations move toward
    the cathode 
  58. standard cell
    a galvanic cell in which each half cell contains all entities shown in the half reaction equation at SATP conditions with the concentration of 1.o mol/L for the aq entities
  59. standard cel potential (delta E0)
    the max electric potential difference (voltage) of a cell operating under standard conditions
  60. standard reduction potential 
    the ability of a standard half cell to attract electrons in a reduction half reaction
  61. reference half cell 
    a half cell abritarily assigned an electode potential of exactly zero volts the standard hydrogen half cell 
  62. standard cell potential equation
    • E   =    Er     -   Er
    • cell   cathode    anode
  63. solution of salt bridge
    The solution in a salt bridge must be a “spectator” electrolyte chemically; that is, its ions must not react with the halfcell ions that pass through.