Metals (C1.2)

Metals (C1.2)

1. Ores

   • Some metals are extremely unreactive so they are found naturally in the earth's crust. These are metals are gold, silver and platinum. They are found like his because they never react with other elements.
   • Most other metals are found in compounds. These are called ores (rocks from which metals can be extracted from for profit). All of these metals have to be extracted by heating them with carbon or by electrolysing them. Some of the ores are haematite (iron) and malachite (iron).
     • How reactive the metals are effects how they are extracted. If a metal is more reactive then carbon it has to be extracted using electrolysis, if not it is heated with carbon. Iron Oxide+Carbon=iron+carbon dioxide. In this experiment the iron has been displaced. An example of electrolysis is aluminium: aluminium oxide= aluminium+oxygen.

2. Oxidation & Reduction

   • Metal extraction is an reduction. This is because an extraction removes the oxygen from the compound. For example iron is obtained by removing oxygen from iron oxide.
   • When metals corrode they are going through oxidation. This is because they are reacting with the oxygen around them to form a metal oxide. When iron corrodes it is called rusting. Aluminium does not corrode because it has a thin layer of aluminium oxide around it, which protects it. The more reactive a metal, the more quickly it corrodes.

3. Recycling Metals

   • Many materials can be recycled. Metals can be recycled by melting them down and and making them into new things. There are many advantages and disadvantages of recycling metals.
     • Advantages: Reserves will last longer if we recycle; for most metals less energy is used to recycle them then to extract them; recycling stops mines ruining landscapes; recycling produces less pollution; more recycling means less landfill sites.
     • Disadvantages: the cost is much higher than it is to extract metals.
     • To start the process of recycling metals the metals need to be collected. Iron and steel are easily seperated from other metals because they are magnetic. Others are normally sorted by hand.

4. Properties of metals

   • Metals have many useful properties. Some of these include; they conduct heat and electricity; they are malleable (can be hammered into shape) and are ductile (can be stretched into different shapes). However the properties differ depending on the metal.
     • Aluminium- Aluminium has a very low density and it does not corrode. Aluminium is used mainly in making aeroplanes. This is beause the lighter the aeroplane, the less fuel it will need.
     • Copper- Copper is an extremely good electrical conductor and so it is used to make electrical cables. As well as this, copper does not react with water- making it ideal for use in water pipes. It replaced lead, as lead slowly reacted with water and gave people lead poisoning
     • Gold- Gold is very unreactive and does not corrode. It is also very attractive. It is mainly used to make jewellery as it can be easily moulded into beautiful shapes However it is also a very good electrical conductor and so is used on circuit boards in very small amounts.
     • Iron & Steel- Iron and steel are used more than any other metals. This is because iron s fairly cheap to extract and it is abundant. Pure iron id too soft to be useful so it is made into steel which is stronger and harder. Steel is a mixture of iron, carbon and other metals and it is used to make a massive range of things, including bridges, cars, electrical goods and many more. It is also magnetic which can be useful. However both iron and steel rust.

5. Alloys

   • Alloys are mixtures of many metals, so that a metals properties can be improve. Alloys are normally stronger than the original metal because the different atoms of other metals prevent the atoms from sliding over each other and slipping.
   • Some examples of allies are alloy steels which are all used fro many different things as well as different carat golds.

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