Electrolysis
Science Practicals: GCSE, topic 2.1.4
Electrolysis
Electrolysis is the process that splits ionic compounds into their constituent (different) elements (the elements that make them up). Electrolysis happens using a solution that conducts electricity.
Electrolyte
- When ionic compounds are melted or dissolved in water, the ions (charged particles that have gained/lost electrons) are free to move around, and the liquid/solution will conduct electricity.
- Ionic compounds that dissolve in water to make a solution that conducts electricity are called electrolytes.
Electrodes
- When a voltage (direct current) is applied across an electrolyte, the charged ions are attracted to the electrode with the opposite charge to the ion.
- Positively charged ions move to the negative electrode (cathode).
- Negatively charged ions move to the positive electrode (anode).
Elements
- When an ion touches an electrode, electrons can be transferred, producing elements.
- E.g. if copper ions (Cu2+) are in a solution and a voltage is applied, they'll move to the cathode (negative electrode). When they touch the cathode, each Cu2+ ion will gain 2 electrons and form a copper metal.
Test yourself on Electrolysis
If copper ions (Cu2+) are in a solution and a voltage is applied, which electrode will they move towards and what will happen when they touch that electrode?
What happens when ionic compounds are dissolved in water?
What happens when we electrolyse molten copper oxide (CuO)?
Which ions are attracted to which electrode?