Test Objectives: Redox
 define oxidation
o know that oxidation is losing electrons
 define reduction
o know that reduction is gaining electrons
 know the memory aid OILRIG and how to use it
 assign oxidation numbers to each element in a compound or a polyatomic ion
o know the 8 rules for assigning oxidation numbers
 be able to identify if a reaction is a redox reaction
o be able to determine;
 what is being oxidized
 what is being reduced
 what is the oxidizing agent
 what is the reducing agent
 be able to correctly write & balance equations for the oxidation half reaction and
the reduction half reaction in a redox reaction
o know that electrical charge & mass must be conserved
o be able to recognize an improperly balanced half cell reaction
 be able to balance a redox equation by:
o balancing electrons lost and electrons gained
o balancing the atoms in the equation
 be able to identify single replacement reactions be able to use table J to predict
whether a given reaction will or will not occur
 know that there are two types of electrochemical cells: Voltaic (or Galvanic) and
electrolytic
o voltaic cells are batteries/electrolytic cells are plating cells
o know that NYS Regents only refers to voltaic cells as “electrochemical” cells
 know that voltaic cells are spontaneous and electrolytic cells are non-spontaneous
o voltaic cells are exothermic; electrolytic cells are endothermic
o voltaic cells produce electricity; electrolytic cells require an external source of
electricity to work
o be able to describe the differences between a voltaic cell & an electrolytic cell
 given two metals & using table J be able to draw and label all the components for a
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given voltaic cell including:
o both half cells
o salt bridge (including direction of positive ion flow)
o wire (including direction of electron flow)
o cathode, anode (including which electrode is positive & which electrode is
negative)
 know which electrode increases in mass & which electrode decreases in
mass
 know at which electrode oxidation occurs and at which electrode
reduction occurs (use table J )
know that in a voltaic cell as the redox reaction occurs:
o the cathode (+) loses mass while the cathode solution concentration increases
o the anode (-) gains mass while the anode solution concentration decreases
be able to explain the purpose of a salt bridge
know that in an electrolytic cell electricity is used to force a non-spontaneous
reaction to occur
o know that there are two types: fused salt cell & an electroplating cell
be able to draw and label all the components of an electrolytic cell:
o the anode (+) & the cathode (-)
o direction of electron flow
o chemical components
o be able to write the oxidation half reaction & the reduction half reaction
o know that reduction still occurs at the cathode & oxidation still occurs at the
anode
know that the “polarity” of the anode & cathode in an electrolytic cell is opposite that
of a voltaic cell
know these differences between voltaic & electrolytic cells
o voltaic:
 redox reaction is spontaneous & exothermic
 anode is negative , cathode is positive
o electrolytic:
 redox reaction is non-spontaneous & endothermic
 anode is positive, cathode is negative
know these similarities between voltaic & electrolytic cells
o both use redox reactions
o anode is site of oxidation
o cathode is site of reduction
o electrons flow through the wire from the anode to the cathode