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• Electrolysis is used to break down subsances .
• An ionic substance with freely moving ions is called a electrolyte
• Two electrodes are connected to a direct current electricity supply and placed into the electrolyte.
• The two types of ions carry opisite charges and so migrate towards the elctrode with the opposite current
• Cations are positive ions and are attracted to the negative cathode
• Anions are negative ions and are attracted to the positive anode
• At anode, negative ions lose electrons. At the cathode, electrons are transferred from the electrode to the positive ions

• You can predict the electrolysis products of any molten salt. The salt will always decompose into its element. The metal is produced at the cathode and the non metal is produced at the anode

Displacement reaction is a chemical reaction in which a more reactive element displaces a less reactive element from its compound. Both metals and non-metals take part in displacement reactions.

Very unreactive metals are found naturally in their native state

More reactive metals have reacted with other elements to form compunds in rocks 

The process of obtaining a metal from these compunds is extraction

An ore is a rock that contains enough of a compund to extract a metal for profit

Electrolysis is only used to ectract very reactive meatals that cannot be obtained by heating their oxides with carbon

Biological methods of metal extraction

Bioleaching is the process of using bacteria to dissolve metals instead of chemical solutions. Bioleaching has been used to dissolve metals such as nickel, copper, zinc, cobalt, gold, lead, arsenic and others. Bioleachingworks by using specific bacteria that can essentially “eat” the metal content out of ore.

Phytoextraction involves growing plants that absorb metal compounds, The plants are then burnt to form ash, from which the metal is extracted

Oxidation is the gain of oxygen by a substance

Reduction is the loss of oxygen from a substace.

They always occur together

a redox reaction is a reaction where oxidation and reduction occur

Corrosion

Corrosion happens when a metal rwacts with oxygen, making the metal weaker over time

The more reactive metal it is, the more rapidly it corrodes

Some metals such as aluminium does not corrode because their surfaces form a protective oxide layer, which prevents further reaction

Advantages of recycling

• Natural reserves of metal ores will last longer
• The need to mine is reduced
• Less pollution may be produced
• Many metals need less energy to recycle then extract it from a ore
• Less waste metal ends up in Landfill sites

Disadvantages of of recycling

• The costs and energy used in collecting
• Transporting and sorting metals to be recycled
• Sometimes it can be more expensive and require more energy then extracting a new metal

• Some reactions are able to go in two directions; forward and reverse. They are known as reversible reactions.
•  The forward and reverse reactions occur at the same time, and never stop. As a result, they are called dynamic reactions.
•  When the rate of the forward reaction is equal to the rate of the reverse reaction, the reaction is said to have reached equilibrium.
•  At equilibrium, the concentrations of the reactants and products are constant, but are not necessarily equal.

• a high temperature - about 450ºC-a high pressure - about 200 atmospheres (200 times normal pressure)-an iron catalyst