Introduction
Electrolysis is the process of using energy supplied by electricity to break ionic compounds back into their component atoms. It is an important process that is used, among other things, for the extraction of reactive metals from their ores, as well as the production of hydrogen and oxygen for use in fuel cells. In this unit you will be studying electrolysis of molten and dissolved ionic compounds. By the end of the unit, you will be able to predict the products of electrolysis of different compounds and explain what is happening in terms of movement of electrons.
Specification links
Set 1 - Section 4.4.3
Set 2 & 3 - Section 5.4.3
Task 1: Know
Task 1a: Use look, cover, write, check and quizlet to learn the answers to the core questions and the keywords for this topic.
Learn
Task 2: Introduction to electrolysis
Task 2b: Make notes that:
Define electrolysis.
Draw and label a setup for carrying out electrolysis
Define the terms electrolyte, cathode, anode
Explain why electrolysis can only be carried out on ionic compounds that are molten or dissolved in water
Task 2c: Write word and symbol equations for the electrolysis of:
Sodium chloride (NaCl)
Magnesium oxide (MgO)
Copper Iodide (CuI2)
Task 2d: Copy and complete the table:
Task 3: Changes at the electrodes
Task 3b: Make notes that:
Describe how metal ions are turned back into atoms.
Define reduction in terms of electrons
Describe how non-metal ions are turned back into atoms
Define oxidation in terms of electrons
Task 3c: Copy and complete this paragraph:
_______________ charged ions are attracted to the cathode.
The ions ________ electrons, turning them back into _______.
The ions are ____________ back into atoms.
Sets 1&2: Task 3d: Copy and complete this table:
Task 4: The extraction of aluminium
Task 4b: Make notes that include:
Describe the properties of aluminium and its uses
Explain why aluminium cannot be extracted from its ore by heating with carbon.
Explain why aluminium oxide is mixed with cryolite
Explain the economic and environmental benefits of using cryolite
Copy / print out the the diagram above
Sets 1 & 2 - Write half equations for the reaction at each electrode
Task 4c: Complete and self mark the exam question for your set
Task 5: Electrolysis of aqueous solutions
Task 5c: Make notes that:
Describe the extra ions that water provides in a solution of an ionic compound
Copy and complete these sentences:
In _________ ionic compounds, the only ions present are those in the compound.
In _________ ionic compounds, ___ and ___ ions are present from the water in addition to the ions from the compound.
In solutions, ____________ charged ions are attracted to the cathode. _______ ions come from the salt and ________ ions come from the water.
The ion from the _______ reactive element _______ electrons and so is _________. The other ion stays in solution.
In electrolysis of solutions, ____________ charged anions are attracted to the anode.
If the anion is a ______ (such as chloride, bromide or iodide), they _______ electrons and are ___________ to form a halogen (chlorine, bromine or iodine).
If the anion is anything else (such as _______ or nitrate), the ___________ ions from the water are ________ to form _______.
Predict the product at the cathode of electrolysis of solutions the following salts. Explain your choices.
Sodium chloride
Silver (I) nitrate
Copper (II) sulfate
Iron (III) iodide
Set 1&2 - Write half equations for each reaction
Predict the product at the anode of electrolysis of solutions the following salts. Explain your choices.
Sodium chloride
Silver (I) nitrate
Copper (II) sulfate
Iron (III) iodide
Set1 & 2 - Write half equations for each reaction
Explain how electrolysis of sodium chloride solution (brine) can result in three different products
Task 6: Electrolysis required practical
Task 6a: Watch the video
Task 6b: Make notes that:
Write a method for the electrolysis of solutions
Predict the products of electrolysis of sodium sulfate and copper chloride
(Set 1&2) Write half equations for each reaction
Task 7: Summary
Task 7a: Watch the video
Task 7b: Read through the BBC Bitesize revision material for this topic and complete the quiz
Complete the Seneca Learning units for this topic
Task 7d: Make a mind map or single page revision summary of this topic. Use the specification links to help you.
Set 1 - Section 4.4.3
Set 2 & 3 - Section 5.4.3