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Chemistry 1- Extracting metals and making alloys (Ores-naturally occurring…
Chemistry 1- Extracting metals and making alloys
Ores-naturally occurring rocks that contain metal or metal compounds in sufficient amounts to make it worthwhile extracting (economic)
Most everyday metals are mixtures called alloys
Earths crust contains metals and metal compounds such as gold, iron oxide and aluminium oxide- often mixed with other substances in ground
Metals need to be extracted
Ores are mined- need to be concentrated before metal is extracted and purified
Economics of ores may change over time
As a metal becomes rarer an ore may be used when it was considered to expensive to mine before
Metals produced when metal oxides reduced (have oxygen removed)
Reduction depends on reactivity of metal
Aluminium and other reactive metals reduced by electrolysis
Iron and other unreactive metals can be reduced by reducing with carbon or carbon monoxide
potassium, sodium, calcium, magnesium, aluminium can be extracted by electrolysis
Zinc, iron, tin and led can be extracted by carbon and carbon monoxide
Copper, silver, gold and platinum can be extracted in various ways
Due to golds reactivity (Unreactive) it is found as the native metal and not the compound, does not need to be chemically extracted from ore chemical reactions may need to remove other elements which may contaminate it
Transition metals are good conductors and can be hammered or bent into shape easily useful as construction materials and useful for making objects which need to transfer heat and electricity
Iron- extracted from iron ore (such as haematite) in blast furnaces, oxygen must be removed from iron oxide to leave iron behind
Reactions in which oxygen removed are called reduction reactions
Carbon more reactive than iron so it displaces iron from iron oxide and carbon makes carbon dioxide
Iron oxide+carbon> Iron+carbon dioxide
2Fe2O3 + 3C → 4Fe + 3CO2
In blast furnace its so hot carbon monoxide reduces to iron oxide
Copper- soft and easily bent, good conductor of electricity, useful for wiring, good conductor of heat, does not react with water, useful for plumbing making pipes and tanks
Some copper ores- copper rich- high concentration of copper compounds
Copper can be extracted from ores by heating them in a furnace- smelting, then purified using electrolysis
Electricity passed through solutions containing copper compound such as copper sulphate, positive charged ions move towards negative electrode deposited as copper metal
Running out of copper rich ores
Research to find new ways to extract copper from low grade ores without harming environment too much
Phytomining- extracting copper from plants which absorbed copper through roots and concentrated, burned to ash with copper compounds in
Bioleaching-some bacteria absorb copper compounds they produce solutions called leachates which contain copper compounds, copper extracted from this
Copper can also be extracted from solutions of copper salts such as scrap iron, iron more reactive than copper so displaces copper from its salt
Iron+copper sulphate>Iron sulphate+Copper