Electrolysis

Electrode:

1. An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte or a vacuum)
2. Electrolysis can only work in molten or liquid compounds because current cannot pass through solid ionic compounds.

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• A negative electrode is called a 'Cathode'.
• A positive electrode is called an 'Anode'.

One way which you can remeber which electrode is which, think P.A.N.I.C! It stands for "Positive Anode, Negative Is Cathode"

• Positive ions are attracted to the Cathode, these are called cations.
• Negative ions are attarcted to the Anode, these are called anions.

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Electroplating:

...is coat (a metal object) by electrolytic deposition with chromium, silver, or another metal.

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• The negative electrode is made of the object to be electroplated.
• The positive electrode is made of the matal to coat the object with.
• The electrolyte is the solution of the coating metal.

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Redox Reactions:

An oxidation-reduction (redox) reaction is a type of chemical reactionthat involves a transfer of electrons between two species. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron.

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• When an ion loses electrons, it is oxidised
• When an ion gains electrons it is reduced

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Brine:

Sodium Hydroxide chlorine and hydrogen gas are products of this.

• Chlorine is used to kill bacteria in pools.
• The sodium hydroxide is used to bleach for cleaning.
• Hydrogen is used as fuel.
• Brine is concentrated sodium choloride solution.
• The chloride ions move to the anode and chlorine gas is produced.
• The sodium is more reactive than the hydrogen.
• The sodium stays in the electrolyte and becomes sodium hydroxide.
• The positive hydrogen ions moveto the cathode.

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Lead Bromine:

• Lead bromide solution is the electrolyte.
• The lead ions are attracted to the cathode.
• The bromide ions are attracted to the anode.
• ===> Bromide Gas is given off!

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Extraction of Aluminum:

• Aluminium ore is known as Bauxite. We extract Aluminium from Bauxite and purify it.
• Aluminium oxide's boiling point is too high so we dissolve it in molten cryolite to lower it. Chaper

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Electrolysis of Aluminium Oxide:

• Aluminium forms at the cathode and is tapped off.
• The electrodes are made out of graphite, The anodes need replacing often.
• The oxygen produced becomes carbon dioxide and burns away the anodes.

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