Aka REDOX reactions Electrochemistry The study of chemical reactions involving the transfer of electrons between reactants Oxidation Loss of electrons happens at the anode Reduction gain of electrons ID: 625213
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Slide1
Oxidation & Reduction
Aka REDOX reactionsSlide2
Electrochemistry
The study of chemical reactions involving the transfer of electrons between reactants. Slide3
Oxidation
Loss of electrons
happens at the anodeSlide4
Reduction
gain of electrons
happens at the cathodeSlide5
Just remember
LEO the Lion says GER!Slide6
Oxidizing agent
A substance that gains electrons in a
redox
reactionSlide7
Reducing agent
A substance that loses electrons in a
redox
reactionSlide8
Half reaction
Either the oxidation or reduction reaction component of a redox reaction. Obtained by considering the change in oxidation states of individual substances involved Slide9
The history of redox
Metallurgy is the science of extracting metals from their naturally occurring compounds
Since most metals are found in ores (only gold and silver are found as naturally occurring elements) we need to get them alone through chemical processes
These processes are single replacement reactionsSlide10
REDOX reactions
REDOX reactions involve both oxidation and reduction reactions
The overall oxidation-reduction reaction involves the transfer of electronsSlide11
Half Reactions
Show the gain and loss of electrons
Net:
Cu(s
) + 2Ag+(aq)
Cu2+ + 2Ag(s)
Cu(s
)
Cu2+(aq) + 2e- (loss of
e
-)
2[Ag+(aq) +
e
-
Ag(s
)] (gain of
e
-)Slide12
How to:
Determine your overall reaction (just the reactants are required!)
Dissociate ionic compounds
Label whether each reactant is an oxidizing agent or a reducing agent (by looking at the chart)
Out of all the entities, determine your strongest agents (highest on the left, lowest on the right of the table)
Copy the half reaction
exactly
out of the booklet
Balance the electrons and cancel out the entities on both sides of the arrow to find the net equationSlide13
Example 1
Copper metal is placed in a solution of acidified potassium dichromate. Write a balanced
redox
reaction equation for the reaction of copper metal with postassium
dichromateSlide14
Example 2
Leaching technology is used in mining and refining of copper ore. In the first step of the leaching process, sulfuric acid flows through a copper ore deposit. Under ideal conditions, the copper metal in the ore reacts with the concentrated sulfuric acid to form
copper(II
) ions. The resulting
copper(II
) slurry is transferred to an electrolytic cell where pure copper is produced (assume that the sulfuric acid completely ionizes to hydrogen ions and sulfate ions).
A non-spontaneous reaction may occur if the concentrations are manipulated. Demonstrate the balanced net ionic equation for the reaction of copper metal with sulfuric acid under these ideal conditions. Slide15
Redox Reactions
If NO ELECTRON transfer occurs in a reaction, it is NOT a
redox
reaction
There must be a change in the oxidation numbers (one must decrease, one must increase)Slide16
Disproportionation
reactions
Disproportionation
reactions occur when the same entity is both oxidized and reduced in a
redox
reaction
AKA self-oxidation-reduction
AKA auto-oxidationSlide17
example
Cr(OH)
2
(
aq
) reacts with CrSO
4
(
aq
)