Karteikarten
C1.3
Karten in diesem Stapel (25)
- 1What is an ore?It is a rock which contains enough metal to make it worthwhile extracting the metal from it.
- 2How do we get ores? What will be their state before the metal is extracted?They are mined.
They may be concentrated - 3What normally happens with most other metals when mined?Most metals are found as compounds that require chemical reactions to extract the metal.
- 4Why is gold found in the earth by itself?It is unreactive
- 5How are metals less reactive than carbon extracted from their oxides?By reduction with carbon.
- 6How are metals that are more reactive than carbon extracted from their oxides?Using electrolysis
- 7What make metals more reactive than carbon expensive?Electrolysis requires a large amount of energy which is expensive
- 8How can copper be extracted from copper-rich ores?By heating the ores in a furnace (smelting). It is then purified by electrolysis.
- 9What are a few problems with mining copper?Copper-rich ores are limited and traditional mining and extraction have major environmental issues.
- 10Why are new ways being researched to mine copper?To limit the environmental impact and to obtain more copper from low-grade ores.
- 11What are the two new ways of extracting copper?Phytomining and bioleaching
- 12Explain phytominingIt uses plants to absorb metal which are then burnt to leave ash with the metal compounds.
- 13Explain bioleachingIt uses bacteria to produce leachate solutions that contain metal compounds
- 14What are two ways that copper can be obtained from copper salts?By electrolysis or displacement using scrap iron
- 15Why is it more expensive to extract titanium and aluminium from their oxide?Because they cant be extracted from their oxides by reduction with carbon. The methods of extraction used have many stages and large amounts of energy is needed.
- 16Why should we recycle metals?Extracting them uses limited resources and is expensive in terms of energy and effects on the environment.
- 17Why does iron have limited uses?Iron from the blast furnace is only 96% iron. The impurities in it make it brittle
- 18Why is iron from the blast furnace used as cast iron?Because of its strength in compression
- 19What is most iron converted into? What are these?Steels are alloys as they are a mixture of iron and carbon. Some steels contain other metals
- 20What is the difference between low-carbon steels and high-carbon steels? What are stainless steels?Low-carbon steels are easily shaped and high-carbon steels are hard. They are resistant to corrosion
- 21Why are most metals in everyday use alloys?Because pure copper, aluminium, gold and iron are too soft for many uses, so they are mixed with small amounts of similar metals to make them harder for everyday use
- 22What are the elements in the centre of the periodic table called? What are their characteristics?Transition metals.
Like other metals they are good conductors of heat and electricity and can be bent or hammered into shape. - 23What are transition metals useful for?As structural materials and for making things that must allow heat or electricity to pass through them easily.
- 24What copper used for and why?It is used for electrical wiring and plumbing because it is a good conductor of heat and electricity and it does not react with water. Also it can be bent but it is hard enough to be used to make pipes or tanks.
- 25What properties make aluminium and titanium useful metals?They have a low density and are resistant to corrosion
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- Karteikarten am C1.3, erstellt von happyhats am 23/04/2014.
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- happyhats
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