Extraction And Uses Of Metals Flashcards
Where are most metals found in the Earth?
Un reactive metals such as gold are found uncombined, however most metals do react with other elements to form compounds, which are found naturally in the Earths crust. If the compound contains enough of the pre to make it worth extracting then it is called an ore, which are finite resources.
How does extraction of a metal relate to its position on the reactivity series?
The more reactive a metal is, the harder it is to extract from a compound.
Metals less reactive than carbon can be extracted by reduction with carbon but metals more reactive than carbon have to be extracted by electrolysis.
How are metals extracted by reduction with carbon?
The ore is heated with carbon monoxide, e.g. iron oxide is reduced in a blast furnace to make iron. This is because more reactive elements form compounds more readily and since carbon is more reactive, it can displace the metal and oxidise.
How are metals extracted by electrolysis?
Very reactive metals form very stable ores so more reactive metals can’t be displaced by carbon and have to be extracted by electrolysis. Electrolysis uses electricity to separate the metal from other elements in the compound, e.g. aluminium is extracted from aluminium oxide using electrolysis
What are the common properties of copper, iron and aluminium?
- dense and lustrous (shiny)
- high mpts
- high tensile strength (strong and hard to break)
- malleable (can be hammered into shape)
- good conductors of heat and electricity
What are the uses of copper based on its properties?
Used in electrical components and wiring
- good conductor of heat and electricity, low resistance and efficient at transferring electricity
Used in heating systems (underfloor heating)
- allows quick transfer of heat to surroundings
What are the uses of iron based on its properties?
Wrought iron is used to make gates and railings
- malleable
However it corrodes/rusts very easily
What are the uses of aluminium based on its properties?
Used for drinks cans
- doesn’t corrode easily because of protective layer of aluminium oxide that forms due to contact with air, which stops any further reactions from taking place
Used in aeroplane bodies
- less dense than iron - lighter
What are the uses of steel based on its properties?
Low carbon steel is used for car bodies because it is easily shaped
High carbon steel is used for bridges because ir is very strong, inflexible and brittle
Stainless steel is used for cutlery and pans because it is corrosion resistant and hard
What is an alloy?
A mixture of a metal and one or more elements, usually other metals or carbon
Why are alloys harder than pure metals?
Regular structure of pure metals makes them soft, but different elements have different sized atoms. So when other elements are mixed with a pure metal, the new atoms will distort the regular layers of metal atoms, making it more difficult for them to slide over each other, making alloys harder than pure metals.
