C1.3 Metals and Their Uses Flashcards
What is a metal ore?
A rock which contains enough metal to make it profitable to extract the metal from it
How are metals removed from the rock? (3)
Through chemical reactions: electrolysis, reduction or displacement
What makes a metal ore economically profitable?
If it sells for more money than what was invested to extract it
What does the position of a metal in the reactivity series determine?
How it is extracted from it’s ore
Metals below carbon in the reactivity, how are they extracted from their ores?
They are extracted from their oxides using reduction
Metals above carbon in the reactivity, how are they extracted from their ores?
They at extracted from their oxides using electrolysis (which is expensive)
How does extraction by reduction with carbon work?
Oxygen is removed from the metal ore leaving a pure metal
Can you give the word equation for the reduction of Iron(III) oxide?
Iron(III) oxide + Carbon ==> Iron + Carbon Dioxide
Why is electrolysis so expensive?
It uses a lot of energy
What is copper extraction using carbon?
Copper can be extracted by reduction with carbon - the ore is heated in a furnace (smelting). But, the copper is impure so electrolysis is used to purify it (this can only occur with copper-rich ores)
What is electrolysis?
The breakdown of a substance using electricity
What is the liquid in electrolysis called?
The electrolyte, this is used to conduct the electricity. Electrolytes are often metal salt solutions made from the ore or molten metal oxides - the electrolyte has free ions which allows it to conduct the electricity
Electrolysis requires two…
Electrodes, one positive, one negative - electrons are gained or lost at electrons
How is copper extracted from copper-rich ores?
By reduction with carbon, or electrolysis
What happens at the positive/negative electrode in the electrolysis of copper?
At the positive electrode ions are formed, and atoms bond to the negative electrode
What are the steps in the electrolysis of copper? (3)
- Electrons are pulled off copper atoms at the + electrode, causing them to go into the solution as Cu2+ ions
- The Cu2+ ions move towards the - electrode, gain electrons are turn into copper atoms
- The impurities are dropped at the + electrode as a sludge, whilst pure copper atoms bond to the - electrode
What are the electrodes made of in the electrolysis of copper?
The - electrode is made of: a thin piece of pure copper
The + electrode is made of: A big lump of impure copper
How and why is copper extracted from low-grade copper ores?
Because copper-rich ores if limited and the demand for copper is high, so low-grade ores are extracted using bioleaching and phytomining
How does bioleaching work when extracting copper from low-grade ores?
Bacteria separates copper from copper sulphide. The bacteria gets energy from the bond between the copper and sulphur, which separates the copper from its ore. From this, a leachate is formed which contains copper which can be extracted
How does phytomining work when extracting copper from low-grade ores?
Growing plants on soils that contains copper - the copper builds up in the plants leaves, which can be harvested, dried and burned in a furnace. The copper is collected in from the ash in the furnace
What are the benefits of phytomining and bioleaching? (2)
They need less energy, which is Cheaper, produces less damage to the environment and Pmining is carbon neutral
What is the main drawback of phytomining and bioleaching?
They are very slow e.g. in Pmining, it’s long for the plants to grow
How does a displacement reaction happen?
A more reactive metal replaces a less reactive metal in a compound - this is because the more reactive metal bonds more strongly to the non-metal of the compound and pushes out the less reactive metal
How is copper extracted using displacement?
Scrap iron is put in a solution of copper sulphate solution and the more reactive iron kicks out the copper producing pure copper and ion sulphate (Copper sulphate + Iron ==> Iron Sulphate + Copper)
What are the positive impacts of metal extraction? (3)
Mining ores means useful products can be made, provides jobs and brings money into the local area, which means transport and health can be improved
What are the negative impacts of metal extraction? (7)
Noise pollution, traffic inc. because of the lorries going into and leaving the mine, destroys habitats, scars the landscape, leaves deep mine shafts which are abandoned (dangerous), solid waste like big rocks are left behind which can be an eyesore and mining needs a lot of energy which comes from F’fuels which causes…
Why is it important to recycle metals? (4)
Uses less energy than having to mine for new metal - this also saves money, there’s a finite amount of each metal so it conserves metals and it also reduces the amount of rubbish in landfills
What are the properties of metals? (4)
They are strong, can be bent into shapes, good conductors of heat and electricity
What makes metals good for everyday uses?
They’re strength and bendability makes them good for bridges and car bodies, their heat conductivity makes them good for saucepans and their electrical conductivity makes them good for wires
What are the properties of copper? (4)
Good conductor of electricity, hard and strong but can be bent and it doesn’t react with water
What are the properties of aluminium? (4)
It’s corrosion-resistant, it has a low density so it’s lightweight, it’s not very strong but it forms strong alloys
What are the properties of titanium? (4)
Has a low density so it is lightweight, it’s very strong and it’s corrosion-resistant
What can copper be used for? (2)
It doesn’t react with water and can be bent into shapes so it’s good for plumbing, and it’s a good conductor of E’ so it’s used in wires
What can aluminium be used for?
It can make strong, light alloys which can be bent into shape, so it is ideal for aeroplanes
What can titanium be used for?
It doesn’t corrode when in contact with water, lightweight and not too bendy so it is used for replacement hips
How can metals be protected from corroding with air and water?
By coating them in paint
What happens when a metal corrodes?
They lose their strength and hardness
What is metal fatigue?
When stresses and strains are put on them over time, the metals can break
What is an alloy?
A mixture of two or metals, or a mixture of a metal and a non-metal
What can impure iron do? (2)
It can be poured into shapes and withstand being compressed
Why is iron purified?
Iron straight from the blast furnace is about 96% iron and 4% impurities like carbon - these impurities make the iron brittle
How is iron purified?
The impurities are removed from the blast furnace iron to make pure iron
What is cast iron (impure iron) used for?
Ornamental railings
What is the structure/properties of iron? (3)
It has a regular arrangement of layered atoms that can slide over each other making the iron soft and easily shaped, this iron is too bendy so it is used in alloys
How is pure iron turned into steels?
By adding small amounts of carbon and sometimes other metals
What is low-carbon steel used for? What is it’s properties?
It’s used for car bodies as it is easily shaped
What is high-carbon steel used for? (2) What is it’s properties? (2)
It’s used for blades in cutting tools, and bridges, this because it’s very hard and inflexible
What is stainless steel used for? (2) What is it’s properties? (1) How is it made?
Chromium is added and sometimes nickel. It is corrosion-resistant so is used for cutlery and containers for corrosive substances
Why are alloys used?
They are harder than pure metals
Why are alloys harder than pure metals?
Because they have different sized atoms which disrupts the regular arrangement making it hard for the layers to slide over each other
What is bronze made of? (2) What’s it’s properties? What’s it used for? (2)
Made from copper and tin. It’s harder than copper so it’s used in making metals and statues
What is cupronickel made of? (2) What’s it’s properties? (2) What’s it used for?
Made from copper and nickel. It’s hard and corrosion-resistant, so it’s used in making ‘silver’ coins
What are gold alloys made of? (5) What are they used for?
Metals like zinc, copper, silver, palladium and nickel are used to strength soft pure gold, it is used in jewellery
What’s are aluminium alloys properties? What are they used for?
Aluminium has a low density and is alloyed with other metals to strengthen it. It is used in aircrafts
