C1.4 Obtaining and using metals Flashcards
Where are metals extracted from?
Ores in the Earth’s crust
How are most metals extracted from their ores?
- heating with carbon
- electrolysis
What are ores?
Rocks that contain enough of a metal for extraction to create profit
What is extraction?
The process of obtaining a metal from an ore by using chemical reactions
What happens to the cost of extraction as the reactivity of a metal increases?
It increases
Why does it cost more to extract metals with a high reactivity?
Electrolysis costs more than heating with carbon because of the cost of electricity
How are metals up to and including zinc on the reactivity series extracted?
By heating with carbon
How are metals above zinc on the reactivity series extracted?
By electrolysis
What is reduction in terms of electrons?
The gaining of electrons
Is the extraction of metal from their oxides reduction or oxidation?
Reduction
What is reduction in terms of oxygen?
The loss of oxygen
What is oxidation in terms of electrons?
The loss of electrons
What is oxidation in terms of oxygen?
The gaining of oxygen
What is rusting?
The corrosion of iron
What does the rusting of iron produce?
iron(III) oxide
What happens to the speed of corrosion as the reactivity of a metal increases?
It speeds up
Is the corrosion of a metal reduction or oxidation?
Oxidation
What are the advantages of recycling metal?
- natural reserves of metal ores will last longer
- it takes less energy to recycle instead of extract most metal ores
- less pollution
- less waste metals are disposed of in landfill sites
What are the disadvantages of mining?
It damages the landscape and creates dust and noise pollution
What are the disadvantages of recycling metal?
- the costs and energy used to collect, sort and transport metals
- recycling can sometimes be more expensive than mining for some metals
Why are recycled metals cheaper than mined ones?
It takes less energy to recycle a metal than to mine for it
How are iron and steel seperated from other metals in a recycling plant?
By using a magnet
How are metals that aren’t steel or iron sorted in a recycling plant?
By hand
What are the properties of aluminium?
- low density
- doesn’t corrode
What is aluminium used for?
To make aeroplanes and cars
What are the benefits of using aluminium for aeroplanes and cars?
It makes them lighter which means less fuel is needed
What are the properties of all metals?
- shiny when polished
- conduct heat and electricity
- malleable
- ductile
What are the properties of copper?
- extremely good conductor
- low reactivity
What is copper used for?
- making copper cables
- making water pipes
What are the properties of gold?
- very unreactive
- doesn’t corrode
- remains shiny
- one of the best electrical conductors
What are the uses of gold?
- jewellery
- in electronic devices
What are the properties of steel?
- strong
- magnetic
What are the uses of steel?
- electrical goods
- machinery
- cars
- frames for buildings
- bridges
What is an alloy?
A mixture of metals
Why is an alloy stronger than a pure metal?
It has atoms of different sizes so they can’t slide past each other as easily
Why is iron alloyed with other metals?
- to get stronger
- to sometimes resist corrosion
What is stainless steel made up of?
Iron and small amounts of chromium and nickel
What is the purity of gold measured in?
Carats or fineness
How many carats does pure gold have?
24
What is the fineness of pure gold?
1000 parts per 1000
What is nitinol?
An alloy of nickel and titanium
What is a shape memory alloy?
An alloy that returns to it’s original shape when heated
What are some uses of shape memory alloys?
- as stents in damaged blood vessels
- to make flexible spectacle frames
What is a smart material?
A material with a property that changes when there is a change in conditions
Why is gold alloyed with other metals?
To make it harder and stronger
