Electrolysis

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  • Created by: sara.5
  • Created on: 19-04-18 20:27
What is meant by Electrolysis?
The process by which ionic substances are decomposed into simpler substances when an electric current passes through them
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What is meant by Electrolyte?
An ionic substance with freely moving ions and can conduct electricity
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What is the process?
Two electrodes are placed in an electrolyte. When a power supply connected to the electrodes one terminal become negative(CATHODE) and the other positive(ANODE).The ions in the electrolyte are attracted to the opposite charge and split apart
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What are Cation attracted to?
Cations are positive ions and are attracted to the negative Cathode
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What are Anions attracted to?
Anions are negative therefore are attracted to the positive ion
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What is an electrode?
A rod made of metal or graphite that carries the current into or out of the electrolyte
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Why does the electrolytes need to be moltened?
So that the ions are free to move
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What do electrodes tend to be made out of?
inert or unreactive substance that have high melting point such as platinum of Graphite (a form of Carbon)
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What happens at the Cathode?
Electron are gained Cu+ +2e--->Cu REDUCTION happens
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What happens at the anode?
Electrons are lost 2Cl-->Cl2 + e- OXIDATION occurs
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Which metal is discharged at the Cathode?
-If metal are part of the transition metal it is discharged -If part of Group 1/2 then Hydrogen is discharged
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Which metal is discharged at the Cathode?
If halide ions then that is discharged-Other than that OH is discharged
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What is the Ionic equation for OH?
4OH- -->O2+2H2O + 4e
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How does metal react with cold water?
It produces Hydrogen and Metal Hydroxide
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How does metal react with Steam?
Forms a hydrogen and solid metal rock
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How does metal react with dilute acid?
Hydrogen and a salt solution.Bubbles of gas will be seen.The more bubble the more reactive the metal
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What happens in all of the above reaction?
The metal atoms lose electron to form positive ions(cation)
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How do you know how high the metal is in a reactivity series?
How easily a metals atoms lose electron
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What is meant by an ore?
An ore is a rock that contains enough of a compound to extract a metal profit
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What is the aluminium name of ore?
Bauxite COMPOUND Aluminium Oxide
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What is the copper name of ore?
Malachite COMPOUND Copper Carbonate
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What is the copper name of ore?
Haemitite COMPOUND Iron Oxide
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What elements are used to heat with Carbon?
Carbon can be used to extract some metals their ores.Copperoxide+Carbon-->Copper + Carbon Dioxide The copper oxide has lost energy this is called a reduction reaction
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What are the two methods of biological metal extraction?
Bioleaching and Phytoetraction
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Why do we need to use biological l methods of metal extractions?
-Copper ores are running out and so we need to extract copper from ore containing much smaller amounts of copper compounds
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What does Bioleaching involve?
-uses bacteria grown on low grade ore.-The bacteria produce a solution containing copper ions, called Lechate.Copper is extracted from the lechate by displacement reaction using scrap iron then purified by electrolysis.-Can be used for other metals
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What does Phytoetraction include?
Involves growing plats that absorb metal compounds. The plant is burnt to form ash from which metal is extracted.
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What are the advantages of both processes?
-No harmful gases released causes less damage to landscape than mining-Conserves supplies for higher grade ores
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What are the disadvantages of both processes?
Very slow
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What are the advantages of Bioleaching only?
Does not require high temp
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What is the disadvantage of Bioleaching alone?
Toxic substance and sulfuric acid can be produced by the process and damage environment
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What is the advantage of phytoextraction only?
Can extract metals from contaminated soils
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What is the disadvantage of phytoextraction only?
-More expensive than mining some ores growing plants in dependent weather conditions
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What happens when metal are recycled?
It is melted and made into something new
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What are the advantage of recycling?
-Natural reserves of ores will last longer-Need of mine ores reduced .Minning damage landscapes/create noise/dust pollution-Less pollution eg Sulfur dioxide is formed when some metal are extracted from metal sulfide ions
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Other ads?
Many metals nees less energy to recycle than to extract new from ore-Lest waste metal on ladfill sites
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What re the disadvantage?
Cost too high
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Why is a life cycle assessment cycle carried out?
To work out the environmental impact of a product and helps to decide whether it is worthwhile to manufacture/recycle a product
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Other cards in this set

Card 2

Front

What is meant by Electrolyte?

Back

An ionic substance with freely moving ions and can conduct electricity

Card 3

Front

What is the process?

Back

Preview of the front of card 3

Card 4

Front

What are Cation attracted to?

Back

Preview of the front of card 4

Card 5

Front

What are Anions attracted to?

Back

Preview of the front of card 5
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