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