Topic 4

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Most metals are extracted from ores found in the Earth’s crust. Unreactive metals are found in the Earth as the uncombined elements

Most metals are either extracted from their ores by heating with carbon (cheaper) or the use of electrolysis (expensive).

EG iron oxide + carbon -> iron + carbon dioxide --- displacement reaction

EG aluminium oxide -> aluminium + oxide

The way a metal is extracted depends on it reactivity.

Oxidation is the gain of oxygen. Reduction the loss of oxygen. OIL RIG (electrons)

The extraction of a metal is a reduction process. Oxidation of metals leads to corrosion

A metal’s resistance to oxidation is related to its position in the reactivity series

Converting pure metals into alloys often increases the strength of the product

Iron is alloyed with othermetals to produce alloy steels with a higher strength and a

greater resistance to corrosion

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TOPIC 4 -cont

Alloying changes the properties of metals, including: smart or shape memory alloys, including nitinol, an alloy of nickel and titanium. Gold alloys with higher strength, including fineness (parts per thousands) and carats to indicate the proportion of pure gold

New materials are developed by chemists to fit new applications, such as the creation of new shape memory alloys for use, for example, in spectacle frames and as stents in damaged blood vessels

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