CC11 Extracting Metals Flashcards
For the extraction of which metals is electrolysis needed?
Ones more reactive than carbon, e.g. aluminium
What are the two main disadvantages of using electrolysis to extract metals?
Requires a large amount of energy to melt the compounds and to produce the necessary electricity
Define oxidation in terms of electrons
Oxidation is the loss of electrons
What is produced at the anode and cathode in the electrolysis of aluminium oxide?
Aluminium at the cathode and oxygen at the anode
Define reduction in terms of electrons
Reduction is the gain of electrons
What is the reactivity series?
A list of elements ordered by their reactivity. (K, Na, Ca, Mg, Al, (C), Zn, Fe, (H), Cu, Ag, Au)
How can metals be placed in order of their reactivity?
Add the metals to water or acid and see which ones react the most (by how much fizzing there is)
What is the name for a reaction where oxygen is removed from a compound?
Reduction
Explain why zinc can be extracted from zinc oxide with carbon but magnesium cannot be extracted from magnesium oxide with carbon
Magnesium is more reactive than carbon (1), Zinc is less reactive than carbon (1), Carbon can therefore remove oxygen from zinc oxide but not magnesium oxide (1)
Explain why gold and silver can be found naturally in the Earth’s crust
It is very unreactive
What process is used to extract metals more reactive than carbon? Why?
Electrolysis. It is a stronger form of reduction.
Define an ore
A material containing enough metal in it for it to be economically worthwhile to extract the metal.
Define a displacement reaction
A reaction in which a more reactive element takes the place of a less reactive element in one of its compounds or in solution
Which of the substances below has been oxidized and which has been reduced? Al³⁺ + Fe → Fe³⁺ + Al
Aluminium has been reduced and iron has been oxidised
Show two half equations for the reaction below: Al³⁺ + Fe → Fe³⁺ + Al
Al³⁺ + 3e⁻ → Al, Fe → Fe³⁺ + 3e-
What is phytoextraction
Growing plants on areas of low grade ore, to concentrate the metal in the plant then extracting the metal from the plant.
What are the advantages of phytoextraction?
Allows us to use low-grade ore, doesn’t produce carbon dioxide and pollute the atmosphere
What are the stages of a life cycle assessment?
Effect on the environment of; obtaining raw materials, manufacturing the product, using the product and disposing of the product.
How is copper extracted from its ore?
Heating with carbon.
In this displacement reaction. What is oxidised and what is reduced? CuSO4 + Mg → MgSO4 + Cu
Copper gains electrons and is reduced. Magnesium loses electrons and is oxidised.
How do you prepare a sample of a soluble salt from a base and an acid?
How do you prepare a sample of a soluble salt from an acid and an alkali?
How do you prepare a sample of an insoluble salt from two solutions
