Electrochemistry

What this lesson covers

Electrochemistry is a 7-part O Level Chemistry lesson. Each part makes one point and then hands over to the next, so it can be read in a sitting or picked up again at the part you stopped on. It defines the idea in plain words before using it, works through an example step by step, breaks the topic into its parts and compares them, shows where it is used outside the textbook, names the mistakes that cost marks in an exam, ends with a recap of what to remember.

How it begins

Electrolysis is the decomposition of an ionic compound, molten or in solution, by passing an electric current through it. The compound is the electrolyte. The cathode is negative; the anode is positive. Inert electrodes (carbon, platinum) take no part. Cations (positive) move to the cathode and gain electrons, reduction. Anions (negative) move to the anode and lose electrons, oxidation.

The 7 parts

1. The cell, the electrodes, and the rule at each
2. Aqueous solutions: water joins in
3. Copper electrodes, purification and plating
4. Cells: electricity from chemistry
5. Where marks go
6. What to remember
7. Watch one worked through