Starter quiz
- What is the reactivity series of metals?
- a list of metals ranked by their melting points
- a list of metals ranked by their reactivity with water, acids, and oxygen ✓
- a table showing how metals combine to form compounds
- a list of elements ranked by their atomic numbers
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- What does the reactivity series of metals help determine?
- the method of extraction. ✓
- the boiling points of metals.
- the abundance of metals.
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- What is electrolysis used for in chemistry?
- to combine elements into compounds
- to measure the reactivity of elements
- to split compounds into their elements using electricity ✓
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- What is a common feature of ores?
- They all contain carbon.
- They are all shiny.
- They contain metals that can be extracted. ✓
- They are always found in pure form.
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- What is required for industrial processes?
- high temperatures and pressures
- large amounts of raw materials and energy ✓
- pure elements in their natural form
- low costs and simple machinery
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- What type of rock is bauxite?
- sedimentary rock ✓
- igneous rock
- metamorphic rock
- volcanic rock
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Exit quiz
- Why can't aluminium be extracted using carbon?
- Aluminium and carbon form a compound.
- Aluminium is above carbon in the reactivity series. ✓
- Aluminium is less reactive than carbon.
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- What is the role of cryolite in aluminium extraction?
- to extract aluminium directly
- to increase the melting point of aluminium oxide
- to lower the melting point of aluminium oxide ✓
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- What ions are present in molten aluminium oxide (Al₂O₃)?
- Al³⁺ and O²⁻ ✓
- Al⁺ and O⁻
- Al²⁺ and O⁻
- Al⁴⁺ and O²⁻
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- During electrolysis, where do aluminium ions move?
- to the anode
- to the cathode ✓
- to the electrolyte
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- Why does the anode need to be replaced during electrolysis?
- It dissolves in aluminium.
- It reacts with cryolite.
- It reacts with oxygen to form carbon dioxide. ✓
- It stop conducting electricity.
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- Why is aluminium recycling economically beneficial?
- It produces more aluminium.
- It requires more carbon electrodes.
- It uses less energy than extracting new aluminium. ✓
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Worksheet
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Presentation
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Lesson Details
Key learning points
- Aluminium is above carbon in the reactivity series and can therefore not be extracted with carbon.
- Impurities are removed from the bauxite ore at the start.
- Cryolite acts as a solvent and allows the electrolysis to take place at a lower temperature.
- Carbon electrodes need to be continuously replaced as they react with oxygen as it is produced, forming carbon dioxide.
- Electrolysis is an expensive process as it requires large amounts of energy.
Common misconception
Understanding why carbon dioxide is produced at the anode, when there is no carbon in aluminium oxide.
Remind students of previous knowledge about combustion reactions. Help them to apply this knowledge to this new situation in the electrolysis cell.
Keywords
Aluminium oxide - a compound consisting of two aluminum atoms and three oxygen atoms
Bauxite - a sedimentary rock with a high aluminium content
Cryolite - a compound used in the smelting of aluminium to lower the melting point
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