Topic 4 Flashcards
What is a metal ore?
Most metals react with other elements to form compounds, which can be found naturally in the earths crust. if a compound contains enough of the metal to make it worthwhile extracting, the compound is called a metal ore.
Explain the difference between oxidation and reduction.
Lots of common metals, like iron and aluminium, react with oxygen to form oxides. this process is called oxidation. These oxides are often the ores that the metals need to be extracted from. a reaction that separates a metal from its oxide is called a reduction reaction.
Name two ways in which metals are often extracted from their ores.
Electrolysis and heating with carbon.
What is bauxite?
Bauxite is an amorphous clayey rock that is the chief commercial ore of aluminium. It consists largely of hydrated alumina with variable proportions of iron oxides.
Metals are used for car bodies, saucepan bases and electrical wires. For which of these uses, give one reason why metals are appropriate.
All metals have some typical properties:
Metals are strong (hard to break), but they can be bent or hammered into different shapes.
They are great at conducting heat.
They conduct electricity well.
Metals have loads of everyday uses because of these properties.
Why are metals high in the re-activity series most likely to corrode?
Metals which are high in the re-activity series are more likely to corrode because they react more easily with oxygen. for example is less corrosion resistant than lead.
What is the problem with using iron straight from the blast furnace?
Iron extracted in a blast furnace using carbon monoxide is only 96% iron. The other 4% is impurities including carbon.
What is the problem with using very pure iron?
Pure iron is too bendy to use so it doesn’t have a lot of uses.
Why are alloys harder than pure metals?
Different elements have different sized atoms. so when an element such as carbon is added to pure iron, the smaller carbon atom will upset the layers of pure iron atoms, making it more difficult for them to slide over each other. so alloys are harder.
Give two examples of alloys and state what is in them.
Amalgam-The main metal is Mercury.
Brass-The main metals are Copper and Zinc.
Solder-The main metals are Lead and Tin.
What is so clever about smart alloys?
Smart alloys have a shape memory property, they “remember” their original shape. if you bend a wire made out of a smart alloy it will go back to its original shape when heated. Smart alloys are often used in glasses frames in case they get bent or sat on they can be heated back into their original shape.
Give three reasons why it is good to recycle metal?
It uses less resources-there is a finite amount of metals in the Earth. Recycling conserves these resources.
It uses less energy-mining and extracting metals needs a lot of energy, which mostly comes from burning fossil fuels,which causes pollution and will eventually run out. Recycling things like copper and aluminium takes a fraction of energy.
It uses less money-Energy doesn’t come cheap, so recycling saves money too.
It makes less rubbish-recycling also cuts down on the amount of rubbish that goes to landfill, which takes up space and pollutes the surroundings.
