splits compounds (decomposes) into their
component elements using electricity
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what are electrolytes?
liquids with freely moving ions so they can produce electricity
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what are electrodes?
inert (unreactive) conductors that are charged
from an external circuit
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where do positive ions more to?
the negative cathode
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where do negative ions move to?
the positive anode
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what are positive and negative ions produced from?
positive- metal and hydrogen
Negative-non metals
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in molten compounds what is produced at the negative and positive electrode?
Anode- non metal
metal- cathode
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with metal when can electrolysis be used?
when the metal is more reactive than carbon
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what does cryolite do to molten aluminum?
Cryolite
lowers the melting
point and therefore
saves energy and
lowers costs
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what are the electrodes made of in the extraction of alumium?
what has to happen regularly?
made of graphite
The positive carbon(graphite) anodes must be continually
replaced because they wear away as they react with oxygen and
produce carbon dioxide gas which escapes
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what is produced at the cathode and anode in extraction of aluminum?
Molten aluminum metal
is produced at the negative
electrode
Oxygen gas is produced at the positive electrodes
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what are the equations for what happens at the cathode and anode?
Al + + 3e- → Al
2O → O + 4e-
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what does OILRIG stand for?
oxidation is loss, reduction is gain
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what are the reactions at the cathode?
At the cathode (-), positively charged ions gain electrons and so
the reactions are reductions. Reduction at the Cathode (-) Al + 3e- → Al
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what are the reactions at the anode?
At the anode (+), negatively charged ions lose electrons and so
the reactions are oxidations.
Oxidation at the Anode (+)
2O → O + 4e-
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what is produced at the Cathode in the electrolysis of and aqueous solution?
At the negative electrode (cathode), hydrogen
is produced if the metal is more reactive than
hydrogen if not then the metal is produced Cu, Ag, Au, Pt.
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what is produced at the anode in the electrolysis of and aqueous solution?
At the positive electrode (anode), oxygen is
produced unless the solution contains halide
ions, then the halogen is produced
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why does this happen?
This happens because in the aqueous solution
water molecules break down producing
hydrogen ions and hydroxide ions that are
discharged
H O → H + OH-
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what are the equations for the water in aqueous solutions?
REDUCTION 2H + 2e- → H
OXIDATION 4OH- → O + 2H O + 4e-
cathode; Hydrogen is less reactive than sodium, so H gas
Anode; Chlorine is a halogen so Cl gas is produced
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what is produced from the electrolysis of brine?
sodium hydroxide
Na+, OH-
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what is electroplating?
. Electroplating is coating a metal object with a
different metal.
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what happens in the electroplating of a spoon with silver?
The object has to become
the negative electrode to become plated (coated)
with metal from the positive electrode
Silver ions (Ag+) move to the negatively charged spoon and gain electrons
to become silver atoms
Ag+(aq)+ e- → Ag(s)
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what can electrolysis also be used for?
Electrolysis can be used to purify metals
• impure metal at the (+) electrode
• pure metal produced at the (-) electrode
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Other cards in this set
Card 2
Front
what are electrolytes?
Back
liquids with freely moving ions so they can produce electricity
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